JPH11319693A - Coating method for core material particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the coating/granulating method capable of uniformly coating a coating film on a surface of the particles and also capable of treating industrially on a large scale in a short time. SOLUTION: In the coating/granulating method in which the coating resin is applied on the surface of core material particles by supplying heating gas while spraying coating liq. in which the coating resin is dissolved in a solvent on the core material particles and drying the solvent of the coating liq., the temp. of the heating gas to be supplied is kept at the temp. 10-100 deg.C higher than a melting point of the coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating or granulating particles, and more particularly, to a method for forming core particles suitable for granulating or coating agricultural chemicals or fertilizers. It relates to a coating method.

[0002]

2. Description of the Related Art Conventionally, as a device for granulating particles or coating core material particles with a coating film, a mixing and stirring device using a stirring blade such as a Henschel mixer or a Nauta mixer, a rotary drum type coater, a rotary pan type coater. , A device for mixing and stirring by rotating the device itself such as a rotary drop type coater,
There are a vibrating fluidizing device that mixes and agitates by applying vibration, a coating device using a Wurster type or a jet method that blows and mixes particles, and a fluidized bed type coater that floats and flows the particles. Conventionally, granulation and coating of core material particles have been performed by appropriately selecting these devices according to the purpose.

A method of coating particles using a jet method is described in, for example, Japanese Patent Publication No. 38-13896.
The lower part of the cylindrical tank is formed in an inverted conical shape, and the lower end is cut horizontally to form a throttle for gas jet, and a high-speed gas flow is jetted vertically upward into the tank through the throttle. In this method, particles to be coated in a tank are blown up, and simultaneously a coating liquid is sprayed to coat the particles with a coating. Japanese Patent Publication No. 38-2
No. 294 discloses a method in which particles are blown up through a guide tube provided in a central jet portion in a jet tower, and a coating liquid is sprayed from a spray nozzle provided in the tube. In Japanese Patent Publication No. 50-1355, a guide tube is provided in the jet part, and gas is also passed around the jet part to place the particles in a flowing state or in a weightless state close to it, causing troubles such as adhesion of particles. Have been around.

[0004] All of these coating methods using the jet flow method are intended for coating pharmaceuticals, and are preferable methods for small-scale and gentle coating. However, when it is necessary to coat a large amount at low cost, for example, when a fertilizer or the like is to be coated, this method is not an appropriate method. In the case of coating a large amount of particles, it is necessary to use a jet tower having a large diameter. However, when the diameter of the jet tower is large, the whole particles are in a flowing state, and there is a problem that a spouted bed cannot be formed.

To solve this problem, Japanese Patent Publication No. 2-3939
Discloses a technique in which a jet state can be obtained even when a jet tank becomes large. In other words, in order to produce and supply a large amount like fertilizer, a coating device in which a guide tube is provided vertically above an orifice in a jet device using a large-diameter jet tower is used. When introducing the active gas, the flow velocity of the gas at the orifice is set to 20 m / sec or more.
70 m / sec, and the flow velocity in the guide tube is 20 m / sec.
The coating is performed by adjusting the value to c or less.

On the other hand, recently, JP-A-6-9303, JP-A-6-9304, JP-A-6-72805, JP-A-6-80514, JP-A-5-29634 and JP-A-5-29634 have recently been proposed.
As disclosed in JP-A-202078, JP-A-4-202079 and JP-A-6-87684, the active ingredient is not eluted for a certain period after fertilization or the period in which the elution is extremely suppressed (this period is referred to as There is disclosed a coated particle fertilizer in which a film having a so-called timed elution type pattern having an initial elution period) is coated on the surface of the fertilizer particles.

[0007] The coated particle fertilizer in which the surface of the fertilizer particles is coated with a coating having such a time-eluting type elution pattern is inexpensively prepared by using a jet tower as described in JP-B-2-31939. In the case of mass production, the method of attaching the coating resin solution to the particles, and the scattering of the solvent from the attached resin solution, the state of drying greatly affect the production efficiency and the elution pattern of the active ingredient of the obtained coated particle fertilizer. It is thought to have an effect.

When a large amount of coated particle fertilizer is produced using a large spout tower, it is considered important to shorten the drying time in order to increase production efficiency economically. In order to shorten the drying time, it has been often attempted to increase the supply amount of the resin solution and to scatter and dry the solvent contained in the resin solution attached to the particle surface by using a large amount and high-temperature jet gas.

