JP2642874B2 - Method for producing coated fertilizer and product thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an improved coated water-soluble fertilizer and its product.
More specifically, the present invention granulates a water-soluble fertilizer, and coats the surface with a semi-permeable or impermeable film,
In producing slow-release fertilizers, biodegradable substances, especially finely ground fir husks, together with fertilizers, are used as fillers to facilitate granulation of fertilizers and matrices for controlling the rate of fertilizer dissolution. The present invention relates to a method for producing a coated water-soluble fertilizer which is easy to control the dissolution rate, and a product thereof.

[0002]

2. Description of the Related Art In general, water-soluble fertilizers, when fertilized, have a quick effect, but do not have a long-lasting effect, and a considerable part of the fertilizer is wasted due to leaching into the ground. is there. Furthermore, the required amount of fertilizer is not necessarily applied at the time when the crop is needed, and the use efficiency can be said to be considerably low. By the way, it is expected that the fertilizer efficiency will be increased if the amount of fertilizer required by the crop can be supplied at the required time. Therefore, in recent years, development research aimed at slowing or slowing the fertilizer effect by changing the physical shape of the fertilizer has been actively conducted.

[0003] Means for slowing / slowing the fertilizer include physical means, which are further classified into two. One is a method in which a matrix (paraffin, asphalt, etc.) is added to the water-soluble fertilizer particles and granulated or formed to suppress the elution of components through gaps in the matrix. The other is to coat the surface of the granular water-soluble fertilizer with a coating made of semi-permeable or impermeable coating material such as resin or sulfur, and gradually elute the components by diffusion through pinholes and cracks in the coating. By doing so, the sustainability of the fertilizer effect is enhanced.

[0004] The former is a matrix fertilizer (Matrixed Fertilizer).
) And the latter are called coated fertilizers (for example, Handbook of New Polymer Materials (1989),
5.13.3 Slow release fertilizer, P.C. 353, edited by The Society of Polymer Science, Maruzen Co., Ltd., Symposium on Fertilizers Aiming for the 21st Century (1989), p. 111; Development on coated fertilizer, P.M. 127; Development of coated fertilizer (Ceracoat) 133; microcapsules (functions and applications) centered on coated fertilizers-sulfur coating (SC) (199)
1), 2.5.2 Fertilizer, P.I. 189, Japanese Standards Association].

Among them, the former molded fertilizer (Matrixed
Fertilizer) has the advantage that it is easy to mass-produce fertilizers with uniform elution, but requires a larger amount of matrix (paraffin, asphalt, etc.) than coated fertilizers that process only the surface, There is a drawback that it is difficult to make a slow product, and it has not been commercialized.

On the other hand, the latter coated fertilizer (Coated Fertilize)
r) has the advantage that the dissolution rate can be controlled by the type and thickness of the coating material, but the cost increases depending on the coating material, and the coating material does not decompose in the soil, adversely affecting the physicochemical properties of the soil. Have the disadvantages.

As described above, conventionally, a fertilizer formed by adding a matrix (paraffin, asphalt, etc.) to water-soluble fertilizer particles and granulating or shaping the same and a coating material such as resin directly on the surface of the granulated water-soluble fertilizer. Although various fertilizers coated with a film comprising have been proposed, a product which can surely overcome the above-mentioned disadvantages has not yet been developed.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned drawbacks of conventional slow- and slow-acting fertilizers in such a situation. It is an object of the present invention to provide a novel method for producing a coated fertilizer capable of efficiently and economically producing a new type of coated fertilizer that combines the advantages of both, and a product thereof.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, together with fertilizer components, have been produced in large quantities as biologically degradable substances, particularly agricultural wastes. The obtained fir hulls are granulated using a filler for facilitating granulation of the fertilizer component and a matrix for controlling the dissolution rate of the fertilizer component, and the surface of the particles obtained here is semi-permeable to It has been found that the object can be achieved by coating with a coating made of a water-impermeable coating material, and the present invention has been completed based on this finding.

That is, the present invention provides a slow-release fertilizer having a long-lasting fertilizer effect by granulating a water-soluble fertilizer and coating the surface thereof with a coating made of a semi-permeable or impermeable coating material. In doing so, together with the fertilizer component, a biodegradable substance, particularly a finely ground fir shell, is used as a bulking agent that facilitates granulation of the fertilizer component and a matrix that controls the elution rate of the fertilizer component. It is intended to provide a method for producing a coated fertilizer characterized by being granulated using the same and a product thereof.

