KR20180108421A - Process for preparing granular oxamide - Google Patents

Abstract

The present invention provides a granular oxamide, which has a high hardness of fertilizer particles, high stability in water shape and has stable slow-releasing properties to reduce the number of additional fertilizers and reduce the burden on the additional fertilizer. A mixture containing 0.5 parts by weight or more of polyvinyl alcohol or modified polyvinyl alcohol relative to 100 parts by weight of an oxamide powder is produced by passing through high-speed stirring and assembly in an inclined mixing pan container, followed by drying.

Description

Technical Field [0001] The present invention relates to a process for preparing granular oxamide,

The present invention relates to a process for producing particulate oxamide, and more particularly to a process for producing particulate oxamide having a high inhibitory ineffectiveness with high fertilizer hardness and high collapse resistance in water or soil.

One of the characteristics of the agricultural structural changes from 2010 to 2015 is that the rate of decrease in the number of agricultural business owners and the number of sales farmers is the highest in the past, and aging of agriculture workers is progressing gradually. Therefore, a fertilizer containing a slow-release nitrogen in which the physical burden of the fertilizing work is reduced as much as possible and the number of times of fertilization is minimized is widely used in a farmhouse site. Oxamide [(CONH ₂ ) ₂ ] is one of the representative examples of this, and is an odorless white powder having excellent solubility in water and no weakness against crops.

However, the oximeide of the powder is relatively rapidly mineralized by the microorganisms in the soil (which means that the oxamide is decomposed to the form absorbed by the plant) and the mineralized nitrogen component is ammonium sulphate, urea, ammonium chloride ) And ammonia nitrate (nitrogen nitrate fertilizer), it is not possible to sufficiently exhibit the slow-release characteristics of oxamide. In addition, even when oxamide is kneaded in the chemical fertilizer, the fertilizer particles are rapidly disintegrated under the flooded condition, so that they can be decomposed rapidly by the microorganisms involved in decomposition, and can not exhibit the slow-action ineffectiveness.

In general, it is possible to inhibit the inactivation of oxamide by lowering the rate of mineralization of oxamide by inhibiting the contact of microorganisms decomposing oxamide and oxamide by controlling the elution of oxamide into water or soil. In order to control the dissolution of oxamide into water or soil, it is necessary to make granules which are as high in particle strength as possible and which are hardly collapsed in water or in soil.

Examples of the binder for promoting assembly of the fertilizer include bentonite, molasses, ligninsulfonate, starch, konjac powder, sodium arginate, carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyacrylamide (PAM) Gypsum, and sodium salt of corrosion are known (Non-Patent Document 1).

By using these, the particle strength of the fertilizer particle containing oxamide and the property (in water shape stability) that the particle is maintained without being disintegrated in water, such as stability in water, are controlled to control the contact of the oximeide with the microorganism (Patent Document 1). Oxamoid powder is bonded to a rod-like shape by extrusion molding (Patent Document 1), and oxamide powder is bonded by polyvinyl alcohol to form a rod- After granulating the granulated product after extrusion molding, the granulated product is deformed into a spherical shape by a high-speed motor-driven granulator (Patent Document 2), and an iron compound such as iron sulfate, iron chloride and iron nitrate, and ammonium salt of phosphoric acid such as monoammonium phosphate (Patent Literature 3), and a method of preparing a mixture containing oxamide, gypsum, and sulfuric acid alumina Aluminum compound such as aluminum chloride and aluminum nitrate and an ammonium phosphate salt such as ammonium phosphate is assembled with a bowl type granulator or an extrusion granulator (patent document 4), oxamide, ammonium chloride, ammonium phosphate and gypsum And then assembled into a bowl-type granulator, an extrusion granulator, etc. (Patent Document 5), and as a fertilizer is disclosed.

In Patent Document 6, polyvinyl alcohol having a degree of polymerization of 1800 or less and a degree of saponification of 90 mol% or less and a raw material fertilizer (specifically, a processed molybdophosphate fertilizer, a light silicate fertilizer, a mixed phosphoric acid fertilizer and a harmful fertilizer) Discloses a granular fertilizer which is assembled to provide a granular fertilizer having a high particle strength and an excellent underwater decomposability at low temperatures.