However, when using a jet tower to coat particles having a relatively low melting point such as urea particles, it is generally considered that the temperature of the jet gas must be kept below the melting point of the urea particles. Therefore, no attempt has been made to increase production efficiency by using a hot jet gas. That is,
When coating is performed with the temperature of the jet gas equal to or higher than the melting point of the urea particles, nonuniform solvent scattering and drying occur in the jet tower, and therefore, an annular urea particle deposition layer composed of urea particles existing outside the guide tube. Part of the (fixed bed) is melted and condensed, and urea particles are melted and condensed to the gas jet throttle at the inverted conical tip at the bottom of the tower, which prevents uniform circulation of the particles. It has been thought that practical operations will not be possible.

When the temperature of the jet gas is kept below the melting point of the urea particles to increase the amount of the jet gas, the amount of particles sent from the lower part of the jet tower to the guide tube fluctuates, causing a so-called pulsation phenomenon. Operation becomes unstable. In this case, the coating film of the urea particles is easily damaged, and the obtained coated fertilizer has a large amount of the active ingredient eluted within the initial elution suppression period. That is, many of the obtained coated fertilizers rapidly elute the active ingredient immediately after fertilization. Therefore, it is extremely difficult to produce a large amount of time-dissolved coated fertilizer having a desired dissolution function by a conventional jet method with high production efficiency.

[0011]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present inventors have sought to find out where the cause is. As a result, in the jet method, even if the surface of the urea particles is coated with a coating gas using a high-temperature jet gas at or above the melting point of the urea particles, which was conventionally considered impossible due to fusion of the urea particles and the coating resin. It has been found that the urea particles are kept below the melting point due to the heat of vaporization of the solvent, and that the urea particles do not melt or solidify due to the high-temperature jet gas.

[0012] Further, the present inventors have found that this discovery is not limited to the jet method, but can be applied to conventional coating apparatuses and coating methods, and further to conventional granulating apparatuses and granulating methods, and have completed the present invention. It is a thing.

Accordingly, an object of the present invention is to provide a particle coating method capable of uniformly coating a film on the particle surface, preventing the particles from fusing with each other, and industrially mass-treating the particles. To provide. Since this coating method can be used as it is as a granulation method, the coating method of the present invention includes a granulation method.

[0014]

Means for Solving the Problems In order to achieve the above object, the present invention provides [1] supplying a heating gas while spraying a coating solution obtained by dissolving a coating resin in a solvent onto core material particles to form a coating solution of the coating solution. In the method of coating core particles, in which the surface of the core particles is coated with the coating resin by drying the solvent, the temperature of the supplied heated gas is set to be 10 to 10 lower than the melting point of the coating resin.
The present invention proposes a method of coating core material particles characterized by maintaining the temperature at 0 ° C. higher. [2] In [1], a core material which supplies a heating gas while spraying a coating liquid onto the core material particles. Keeping the temperature of the particles at a temperature lower by 10 to 50 ° C. than the melting point of the coating resin, [3] [1] or [2], in which the core material particles are jetted by supplying a heated gas, [4] In [1] to [3], the coating resin is a polyolefin resin, [5] [1] to
In (4), the solvent is perchlorethylene, trichloroethylene, octane, or toluene;
[6] In the items [1] to [5], the core material particles include fertilizer particles or pesticide particles.

The present invention also provides a coated fertilizer or a coated pesticide having a time-dissolving elution function, which is obtained by the method for coating core particles according to [7] or [6].

Further, the present invention provides a method for cultivating a crop, comprising using the coated fertilizer or the coated pesticide according to [8] or [7].

Hereinafter, the present invention will be described in detail with reference to the drawings.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for coating core particles of the present invention, the core particles to be coated are not particularly limited, and any core particles can be coated. However, the coating according to the method of the present invention is particularly useful for particles that need to control the rate of elution of the active ingredient contained in the particles. The active ingredient varies depending on the purpose of use, use, etc., but urea, ammonium sulfate, ammonium salt, ammonium nitrate, potassium chloride, sulfate potassium, nitrate potassium, sodium nitrate, ammonium phosphate, phosphate potassium, lime phosphate, chelate iron, iron oxide, chloride Fertilizers and insecticides such as iron, boric acid, borax, manganese sulfate, manganese chloride, zinc sulfate, copper sulfate, sodium molybdate, ammonium molybdate, OMUP (clotylidene diurea), IBDU (isobutylidene diurea) and oxamide. , Fungicides, pesticides such as herbicides, and the like. The particles may be granules of one or more active ingredients, or may be granules comprising one or more active ingredients and an inert carrier such as bentonite, zeolite, talc, clay, and diatomaceous earth. good. Further, the above-mentioned active ingredient particles may be coated with a resin or an inorganic substance.

The size of these particles is not particularly limited,
It is preferably from 0.1 to 10 mm, particularly preferably from 1 to 5 mm.