The fertilizer component coated in the present invention comprises:
A water-soluble fertilizer component essential for the growth of ordinary crops, for example, nitrogen fertilizer, phosphate fertilizer and potassium fertilizer, and more specifically, ammonium sulfate, urea, ammonium dihydrogen phosphate, potassium chloride Etc. are exemplified as typical ones. In particular, nitrogen fertilizers are susceptible to leaching and denitrification by microorganisms in soil,
The substance to be coated is a general substance.

In the present invention, the fertilizer component is granulated by adding a binder such as a soluble starch or a water glass solution, and the surface thereof is further synthesized with a synthetic polymer such as ethyl cellulose or polystyrene or an aliphatic polyester or lactic acid polymer. Coated with a semi-permeable or non-permeable membrane composed of biodegradable polymers such as to produce a coated fertilizer with a long-lasting fertilizing effect. It is important to use a readily degradable substance as a bulking agent for facilitating granulation of the fertilizer component and a poorly soluble substance (matrix) for promoting the sustained release of the fertilizer component. In this case, it is preferable to use the biodegradable polymer material as the coating material, but the biodegradable polymer is not particularly limited, and is a material that is rapidly decomposed by microorganisms in nature. If so, it can be used regardless of its type.

[0013] The extendable material for facilitating the granulation of the fertilizer component and the biodegradable substance used as a poorly soluble substance (matrix) for promoting the sustained release of the fertilizer component include, among others, appropriate ones. Fir hulls finely ground to a particle size or those having the same effect are preferably used. In this case, the fir husk used in the method of the present invention can be used regardless of its type, as long as it is a normal fir husk or the same as the fir husk, and in particular, the fir husk is an agricultural waste. And is extremely inexpensive, and is advantageous in terms of the price, which is said to be the greatest difficulty of molded and coated fertilizers.

According to the present invention, a biodegradable substance, together with a fertilizer component, is used as an extender for facilitating granulation of the fertilizer component, and for promoting the sustained release of the fertilizer component. The use as a poorly soluble substance (matrix) has the advantage that the coating amount of a high-cost coating material, which has hitherto been the greatest problem of coated fertilizers, can be greatly reduced without lowering its quality. Also, the fir shell is
It is a biologically easily decomposable substance, and its components are also used as fertilizers. Most of the matrices (paraffin, asphalt, etc.) used in conventional molded fertilizers are biologically indegradable substances. Considering the above, it is a so-called earth-friendly substance, and is also effective from the viewpoint of global environmental protection.

Next, the manufacturing method of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a production process of a coated fertilizer according to the present invention. A powdery water-soluble fertilizer to be coated with a coated fertilizer and a fir shell finely pulverized by a sample mill are prepared, sufficiently mixed in an appropriate ratio, and used as a van binder, for example, a soluble starch aqueous solution or water. Knead in a kneader while spraying a glass solution or the like. Next, short and thin pellets are formed by using an extruder, and then granulated by, for example, a rotating disk type granulator.

After granulation, the granules are dried in an oven and then coated. The coating is performed, for example, in a fluidized bed type coating apparatus. In this case, the coating material is, for example, ethyl cellulose, polystyrene or the like. And a biodegradable polymer of an aliphatic polyester. The production process in FIG. 1 shows a preferred example of the method for producing a coated fertilizer according to the present invention. In the production process, mixing, granulation, and coating of the fertilizer components are usually performed. The method can be performed by a method, and an appropriate method and apparatus can be used.

[0017]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples. EXAMPLES The preparation method of the coated granular material is as follows.
That is, ammonium sulphate (ammonium sulfate) was used as a water-soluble fertilizer, and finely ground fir shell was used as a filler and matrix, respectively, and the mixture was sufficiently mixed at a ratio of 9: 1 (fir husk: ammonium sulfate) to make the total weight 300 g. . Next, the mixture was mixed with about 19% aqueous 10% soluble starch as a binder.
The mixture was kneaded well in a kneader while spraying 0 ml. Next, the mixture was formed into thin and short pellets by an extruder, and then formed into granules having a diameter of about 0.5 to 2.0 mm by a granulator. After drying the granules at room temperature for 5 hours,
The product was dried in an oven at 65 ° C. for 24 hours.