However, in the method of Patent Document 1, since the hardness of the granular oxamide is as low as 2 kgf or less, it is a problem that the powder is formed in the bag after molding. In the method of Patent Document 2, the hardness of the spherical oxamide is as low as 3 kgf or less. Further, in order to obtain spherical shape, the spherical oxamide is mixed with a biaxial rotor type mixer and then subjected to extrusion molding. It is necessary to manufacture by two or more kinds of apparatuses using the same. Further, in the methods of Patent Documents 3, 4 and 5, since the hardness of the granular fertilizer is as high as 5 to 9 kgf, there is a drawback that the amount of the nitrogen derived from the oxamide in the granular fertilizer is reduced because the ratio of the additive to the powdery oxamide is high. The stability of the granular oxamide in the in-water shape stability, which is directly related to the ineffective stability of the granular oxamide, is a result in a short period of time of 2 weeks in Patent Document 1, 1 hour in Patent Documents 3 and 4, and 10 hours in Patent Document 5, Or the ineffectiveness of the slowing effect in the soil is insufficient. Patent Document 6 is a technique for providing a granular fertilizer which is an object of the present invention and is excellent in collapsibility in water different from granular oxamide which is hardly collapsed in water.

Patent Document 7 discloses an example of an assembling method for producing a coating nitrification-inhibiting material compounding fertilizer comprising a coating nitrification-inhibiting material formed by coating a nitrification-inhibiting agent with a coating material, and a fertilizer containing ammonia nitrogen and / or urea nitrogen A method of adding a nitrifying inhibitor and a powder such as fertilizer to an inclined fan type granulator, and a method of assembling an aqueous solution of ligninsulfonic acid salt or molasses pulp as a binder, a method of using an extrusion granulator, a method of using a mixing granulator such as an Irish mixer And the like are described.

Patent Document 8 discloses a granular nitrification inhibitor made by mixing a nitrification inhibitor and a diluent (except for a combination of nitrate nitrogen and ammonia nitrogen as a nitrogen component) As an example of an assembling method, a nitrification inhibitor, a chemical fertilizer or the like powder is added to an inclined fan type granulator, and an aqueous solution of ligninsulfonic acid salt, molasses pulp, or the like is assembled as a binder A method of using an extrusion granulator, a method of using a mixing granulator such as an Irihmic mixer, and the like are described.

However, a graded Irish mixer is not used for the preparation of the granulation of oxamide.

Patent Document 1: JP-A-59-169527 Patent Document 2: JP-A-2-145493 Patent Document 3: Japanese Patent Publication No. 6-2628 Patent Document 4: Japanese Patent Publication No. 6-2629 Patent Document 5: Japanese Patent Publication No. 6-2630 Patent Document 6: Japanese Patent Application Laid-Open No. 2006-21968 Patent Document 7: JP-A No. 2000-53481 (Claim 1, paragraph 0011, Production Examples 1 and 6) Patent Document 8: Japanese Patent Application Laid-Open No. 2000-53482 (Claim 1, paragraph 0014, Production Examples 1 and 2)

Non-Patent Document 1: "fertilizer processing" assembly promoter (binder) BSI Biological Science Institute

The object of the present invention is to provide granular oxamide having a high fertilizer hardness, high collapse resistance in water or soil, and stable slow-release ineffectiveness.

As a result of intensive research to solve the above problems, the present inventors have found that when oxamide contains polyvinyl alcohol or modified polyvinyl alcohol and is stirred and assembled at high speed in an inclined mixing pan, it is dried, And the grain shape stability can be maintained at a high level even under field conditions. Thus, the present invention has been accomplished.

That is, the gist of the present invention is as follows.

(1) A process for producing granular oxamide, which comprises mixing a mixture containing 0.5 parts by weight or more of polyvinyl alcohol or modified polyvinyl alcohol with 100 parts by weight of oxamide powder in an inclined mixing pan, Gt;

(2) a mixer for rotating independently of the mixing pan, which is disposed at an eccentric position from the center position of the mixing pan, and a scraper fixedly disposed inside the mixing pan; The production process according to the above (1), wherein high-speed stirring and assembly are carried out using a stirring mixer.

(3) The production method according to (2) above, wherein the time for high-speed stirring and assembly after addition of polyvinyl alcohol or modified polyvinyl alcohol and water is 13 to 60 minutes.

According to the present invention, granular oxamide having high hardness of fertilizer and high resistance to collapse in water or soil can be provided and stable ineffectiveness and ineffectiveness can be exhibited, thereby reducing the number of times of cultivation during crop cultivation. The burden can be reduced.