In the coating method of the present invention, the coating resin used for coating the particles is not particularly limited. Especially,
In the case of producing the time-eluting type coated particles, a material and a composition which can strictly control the elution of the active ingredient contained in the particles may be selected. Examples of such a coating resin include a thermosetting resin such as an alkyd resin, a phenol resin, and an epoxy resin; a polyolefin such as polyethylene and polypropylene; and a thermoplastic resin such as polyvinylidene chloride.

Of these, strict like fertilizers and pesticides,
When coating particles containing an active ingredient that requires long-term elution control, it is preferable to use a thermosetting resin or a thermoplastic resin as the coating resin. It is particularly preferable to use a resin.

Preferred thermoplastic resins include polyolefins and copolymers thereof, and polyvinylidene chloride and copolymers thereof. Preferred polyolefins and copolymers thereof are polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / propylene.
Vinyl acetate copolymer, ethylene / carbon monoxide copolymer,
Ethylene / vinyl acetate / carbon monoxide copolymer, ethylene / acrylate copolymer, ethylene / methacrylic acid copolymer, rubber resin, polystyrene, polymethyl methacrylate, etc. Examples of the copolymer include polyvinylidene chloride, vinylidene chloride / vinyl chloride copolymer, and the like. Further, biodegradable polyesters represented by poly-2-hydroxy-2-alkylacetic acid, poly-3-hydroxy-3-alkylpropionic acid and the like can also be mentioned.

The coating resin is dissolved in an organic solvent to prepare a coating solution, and the coating solution is sprayed onto the core particles to perform coating. As organic solvents, perchlorethylene,
Examples thereof include halogen-containing solvents such as trichloroethylene, paraffin solvents such as hexane and octane, and aromatic solvents such as toluene. In particular, perchlorethylene, trichloroethylene, hexane, octane, and toluene are easy to adjust the coating solution concentration because of high solubility of the polyolefin resin, and the boiling points of these organic solvents are close to the melting point of the coating resin, and the heat of vaporization is also high. The drying efficiency is high due to the small size. For this reason, these organic solvents are particularly preferred.

The method of the present invention is particularly effective in a film forming method in which a poor solvent solution of the above-mentioned coating resin is used, sprayed on the particles and flash dried to form a film. In the case of instantaneous drying using a poor solvent for the above resin, a combination of a resin and an organic solvent having a property of dissolving at a high concentration when heated, and precipitating and forming a jelly-like resin when cooled is preferable. Since the film formed by this combination forms a very dense film, it is particularly suitable for forming a time-eluting film.

The concentration of the coating resin in the coating solution varies depending on the type of the resin and the degree of polymerization, but is generally preferably 20% by weight or less, particularly preferably 0.1 to 20% by weight. In the case of producing a time-eluting coated fertilizer, the coating resin concentration in the coating solution is preferably 20% by weight or less. In particular, when producing a time-eluting coated fertilizer for a nursery box, the coating resin concentration is 1%. ~ 8% by weight is preferred. Moreover, when producing a sustained-release coated fertilizer, the coating resin concentration can be produced in the range of 0.1 to 20% by weight.

The above coating resin may be used in combination with an inorganic filler represented by talc, a surfactant and the like.
These are dissolved / dispersed or melted / dispersed in a solvent together with the coating resin, sent to a spray nozzle and provided for coating.

In the method for coating core material particles of the present invention,
A heated gas is supplied while spraying the coating liquid onto the core particles, thereby evaporating the solvent in the coating liquid and forming a coating resin film on the surface of the core particles.

The heating gas is not particularly limited as long as it is inert to the particles and the solvent. Specifically, air, nitrogen gas, helium gas, etc. can be exemplified,
In particular, when a spout tower is used, a recycled gas or the like obtained by partially removing the organic solvent in the coating liquid from the spout tower outlet gas can be exemplified.

The temperature of the heated gas is preferably 10 to 100 ° C. higher than the melting point of the coating resin, and particularly preferably 15 to 80 ° C. higher than the melting point of the coating resin. The temperature of the heated gas is 1 point lower than the melting point of the coating resin.
If the temperature has not reached 0 ° C. higher, the coating time will be longer, and it will be difficult to achieve the object of the present invention sufficiently. Further, when the temperature of the heating gas exceeds 100 ° C. higher than the melting point of the coating resin, the temperature difference from the fixed layer becomes too large,
For this reason, dew condensation of the solvent easily occurs in the jet tower.