The dried particles were coated with ethyl cellulose as a coating material. In this case, the ethyl cellulose used as the coating material was dissolved in dichloroethane at a concentration of 2 (w / v)% before use. The coating is
The bottom spray type fluid coating apparatus shown in FIG. 2 was used. A partition 1 is provided in the lower center of the fluidized bed, and the gas distribution plate 2 has a large opening ratio at the inner part of the diameter of the partition 1 and a small opening ratio at the outside. The dichloroethane solution in which ethyl cellulose is dissolved exits the spray nozzle 3 and is sprayed upward from the center of the partition 1. Coated granular material 4
Will stall after blowing up in the partition 1 with a high airflow velocity, fall outside the partition 1, and repeat the circulation again by the upward airflow. As a result, the granular material 4 to be coated is
Since the spray liquid adheres at a constant viscosity in the vicinity, a coated fertilizer with good continuity of the film is finally obtained.

FIG. 3 shows an example of the results of a dissolution test in water of the coated fertilizer prepared by the production method of the present invention. As is clear from the relationship graph between the elution rate and the elution time (days) in FIG.
When the coating material (ethyl cellulose) is coated in an amount corresponding to 7% of the weight of the coated granular material, 50%
It took about 3 days to achieve the elution rate of, after which the elution continued in small increments, reaching 70% after about 2 weeks.

On the other hand, 20% of the weight of the granular material to be coated
In the case of coating with an amount corresponding to the above, it took about 10 days to reach the dissolution rate of 50%, and then the dissolution continued gradually, and it took about one month to reach the dissolution rate of 70%.
From the dissolution test results obtained by changing the above items and the coating amount of the coating material, the dissolution rate in water of the coated fertilizer obtained by the production method of the present invention, the coating amount of the coating material, for example, It was found that even when the amount was reduced to a low level of 7% or less, it could be arbitrarily controlled by the coating amount.

[0021]

As described above in detail, according to the method for producing a coated fertilizer of the present invention, a biodegradable substance, particularly fir husk, which is an inexpensive agricultural waste, is combined with a fertilizer component. By using the filler as a bulking agent for facilitating granulation of the fertilizer component and a matrix for promoting the sustained release of the fertilizer component, it is possible to efficiently coat the water-soluble fertilizer and slow down its effect. It can be done economically.

Further, according to the present invention, it is possible to reduce the coating amount of the coating material in a coated fertilizer which has been required to be improved because it has a disadvantage such as adversely affecting the physicochemical properties of soil. , And even if the coating amount is reduced to a low level, a coated fertilizer capable of arbitrarily controlling the dissolution rate can be easily produced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a production process of a coated fertilizer according to the present invention.

FIG. 2 is a schematic view of a bottom spray type fluid coating apparatus used for coating a granular material to be coated in an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the results of a dissolution test in water of a coated fertilizer prepared by the production method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 partition 2 gas dispersion plate 3 spray nozzle 4 granular material to be coated

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsutoshi Yamada Hokkaido Industrial Technology Research Institute, Institute of Industrial Science and Technology, Ministry of International Trade and Industry (2-1) Shigenobu Tanaka Hokkaido Sapporo, Hokkaido 2-17-17-2, Tsukikanto, Toyohira-ku, Yokohama-shi Inside the Hokkaido Institute of Industrial Technology, Ministry of International Trade and Industry (56) References JP-A-48-90851 (JP, A) A) JP-A-62-26991 (JP, A) JP-A-63-25288 (JP, A) JP-A-3-197421 (JP, A) JP-A-50-142365 (JP, A) JP-B-48 −39546 (JP, B1)

Claims (3)

(57) [Claims] 1. A water-soluble fertilizer is granulated, and its surface is coated with a coating made of a semi-permeable or non-permeable coating material composed of a synthetic polymer or a biodegradable polymer, so that the durability of the fertilizer effect can be maintained. In producing a high coated fertilizer, together with the fertilizer component, a finely ground fir husk is used as an extender for facilitating granulation of the fertilizer component and a sparingly soluble substance for promoting the sustained release of the fertilizer component. use as (matrix), these
Add a van binder, mix, extrude and granulate
The dried particles are applied to the fluid coating device.
A method for producing a coated fertilizer, characterized in that a coating material is coated with a coating material . 2. The method for producing a coated fertilizer according to claim 1, wherein the coating material is a synthetic polymer such as ethyl cellulose or polystyrene or a biodegradable polymer such as an aliphatic polyester or lactic acid polymer. 3. A coated water-soluble fertilizer obtained by the production method according to claim 1, wherein the dissolution rate is easily controlled.