1 is a schematic perspective view showing an example of a high-speed stirring mixer used in practicing the present invention.
2 is a graph showing the results of the mineralization test at 25 ° C under paddy conditions.

The polyvinyl alcohol or modified polyvinyl alcohol used in the present invention has a degree of polymerization of 1300 to 2400, a viscosity (mPa · S) of 15 to 50, a degree of saponification (mol%) of 90 or more, preferably a degree of polymerization of 1700 to 1800, It is preferable that the viscosity (mPa · S) is 20 to 30 and the degree of saponification (mol%) is 98.0 to 99.7, but it is not limited to this range.

The modified polyvinyl alcohol is not particularly limited, and for example, an acid-modified polyvinyl alcohol (hereinafter also referred to as "acid-modified PVA"), ethylene-modified polyvinyl alcohol and the like can be used.

The acid-modified PVA is a vinyl alcohol polymer containing a predetermined amount of a carboxyl group or a sulfonic acid group. The former is referred to as a carboxylic acid modified PVA, and the latter as a sulfonated modified PVA.

The carboxylic acid modified PVA can be produced by introducing a compound having a carboxyl group into polyvinyl alcohol by a conventionally known method. Examples of the compound containing a carboxyl group include fumaric acid, maleic acid, itaconic acid, maleic anhydride, phthalic anhydride, trimellitic anhydride, acrylic acid and salts thereof.

The sulfonic acid-modified PVA can be produced by introducing a compound having a sulfonic acid group into polyvinyl alcohol by a conventionally known method. Examples of the compound having a sulfonic acid group include ethylene sulfonic acid, allylsulfonic acid, methallylsulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, and salts thereof.

Ethylene-modified polyvinyl alcohol is obtained by saponifying a copolymer of vinyl ester and ethylene. Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl sebacate and the like.

The content of the polyvinyl alcohol or the modified polyvinyl alcohol in the particulate oxamide of the present invention is 0.5 part by weight or more, preferably 1 to 10 parts by weight, relative to 100 parts by weight of the oxamide powder from the viewpoint of ensuring the particle hardness and stability in the water. , And more preferably 1 to 2 parts by weight. If the content of the polyvinyl alcohol or the modified polyvinyl alcohol is less than 0.5 parts by weight, the effect as a binder at the time of granulation is weak and the effect of increasing the particle hardness after granulation is lowered. On the other hand, if the content exceeds 10 parts by weight, the nitrogen component of granular oxamide is lowered, The quality drops.

Next, preferred embodiments of the process for producing particulate oxamide of the present invention will be described.

Initially, polyvinyl alcohol or modified polyvinyl alcohol is dissolved in the following manner. The polyvinyl alcohol or the modified polyvinyl alcohol metered while stirring the room temperature water is gradually added, and heating is continued while stirring is continued. After the liquid temperature reaches 90 to 95 ° C, stirring is continued for 1 to 2 hours while maintaining the temperature. Thereafter, the heat source is cut to weaken the agitating force and gradually cooled to prepare an aqueous solution of polyvinyl alcohol or denatured polyvinyl alcohol in a predetermined concentration. The concentration of the polyvinyl alcohol or the modified polyvinyl alcohol solution is not particularly limited, but 10 to 15% of the solution is suitable as viscosity in handling or as an addition amount in producing fertilizer. Next, the solution prepared by dissolving or dispersing polyvinyl alcohol or modified polyvinyl alcohol so as to have a weight ratio of 0.5 part by weight or more based on 100 parts by weight of the oxamide powder put into the pelletizer was gradually added, and the pellet was stirred and assembled at a high speed in an inclined- Lt; / RTI > The polyvinyl alcohol or the modified polyvinyl alcohol to be added to the oxamide powder is preferably added in the form of a liquid in order to uniformize the binding force between the raw material powders. In addition to the oxamide powder, a mineral powder or the like may be added in order to adjust the volume specific gravity or to prevent floating in water.

The granulator used for the assembly is a high-speed agitation granulator (hereinafter referred to as an inclined-type Irihmic mixer) having an inclined-type mixing pan container of Nippon-Irihicho Co., Ltd. Details are disclosed in Japanese Patent No. 4406328, Assembly by high-performance mixer featuring production "Fundamentals and Application of Powder Technology" Chemical Device Separated in the September issue, Industrial Communication Agency, 2005.

1 is a schematic perspective view showing an example of a high-speed stirring mixer used in practicing the present invention.