By supplying a heated gas in this temperature range to the core particles during spraying of the coating liquid, the solvent in the coating liquid being sprayed can be efficiently vaporized, and the core particles are mixed with the solvent. The core material particles can be efficiently coated without being melted by the heat of vaporization. In this case, the temperature of the core particles is 10 to 5 times lower than the melting point of the coating resin.
It is preferable to control the temperature to be lower by 0 ° C., and it is particularly preferable to control the temperature to be lower by 10 to 40 ° C. As a matter of course, the temperature should be selected to be lower than the melting point of the core particles.

When the temperature of the core material particles is lower than the melting point of the coating resin by 1
When the temperature exceeds 0 ° C. lower, the core material particles or the coating resin tend to partially melt or the production time tends to be longer.
If the temperature of the core material particles is lower than a temperature lower by 50 ° C. than the melting point of the coating resin, the coating resin solidifies quickly, and it is difficult to form a uniform coating.

When a plurality of resins having different melting points are mixed and used as the coating resin, the melting point of the coating resin is based on the melting point of the resin having the largest content. When there are a plurality of resins having the same content, the melting point of the resin having the highest melting point is used as a reference.

The present invention will be further described by taking as an example a case where urea is used for the core material particles and the core material particles are coated with polyethylene.
In this case, the temperature of the heating gas can be 70 to 250 ° C., but it is particularly preferable to set the heating gas temperature to 130 ° C. or higher because the coating time can be greatly reduced. The temperature of the core particles when supplying the heating gas while coating the core particles by spraying the coating liquid onto the core particles,
It is usually preferable that the temperature be equal to or higher than the solution gelation temperature of the coating resin in the coating liquid and equal to or lower than the melting points of the coating resin and the core material particles. If polyethylene is used as the coating resin, 60
~ 90 ° C is preferred. By adjusting the coating liquid supply rate and the supply rate of the heated gas, the core material particle temperature can be controlled within the above temperature range.

As a device used for carrying out the method for coating core material particles of the present invention, a known granulating device, coating device and the like can be appropriately used. As these devices, specifically,
A mixing and stirring device using a stirring blade such as a Henschel mixer or a Nauta mixer, a device such as a rotary drum type coater, a rotary pan type coater, a rotary drop type coater, etc., a device for mixing and stirring by rotating itself, mixing by applying vibration Examples include a vibrating fluidizing device for stirring, a Wurster-type or jet-type coating device for blowing and mixing and stirring particles, and a fluidized bed type coater for floating and flowing particles.

Of these, the jet-type coating apparatus using a jet tower is a suitable apparatus to be used in practicing the present invention because of the uniformity of the obtained film and the suitability for mass processing. .

The method of the present invention will be further described below using a jet type coating apparatus using a jet tower.

FIG. 1 shows an example of the configuration of a core particle coating apparatus which can be used in the coating method of the present invention. In FIG. 1, reference numeral 2 denotes a vertically installed jet tower. The main part of the jet tower 2 is constituted by a cylindrical tank main body 4.

The shape of the tank main body 4 is not particularly limited, and the shape of the horizontal section may be circular or polygonal. However, from the viewpoint of uniformity of circulation of the particles in the tank main body 4, it is preferable that the cross section of the tank main body 4 has a circular shape.

A cylindrical guide tube 6 is attached to the inside of the tank main body 4 by fixing means (not shown).

The shape of the guide tube 6 is not limited to a cylindrical shape, but may be a hole formed in a pipe or a wire mesh formed in a cylindrical shape. The shape and material of the guide tube 6 are not particularly limited. However, if it is desired to minimize damage to the coating at the time of coating, a smooth pipe without holes or protrusions, or a fluororesin is applied to the inner surface of the pipe. It is preferable to use a lining. The guide tube 6 is fixed or suspended in the tank main body 4 above the throttle unit 10 with the axial direction of the guide tube 6 being vertical.

The lower part of the tank main body 4 has an inverted conical bottom part 8 whose inner diameter is formed gradually smaller toward the bottom, and penetrates the lower end side of the bottom part 8 and has a narrower part 10 having a smaller diameter than the tank main body 4. Is formed. The orifice section 10 may be configured so that various orifice plates or venturis can be inserted separately.

One end of an extraction pipe 12 is connected to the restricting portion 10, and the other end side is a coating particle extraction port 16 through an on-off valve 14. One end of a gas supply pipe 18 is connected to the extraction pipe 12, and the other end of the gas supply pipe 18 is connected to a blower 22 via a gas heater 20 in the middle. As a result, the gas supplied from the blower 22 is heated by the gas heater 20 and then jetted into the tank main body 4 through the throttle unit 10. In this case, the temperature of the gas ejected into the tank main body 4 is set to a temperature higher by 10 to 100 ° C. than the melting point of the coating resin. Reference numeral 24 denotes a flow meter interposed in the gas supply pipe.

A spray nozzle 26 is provided near the center of the throttle unit 10. The spray nozzle 26 is connected to the throttle unit 1.
It suffices if it is in the vicinity of the throttle unit 10 along the central axis direction of 0, and may be a position higher or lower than the throttle unit 10. The position and shape of the spray nozzle 10 are appropriately determined depending on the properties of the spray liquid, operating conditions, and the like.

One end of a coating liquid supply pipe 30 provided with a coating liquid supply pump 28 is connected to the spray nozzle 26, and the other end of the coating liquid supply pipe 30 is connected to a coating liquid preparation tank 32.
Connected to. The coating liquid prepared in the coating liquid preparation tank 32 is supplied to the coating liquid supply pipe 30 by the coating liquid supply pump 28.
Through the spray nozzle 26 and then sprayed into the tank body 4. Reference numeral 34 denotes a steam heating jacket.

Numeral 36 denotes a particle input port formed in the tank main body 4 through which particles are supplied into the tank main body 4.
The spouted layer 37 is formed, and the particle surface is coated with a coating. In this case, the particles are cooled by the heat of vaporization of the solvent in the coating liquid, and the particle temperature is controlled to be lower by 10 to 50 ° C. than the melting point of the particles. Control methods include gas temperature,
This is performed by controlling the operating conditions of the coating apparatus such as the gas flow rate and the particle input amount. 38 is a particle inlet valve, and 39 is particles.

Reference numeral 40 denotes a discharge pipe attached to the upper wall 42 of the tank body 4, through which gas in the tank body 4 is discharged to the outside. Reference numeral 44 denotes a particle accumulation layer formed by accumulating particles that have dropped on the peripheral edge portion 46 of the jet part.

The gas flow velocity in the throttle unit 10 is determined by the amount of gas ejected and the throttle diameter. Further, the gas flow velocity in the guide tube 6 can be calculated by the same method. It is preferable that the distance between the guide tube 6 and the throttle unit 10 be selected in a range that does not hinder the circulation of the particles. The diameter of the guide tube 6 is preferably 1.2 to 4.0 times, more preferably 1.5 to 3.0 times the diameter of the main hole of the narrowed portion. In the present invention, the throttle unit 1
The flow rate of the gas at 0 and the flow rate of the gas in the guide tube are not particularly limited, but in order to stabilize the quality, when the inert gas is sent from the throttle unit 10 into the apparatus, Gas flow rate from 20 to 70m
/ Sec, and a method of adjusting the flow velocity of the gas in the guide tube 6 to 0.5 to 3 times the terminal velocity of the circulating particles to perform coating is recommended.

In the above description, the particle coating apparatus having the jet tower provided with the guide tube 6 in the tank main body 4 has been described, but the present invention is not limited to this. The present invention includes a particle coating apparatus having a spout tower without a guide tube. In this case, the above description is similarly applied.

Further, in the method of coating the core material particles of the present invention, this can be used as it is as a granulation method.
The coating method of the present invention includes a granulation method.

[0050]

The present invention will be specifically described below with reference to examples and comparative examples. In the following examples,% is by weight unless otherwise specified.

Examples 1 to 13 and Comparative Examples 1 to 4 (Production of Time-Eluted Coated Fertilizer) An example of the production of time-eluted coated fertilizer will be described with reference to the flow sheet of FIG. Tower diameter 60
0 mm, height 5000 mm, air outlet diameter 154 mm,
The heated gas (air) was supplied from the lower part to the upper part into the jet tower 2 having a cone angle of 50 degrees. Blower 2
After the air was blown using 2 and passed through the orifice flow meter 24, it was heated to a high temperature by the heater 20 to obtain a heated gas, which was supplied to the jet tower 2 as described above. After passing through the jet tower 2, the heated gas was discharged from an exhaust gas discharge pipe 40 provided at the upper part of the jet tower 2. 140 kg of core material particles having an average circularity coefficient of 0.7 or more are injected into the inside of the jet tower 2 in which the heated gas is circulated from the core material inlet 36 provided on the side surface of the jet tower 2. , FIG.
The core material particles 39 were caused to flow as shown in FIG.

During the coating operation, the flow rate of the heated gas and the temperature of the heated gas need to be appropriately adjusted for each sample. The heating gas flow rate was adjusted while measuring with the orifice flow meter 24. The heated gas temperature was adjusted while measuring the gas temperature with the thermometer T1, the particle temperature with the thermometer T2, and the exhaust gas temperature with the thermometer T3. In the present example and the comparative example, the test was performed at a flow rate (orifice flow meter 24) of 600 to 1400 m ³ / hr and a gas temperature (thermometer T1) of 100 to 180 ° C.