As shown in FIG. 1, the high-speed stirring mixer 1 used in the present invention comprises a mixing pan 2 for containing a to-be-stirred object and rotating in a state containing a to-be-stirred object, (Also referred to as a " stirrer ") 3 disposed at an eccentric position from the center position of the mixing pan 2 and rotating independently of the mixing pan 2, And a scraper 4 fixedly disposed. The mixing fan 2 and the mixing tool 3 can independently set the rotating direction and the number of revolutions and the case where the rotating direction of the mixing pan 2 and the mixing tool 3 are opposite to each other, It is possible to stir by two kinds of stirring methods when the rotating direction of the fan 2 and the mixing tool 3 are the same direction.

The outline of the operation procedure is as follows. After the feedstock is fed into the apparatus, the peripheral speed of the rotor is raised (usually 1 to 10 m / s, preferably 2 to 6 m / s) to homogenize the raw material. Next, polyvinyl alcohol or modified polyvinyl alcohol liquid and addition water are added. The rotor is rotated at a peripheral speed (usually 10 to 40 m / s, preferably 15 to 35 m / s) to perform dispersion and assembly. The time for high-speed agitation and agglomeration after addition of polyvinyl alcohol or modified polyvinyl alcohol and water is preferably 13 minutes or more in terms of the target particle diameter generation rate, and 60 minutes from the viewpoint of preventing a large agglomerate state from being caused by adhesion of particles Or less. The time for the high-speed stirring and assembly is more preferably 15 to 45 minutes, and still more preferably 20 to 45 minutes. Thereafter, the peripheral speed of the rotor is lowered (1 to 10 m / s, preferably 2 to 6 m / s), and finally the mixture is discharged from the mixer. The obtained granular material is heated and dried in a drier to prepare granular oxamide. The drying temperature is usually 65 to 130 ° C, preferably 90 to 120 ° C.

The shape and size of the particulate oxamide of the present invention is not particularly limited, but is usually a granular particle having a particle size within a range of 1 to 10 mm. Particularly, when the particle diameter is within the range of 2 to 4 mm, scattering during fertilization can be reduced and workability is favorable. In addition, even when the granular composition according to the present invention is mixed with other harmful fertilizers, the classification is less likely to be good.

Example

Hereinafter, the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited to these examples.

The polyvinyl alcohol (PVA) or modified polyvinyl alcohol (modified PVA) was used in an amount of 94.00% or higher in pure water. The addition amount (%) is expressed by the weight ratio with respect to the oxamide powder.

(Example 1) Production of particulate oxamide containing 1% modified PVA by an inclined Irihmic mixer

And 2.7 parts by weight of water were immersed in a hot water bath at room temperature, and a stirring motor was set. While water was stirred, 0.3 part by weight of modified polyvinyl alcohol (product of Kuraray Co., Ltd., degree of polymerization 1300, degree of saponification 92 to 98) . The mixture was heated with stirring, reached 95 DEG C, and stirred for 2 hours while maintaining the temperature. The denatured PVA was confirmed to be completely dissolved, and the stirring force was weakened and gradually cooled to prepare a 10% solution.

20 parts by weight of oxamide powder was put into a mixing pan vessel of a gradient type Irihmic mixer (Intensive Mixer R02, manufactured by Nippon-Iryhi Co., Ltd., the same applies hereinafter), and 2 parts by weight of a modified 10% And mixed at a peripheral speed of 6 m / s (900 rpm) for 1 minute and 15 seconds. Next, 3.53 parts by weight of water was added and dispersed and assembled at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 23 minutes. The peripheral speed of the rotor was lowered to 900 rpm for 1 minute and 30 seconds and then discharged. The discharged product was dried in a dryer at 105 ° C for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 1% of modified PVA.

(Example 2) Preparation of granular oxamide having PVA content of 2% by an inclined Irihmic mixer

And 5.4 parts by weight of water was immersed in a hot water bath at room temperature, and a stirring motor was set. While stirring the water, 0.6 part by weight of PVA was gradually added. The mixture was heated with stirring, reached 95 DEG C, and stirred for 2 hours while maintaining the temperature. It was confirmed that the PVA was completely dissolved, and the solution was gradually cooled to weaken the stirring force to prepare a 10% solution.