Table 1 shows the composition of the timed elution type coated fertilizer produced.

Each component of the coating material composition shown in Table 1 and toluene as a solvent are charged into the coating solution preparation tank 32, and mixed and stirred to form a coating solution in which the coating materials shown in Table 1 are mixed and dissolved. 33 was obtained. Using the pump 28,
The coating liquid 33 is applied to the spray nozzle 26 which is a 2 mm full-fluid type one-fluid nozzle installed at the lower part of the jet tower 2.
Was transported at a flow rate of 600 to 1100 kg / h, and sprayed and sprayed on the flowing core material particles 39. At this time, the preparation tank 32 is controlled so that the temperature of the coating liquid 33 does not become 80 ° C. or lower.
And the piping from the preparation tank 32 to the spray nozzle 26 was made into a double structure, and steam was passed through the inside of the double structure to transport the coating liquid while heating it. The PE used
Was 107 ° C., and the melting point of EVA was 77 ° C.

[0055]

[Table 1] The spraying of the coating liquid is carried out at the temperature (T2) of the flowing core material particles 39.
Is started at the time when the temperature reaches a predetermined temperature, spraying is performed for a predetermined time, and then drying is performed.
2 was stopped, and the coated core material particles 39 were discharged from the extraction port 16 at the lowermost part of the spout tower 2.
3. Examples 1 to 13 and comparative products 1 to 4 of granular time-eluting type coated fertilizers shown in Comparative Examples 1 to 4 were obtained. (Dissolution test) Each 10 g of the time-dissolved coated fertilizer (Examples 1 to 13 and Comparative products 1 to 4) obtained in the production of the time-dissolved coated fertilizer was immersed in 200 ml of water and allowed to stand at 25 ° C. . After a predetermined period, remove the fertilizer from the water,
The amount of fertilizer components eluted in water was quantitatively analyzed. After the measurement, the fertilizer was placed in 200 ml of fresh water and allowed to stand at 25 ° C. After a lapse of a predetermined period, a quantitative analysis of fertilizer components was performed in the same manner. This operation was repeated, and the relationship between the total dissolution of the fertilizer components eluted in water and the number of days was graphed to prepare a dissolution rate curve. The result is shown in FIG.

The number of days from the start of the immersion to the elution of 10 wt% (initial elution suppression period) was defined as “D1”, and the number of days from the start of immersion to the 80 wt% elution (elution period) was defined as “D2”. Furthermore, the number of days (elution period) from the start of immersion to the 80 wt% elution was defined as “DT”. Table 2 shows the results. In the example, since the heating gas temperature was higher than that of the comparative example, the manufacturing time was shorter than that of the comparative example. In addition, “(D1-5)
As is evident from the results of the “elution rate on the day”, the “elution rate on the D1-5 day of the working product” is “D1-5 of the working product” of the comparative product
Day elution rate ”, and the initial elution was suppressed.

[0057]

[Table 2] (Adjustment of compound fertilizer for cucumber cultivation) Nutrient demand curve of the cucumber (variety: Aso midori) in the open-field cultivation of cucumber (variety: Aso midori) in Minamata-shi, Kumamoto from the sowing to the harvest (the nutrient absorption pattern) Was determined from the soil nutrient supply curve during the cultivation period (the above-mentioned soil nutrient supply at each time period) and the nutrient absorption curve of the cucumber (the above-mentioned seasonal nutrient absorption amount) during the cultivation period measured in the previous year. The basic data used to obtain these curves is the prototype data of the same crop conducted in the same area last year. The nutrient demand curve of the cucumber obtained in the previous year thus obtained is shown in FIG.

Next, the time-dissolved coated fertilizer-executable product 2 and the product 10 were combined to obtain a compound fertilizer A having an elution curve close to the nutrient requirement curve. Fig. 2
Based on the elution curve of the described working product 2 and working product 10,
95: 5, 90:10... 5:95 The composition ratio is changed every 5 units, and virtual elution curves obtained from the respective composition ratios are drawn. From these, the elution curve most similar to the nutrient requirement curve is determined. The composition ratio to have was chosen. As a result, compound fertilizer A
It was found that the combination of time-eluting coated fertilizers 2 and 10 in a ratio of 45 to 55 was most suitable. The dissolution curve of the compounded fertilizer A of this combination was taken as the dissolution curve of the compounded fertilizer of Example, which is shown in FIG. The nutrient absorption curve is a curve incorporating a temperature change during the cultivation period (range of about 18 ° C. to 32 ° C.). Since the average temperature during the cultivation period is approximately 25 ° C., a dissolution curve at 25 ° C. is described. FIG. 2 is used as a reference for specifying the composition ratio. Similarly, the time-dissolved coated fertilizer-executed product 2 and the comparative product 2 were combined to obtain a compound fertilizer B having an elution curve close to the nutrient requirement curve. As for the compound fertilizer B, it was found that a combination of the time-eluting type coated fertilizer-executable product 2 and the comparative product 2 in a ratio of 50 to 50 was most appropriate. The dissolution curve of the compound fertilizer B was taken as a comparative compound compound fertilizer elution curve, and is shown in FIG.