20 parts by weight of oxamide powder was put into a mixing pan of a gradient type Irihmic mixer, and 4 parts by weight of the prepared 10% PVA solution was added and mixed at a peripheral speed of the rotor of 6 m / s (900 rpm) for 1 minute. Further, 1.66 parts by weight of water was added thereto, followed by dispersion and assembly at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 21 minutes. The peripheral speed of the rotor was lowered to 900 rpm for 2 minutes and discharged. The discharged product was dried for 4 hours in a dryer at 105 ° C, and granulated to a particle size of 2 to 4 mm to obtain granular oxamide containing 2% of PVA.

(Example 3) Preparation of granular oxamide having PVA content of 1% by an inclined Irihmic mixer

20 parts by weight of oxamide powder was put into a mixing pan of a gradient type Irihmic mixer, 2 parts by weight of a 10% PVA solution prepared in Example 2 was added, and the mixture was mixed at a peripheral speed of 6 m / s (900 rpm) for 1 minute. Further, 3.63 parts by weight of water was further added thereto, followed by dispersion and assembly at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 22 minutes. The peripheral speed of the rotor was lowered to 6 m / s (900 rpm) for 2 minutes and discharged. The discharged product was dried in a dryer at 105 캜 for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 1% PVA.

(Example 4) Preparation of granulated oxamide containing 4% of modified PVA by an inclined Irihmic mixer

And 4.8 parts by weight of water was immersed in a hot water bath at room temperature, and a stirring motor was set. While water was stirred, 1.2 parts by weight of modified polyvinyl alcohol was gradually added. The mixture was heated with stirring, reached 95 DEG C, and stirred for 2 hours while maintaining the temperature. After confirming that the modified PVA was completely dissolved, the stirring force was weakened and gradually cooled to prepare a 20% solution.

20 parts by weight of oxamide powder was put into a mixing pan of a gradient type Irihmic mixer, and 4 parts by weight of a 20% solution of the modified PVA prepared was added and mixed at a peripheral speed of the rotor of 6 m / s (900 rpm) for 1 minute. Further, 2.3 parts by weight of water was further added and dispersed and assembled at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 18 minutes. The peripheral speed of the rotor was lowered to 6 rpm (900 rpm) for 2 minutes and discharged. The discharged product was dried in a dryer at 105 캜 for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 4% of modified PVA.

(Example 5) Production of particulate oxamide containing 0.5% of modified PVA by an inclined Irihmic mixer

20 parts by weight of oxamide powder was put into a mixing pan of a gradient type Irihmic mixer, 1 part by weight of a 10% solution of modified PVA prepared in Example 1 was added and mixed at a peripheral speed of 6 m / s (900 rpm) of the rotor for 1 minute and 15 seconds Respectively. Next, 4.4 parts by weight of water was added, and dispersion and assembly were carried out for 23 minutes at a peripheral speed of 19 m / s (3000 rpm) of the rotor. The peripheral speed of the rotor was lowered to 900 rpm for 1 minute and 30 seconds and discharged. The discharged product was dried in a dryer at 105 ° C for 4 hours and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 0.5% of modified PVA.

(Example 6) Production of particulate oxamide containing 0.5% of PVA by an inclined Irihmic mixer

20 parts by weight of oxamide powder was put into a mixing pan of a gradient type Irihmic mixer, 1 part by weight of a 10% PVA solution prepared in Example 2 was added and mixed at a peripheral speed of 6 m / s (900 rpm) of the rotor for 1 minute and 15 seconds . Next, 4.4 parts by weight of water was added, and dispersion and assembly were carried out for 23 minutes at a peripheral speed of 19 m / s (3000 rpm) of the rotor. The peripheral speed of the rotor was lowered to 900 rpm for 1 minute and 30 seconds and discharged. The discharged product was dried in a dryer at 105 ° C for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 0.5% of PVA.

(Comparative Example 1) Production of granulated oxamide containing 1% modified PVA by a horizontal Irihmic mixer

20 parts by weight of oxamide powder was put into a mixing pan vessel of a horizontal type IRHYMIXER (Nippon IRICHI Co., Intensive Mixer DE14 type), 2 parts by weight of a 10% solution of modified PVA prepared in Example 1 was added, At a peripheral speed of 13 m / s (600 rpm) for 1 minute. Further, 3.65 parts by weight of water was added and dispersed and assembled at a peripheral speed of 31 m / s (1500 rpm) of the rotor for 25 minutes. The peripheral speed of the rotor was reduced to 13 m / s (600 rpm) for 2 minutes and discharged. The discharged product was dried in a dryer at 105 ° C for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 1% of modified PVA.

(Comparative Example 2) Preparation of particulate oxamide having a modified PVA 1% by means of a bowl type granulator

20 parts by weight of oxamide powder was put into a pan container of a mortar granulator (motor-driven self-assembly fan granulator manufactured by Sumitomo Heavy Industries, Ltd.), 2 parts by weight of a 10% solution of modified PVA prepared in Example 1 was added, And mixed at a peripheral speed of 1.6 m / s (40 rpm) for 15 minutes. Further, 8.02 parts by weight of water was gradually added and the mixture was assembled at a peripheral speed of 1.6 m / s (40 rpm) of the fan for 30 minutes. The assembled mouthpiece was dried in a dryer at 105 ° C for 4 hours and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 1% of denatured PVA.

(Comparative Example 3) Production of particulate oxamide containing 1% modified PVA by an extrusion granulator

20 parts by weight of powder oxamide was added to a biaxial rotor type mixer (Fuji Powder Co., Ltd.), 2 parts by weight of a 10% solution of modified PVA prepared in Example 1 and 6.46 parts by weight of water were added and sufficiently kneaded.

The kneaded product was extruded and assembled by putting it in a screw extruding granulator (product of Fuji Powder Co., screen mesh 1.2 mm). The granules extruded from the screen were dried in a dryer at 105 DEG C for 24 hours and then cut to a length of 0.5 to 1 cm to obtain granular oxamide containing 1% of pelletized modified PVA.

(Comparative Example 4) Production of granular oxamide (no addition of an assembly promoter) by an inclined Irihmic mixer

20 parts by weight of oxamide powder was put into a mixing pan of an inclined Irihmic mixer, 3.81 parts by weight of water was added, and the mixture was mixed at a rotor speed of 6 m / s (900 rpm) for 1 minute. Further, 1.82 parts by weight of water was further added thereto, followed by dispersion and assembly at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 32 minutes. The peripheral speed of the rotor was reduced to 900 rpm at a speed of 6 m / s for 2 minutes and discharged. The discharged product was dried in a dryer at 105 DEG C for 4 hours and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide.

(Comparative Example 5) Preparation of particulate oxamide containing 2% of starch by an inclined Irish mixer

20 parts by weight of oxamide powder and 0.4 part by weight of starch were put into a mixing pan of a gradient type Irrigation mixer and mixed at a rotor speed of 6 m / s (900 rpm) for 1 minute. Next, 5.1 parts by weight of water was added and mixed at a peripheral speed of 6 m / s (900 rpm) of the rotor for 1 minute. Further, dispersion and assembly were carried out at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 25 minutes, and the peripheral speed of the rotor was lowered to 6 m / s (900 rpm) for 2 minutes and discharged. The discharged product was dried in a dryer at 105 ° C for 4 hours, and granulated to a particle size of 2 to 4 mm to obtain granular oxamide having 2% of starch.

(Comparative Example 6) Preparation of particulate oxamide containing 2% of carboxymethyl cellulose (CMC) by an inclined type Irrigation mixer

20 parts by weight of oxamide powder and 0.4 part by weight of CMC were put into a mixing pan of a gradient type Irrigation mixer and mixed at a peripheral speed of the rotor of 6 m / s (900 rpm) for 1 minute. Next, 5.1 parts by weight of water was added and mixed at a peripheral speed of 6 m / s (900 rpm) of the rotor for 1 minute. Further, dispersion and assembly were carried out at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 23 minutes, and the peripheral speed of the rotor was lowered to 6 m / s (900 rpm) for 2 minutes and discharged. The discharged product was dried in a dryer at 105 캜 for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 2% of CMC.

(Comparative Example 7) Preparation of granular oxamide containing minerals, iron sulfate and phosphoric acid by an inclined Irihmic mixer

20 parts by weight of oxamide powder, 1.25 parts by weight of mineral (basalt powder), 0.42 part by weight of iron sulfate, and 2.5 parts by weight of phosphoric acid were put into a mixing fan vessel of an inclined type Irihmic mixer and the mixture was stirred at a rotor speed of 6 m / And mixed for 1 minute. Next, 3.11 parts by weight of water was added and mixed at a peripheral speed of 6 m / s (900 rpm) of the rotor for 1 minute. Further, dispersion and assembly were performed at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 15.5 minutes, and the peripheral speed of the rotor was lowered to 900 rpm for 2.75 minutes and discharged. The discharged product was dried in a dryer at 105 캜 for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing iron sulfate and phosphoric acid.