FIG. 3 shows that in the compound fertilizer A, which is the compound fertilizer according to the present invention, the initial elution is extremely low, and the elution curve is very similar to the nutrient requirement curve of cucumber. You. On the other hand, in the compound fertilizer B, the suppression of the initial elution is insufficient, and the elution curve thereof is almost similar to the cucumber nutrient requirement curve, but the elution curve in the initial stage is clearly different. (Cucumber cultivation test using compound fertilizer) Compound fertilizer A and compound fertilizer B in a field in Fukuro (place name), Minamata City, Kumamoto Prefecture
A cucumber cultivation test was carried out using cucumber. The cultivation test was performed in three types of cultivation formats: a conventional plot test based on a normal agricultural work format, an experimental plot test using the compound fertilizer A, and a comparative plot test using the compound fertilizer B. Details of each test are shown below. Conventional plot test With respect to 100 ml of seedling cultivation soil containing no fertilizer prepared in advance, nitrogen component (N
Component, hereinafter abbreviated as N. ) 10 mg, phosphorus (P ₂ O ₅ component,
Hereinafter, it is abbreviated as P. ) 10 mg and 10 mg of a potash component (K ₂ O component, hereinafter abbreviated as K) mixed with a seedling culture material 400
ml into a 10 cm diameter plastic pot, and then seeded with one cucumber seed (variety: Aso midori)
Furthermore, cover the seedling cultivation soil on top of it, and
Seedlings were raised in plastic pots until October 10. After the seedling raising in the plastic pot was completed, the seedlings were transplanted to the field at a density of 1800 trees / 10a, and cultivation in the field was started. After that, harvesting of the main stem was started on July 5, harvesting of side branches was started on July 26, and harvesting was completed on September 19, and the cultivation was completed.

The seedlings are transplanted to a field, and 14% of N and 1% of P are used as fertilizer components between the time when the seedlings are planted in the field and before the harvest.
The advanced chemical fertilizer containing 4% and 14% K was fertilized in four times. The amount of fertilizer applied was N-P-K in the field 1 after four fertilizations.
It adjusted so that it might become 15Kg-15Kg-15Kg per 0 ares. Example section test For 100 ml of seedling cultivation soil containing no fertilizer prepared in advance, 10 m of P was used as a fertilizer for raising seedlings.
g, K 10mg mixed with 400ml of seedling cultivation soil material,
An amount of the compound fertilizer A in which the amount of N present in the compound fertilizer A is 8.33 g (corresponding to 15 kg of N per 10 ares in a field).
And stirred well and filled into a 10 cm diameter vinyl pot. One cucumber seed (variety: Aso midori) was sown thereon, and the seedling cultivation soil was covered thereon, and seedlings were raised in a plastic pot from April 20 to May 10. After the seedling raising in the vinyl pot was completed, the seedlings were transplanted to the field at a density of 1800 trees / 10a, and cultivation in the field was started. Thereafter, harvesting of the main stem was started on July 5, harvesting of side branches was started on July 25, and harvesting was completed on September 19, and the cultivation was completed.

The seedlings are transplanted to a field, and 14% of P and 1% of K are used as fertilizer components between the time when the seedlings are planted in the field and before the harvest.
The advanced chemical fertilizer containing 4% was fertilized in four times. Fertilization amount is 4 times fertilizer PK per 10 ares field,
It was adjusted to be 15 kg-15 kg. Comparative example plot test For 100 ml of seedling cultivation soil containing no fertilizer prepared in advance, 10 m of P was used as a fertilizer for raising seedlings.
g and K were mixed with 400 ml of the seedling culture material mixed with 10 mg of the fertilizer B, and the fertilizer B was thoroughly mixed with an amount of the fertilizer B of 8.33 g (N per 15 areal fields corresponding to 15 kg), and the diameter was 10 cm. Filled in a plastic pot of the type. Thereafter, one cucumber seed (variety: Aso midori) was sown, and the seedling cultivation soil was covered thereon, and seedlings were raised in a plastic pot from April 26 to May 6. After the seedling raising in the plastic pot was completed, the seedlings were transplanted to the field at a density of 1800 trees / 10a, and cultivation in the field was started. After that, harvesting of the main stem was started on July 6, harvesting of side branches was started on July 25, and harvesting on September 19 was completed.