(Comparative Example 8) Preparation of particulate oxamide containing 0.2% modified PVA by a slant type Irish mixer

20 parts by weight of oxamide powder was put into a mixing pan of a gradient type Irihmic mixer, 0.4 parts by weight of a 10% solution of modified PVA prepared in Example 1 was added, mixed at a rotor speed of 6 m / s (900 rpm) for 1 minute and 15 seconds Respectively. Next, 4.88 parts by weight of water was added, and dispersion and assembly were carried out for 23 minutes at a peripheral speed of 19 m / s (3000 rpm) of the rotor. The peripheral speed of the rotor was lowered to 900 rpm for 1 minute and 30 seconds and then discharged. The discharged product was dried in a dryer at 105 ° C for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 0.2% of modified PVA.

(Comparative Example 9) Preparation of particulate oxamide containing 0.2% of PVA by an inclined Irihmic mixer

20 parts by weight of oxamide powder was put into a mixing pan of a gradient type Irihmic mixer, 0.4 parts by weight of a 10% PVA solution prepared in Example 2 was added, and the mixture was mixed at a peripheral speed of 6 m / s (900 rpm) for 1 minute and 15 seconds . Next, 4.88 parts by weight of water was added, and dispersion and assembly were carried out for 23 minutes at a peripheral speed of 19 m / s (3000 rpm) of the rotor. The peripheral speed of the rotor was lowered to 900 rpm for 1 minute and 30 seconds and then discharged. The discharged product was dried in a dryer at 105 캜 for 4 hours, and then sieved to a particle size of 2 to 4 mm to obtain granular oxamide containing 0.2% PVA.

(Evaluation test 1)

Each of the granular oxides obtained in Examples 1 to 6 and Comparative Examples 1 to 9 was examined for hardness and shape stability in water as an evaluation of slow-acting nitrogen fertilizer. These test methods are as follows. In the tests described below, those having particle diameters in the range of 2.85 to 3.50 mm among the obtained granular fertilizers were selected and used.

Moisture: The granular oxamide obtained was pulverized with a pulverizer, and about 5 g of a powder having passed through a 0.5 mm sieve was precisely weighed and dried in a dryer at 105 ° C for 3 hours. The reduced weight was divided by the weight of the sample and multiplied by 100. The results are shown in Tables 1, 2, and 3.

Hardness: The particle hardness of the granular oxamide of 20 particles was measured using a keyed night hardness tester, and the results are shown in Tables 1, 2 and 3.

Underwater shape stability: 20 particles of granular oxamide were added to a Mary clone bottle containing 50 ml of water, and then the collapsed state of the particle surface was maintained at 25 ° C for 3 days, 14 days , 28 days, and 56 days after the administration. 3: Disintegration of particle surface 31 to 50%; 4: Collapse of particle surface 51 to 70%; 3: Disintegration of surface of particle 3: Disintegration state 0: No collapse 1: Collapse of particle surface 10% or less 2: Collapse of particle surface 11 to 30% , 5: 71 to 90% of collapse of particle surface, and 6: Collapse of particle surface of 91 to 100% are shown in Tables 1, 2 and 3.

As shown in Table 1, in the method using the granulation apparatuses of Comparative Examples 1 to 3, the hardness of the granular oxamide was increased to 6.3 kgf in Example 1 while the hardness of the fertilizer particles was 3.1 kgf or less, .

Further, regarding the underwater shape stability, in Comparative Examples 1 to 3, the surface of the particles started to collapse immediately after the water injection, and after 56 days, more than 31% of the surface of the particles collapsed, whereas in Example 1, no collapse was observed even after 56 days.

Table 2 shows the results of comparing the assembly promoter using an inclined Irihmic mixer.

The hardness of the fertilizer granules of Comparative Example 4 to which no granulation accelerator was added was 3 kgf or less. And 5.3 and 4.5 kgf in Comparative Examples 5 and 6, respectively. In Comparative Example 7, there was no significant difference from Example 2 at 6.6 kgf.

In Comparative Example 4, however, no collapse of the particle surface was observed immediately after water injection, but collapse progressed after 3 days and more than 51% of the particle surface collapsed after 56 days. In Comparative Examples 5, 6 and 7, even though the hardness was higher than Comparative Example 4, the surface of the particles began to collapse immediately after the water injection, and after 56 days, more than 51% of the particle surface collapsed. In contrast, Example 2 showed no collapse after 56 days.