The seedlings are transplanted to the field, and 14% of P and 1% of K are used as fertilizer components between the time when the seedlings are planted in the field and before the harvest.
The advanced chemical fertilizer containing 4% was fertilized in four times. Fertilization amount is 4 times fertilizer PK per 10 ares field,
It was adjusted to be 15 kg-15 kg.

As described above, N was fertilized in the conventional plot, and cucumber was cultivated without N in the comparative plot and the experimental plot.

As a result, no germination occurred in the comparative example test (germination rate: 0%). This is apparently due to excessive elution of the fertilizer components at the early growth stage. As is clear from the elution curve of the mixed fertilizer of the comparative example in FIG. 3, the initial elution of the mixed fertilizer B was not sufficiently suppressed, and the excessive elution caused a concentration hindrance to cucumber seeds.

On the other hand, the germination rate was 96% in the test in the example group, and the germination rate was 97% in the conventional test, indicating that the germination rate was almost as good.

In addition, the harvest index in the experimental test was also
It is 103 for the yield of the customary zone, which is 100,
The yield was comparable to the conventional test in which N topdressing was performed. As described above, it was found that even in the test in the example plot, even if the fertilization was reduced by about half of that in the conventional plot test (conventional agricultural work), an equivalent or higher yield could be obtained. By using the cultivation method of applying the compound fertilizer of the present invention at the same time as sowing, labor saving of the work and the use efficiency of the fertilizer can be greatly improved.

[0067]

According to the method of coating core particles of the present invention, the temperature of the heated gas is set to a temperature higher by 10 to 100 ° C. than the melting point of the coating resin, so that the solvent in the coating liquid can be vaporized efficiently. The coating amount is large. In addition, since the core material particles are cooled by the heat of vaporization, the core material particles do not melt, so that the resin coating can be reliably coated,
Further, it is possible to prevent the particles from accumulating and melting and solidifying in the coating apparatus. For this reason, the operation of the apparatus is stable, and a large amount of coated particles can be stably manufactured. Therefore, in the case of producing a time-eluting type coated fertilizer using the present coating method, the obtained coated fertilizer has a stable elution, and in particular, once the coated fertilizer has a stable initial elution suppression period determined by the coating composition. In addition, it can be manufactured in large quantities. When cultivating a crop using this coated fertilizer, especially at the start of seedling raising or at the time of sowing or transplanting to the field, the whole amount of the pesticide components to be applied and applied during the cultivation period, or most of them are applied at once. When used in a cultivation method, cultivation can be performed without causing concentration disturbance due to fertilizer. Furthermore, by applying this method, the production efficiency of fertilizers other than those for raising seedlings can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an example of the configuration of a core particle coating apparatus used for carrying out the present invention.

FIG. 2 is a graph showing a dissolution rate curve of a time-dissolved coated fertilizer.

FIG. 3 is a graph showing a nutrient demand curve of cucumber and an elution curve of a compound fertilizer.

[Explanation of symbols]

 2 Jet Tower 4 Tank Main Body 6 Guide Tube 8 Bottom 10 Restrictor 20 Gas Heater 22 Blower 26 Spray Nozzle 32 Coating Liquid Preparation Tank

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C05G 3/00 103 C05G 3/00 103

Claims (8)

[Claims] A core for coating the surface of a core particle with a coating resin by supplying a heating gas while spraying a coating solution obtained by dissolving a coating resin in a solvent onto the core particle and drying the solvent of the coating solution. A method of coating core particles, wherein the temperature of the supplied heated gas is maintained at a temperature higher by 10 to 100C than the melting point of the coating resin. 2. The core according to claim 1, wherein the temperature of the core particles supplying the heating gas while spraying the coating liquid onto the core particles is maintained at a temperature lower by 10 to 50 ° C. than the melting point of the coating resin. Method of coating material particles. 3. The method for coating core particles according to claim 1, wherein the core particles are jetted by supplying a heated gas. 4. The method for coating core particles according to claim 1, wherein the coating resin is a polyolefin resin. 5. The method for coating core particles according to claim 1, wherein the solvent is perchlorethylene, trichlorethylene, octane, or toluene. 6. The method for coating core particles according to claim 1, wherein the core particles are fertilizer particles or pesticide particles. 7. A coated fertilizer or a coated pesticide having a timed elution type elution function, which is obtained by the method for coating core material particles according to claim 6. 8. A method for cultivating a crop, comprising using the coated fertilizer or the coated pesticide according to claim 7.