As shown in Table 3, in Comparative Examples 8 and 9 in which the added amount of PVA or modified PVA was 0.2%, the hardness of the fertilizer particles was 2.8 kgf, and the stability in water also collapsed immediately after the water injection. On the other hand, Examples 1 to 6 in which the addition amount of PVA or modified PVA was 0.5% or more had a hardness of 4.5 kgf or more and a high stability in water.

As described above, granular oxamide having a high hardness, in particular, hardly collapsed in water and high in shape stability, can be produced by the method of the present invention.

(Evaluation test 2: mineralization test at 25 占 폚 under paddy conditions)

(1) Purpose

(Comparative Example 7) comprising a granular oxamide having a modified PVA content of 1% (Example 1) and an inclined Irihmic mixer, a ferrous sulfate and a phosphoric acid-containing granular oxamide prepared by using an inclined Irihmic mixer (Comparative Example 7) .

(2) Test method

Fertilizer particles containing oxazide (with 4 particles corresponding to 24 mg as nitrogen) were mixed in 60 g of dry soil [Tsukuba soil (sand loam)] and placed in a 200 ml beaker. For phosphoric acid and potassium, 12 mg per 60 g of dry soil as a component was added as monopotassium phosphate and potassium chloride. Next, deionized water was added to 140% of the maximum water content of the disclosed soil, covered with a polyethylene film, and then allowed to stand at a constant temperature of 25 ° C for a predetermined period of time.

After a predetermined period of time, the sample in the beaker was subjected to shaking filtration with 300 ml of a 10% aqueous potassium chloride solution, and inorganic nitrogen (amount of NH ₄ and NO ₃ ) was quantitatively determined by the Conway method to calculate an inorganic ratio.

(3) Results

The results are shown in Table 4 and FIG.

As can be seen in Table 4 and FIG. 2, the granular oxamide containing 1% of modified PVA produced by the inclined type Irihmic mixer is superior to the granular oximide prepared by the inclined Irihmic mixer, the iron sulfate and the phosphoric acid-containing granular oxamide The mineralization was slow and the efficacy was slow and ineffective.

That is, the granular oxamide containing 1% of the modified PVA as the present invention has a higher hardness than the granular oxamide having the iron sulfate and phosphoric acid produced by the slant type IRHYMIXER but has a high stability in the water and exhibits a slow and ineffective effect It became clear.

(Example 7) Comparison of assembly time

20 parts by weight of oxamide powder was put into a mixing pan vessel of an inclined type Irihmic mixer (Intensive Mixer R02, manufactured by Nippon-Irieich Co., Ltd.), 2 parts by weight of a 10% solution of modified PVA prepared in Example 1 was added, At a peripheral speed of 6 m / s (900 rpm) for 1 minute. Next, 3.20 parts by weight of water was added and dispersed and assembled at a peripheral speed of the rotor of 19 m / s (3000 rpm) for 5 minutes, 10 minutes, or 15 minutes, and the peripheral speed of the rotor was reduced to 900 rpm at 6 m / s for 30 seconds . The discharged product was dried in a dryer at 105 캜 for 4 hours, and the particle size distribution was measured.

Table 5 shows the results of the particle size distribution (1 mm sieve and 1 mm, 2 mm, 4 mm sieve weight divided by total weight, expressed as a percentage).

As shown in Table 5, granular oxamide of 2 mm to 4 mm was less when the modified PVA and water were added for 5 minutes and 10 minutes, whereas when granulated for 15 minutes, the granular oxamide of 2 mm to 4 mm was reduced to 50% Or more.

1 high-speed stirring mixer
2 mixing pan
3 mixing tool
4 Scraper

Claims (3)

Wherein the mixture containing 0.5 parts by weight or more of polyvinyl alcohol or modified polyvinyl alcohol with respect to 100 parts by weight of oxamide powder is agitated at high speed in a mixing pan and then dried. The method according to claim 1,
A high speed stirring mixer provided with a rotating mixing fan and a mixing tool disposed at an eccentric position from the center position of the mixing pan and rotating independently of the mixing fan and a scraper fixedly disposed inside the mixing fan, And stirring the mixture at high speed. The method of claim 2,
Wherein the time for high-speed stirring and assembly after adding polyvinyl alcohol or modified polyvinyl alcohol and water is 13 to 60 minutes.

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