JPH06279161A - Preparation of granulated fertilizer with delayed action - Google Patents

Abstract

PURPOSE: To improve a slowly-acting effect by basically coating a granular fertilizer with a soln. prepd. by dissolving rosin, rosin deriv. and a first high-polymer material into an org. solvent, then subjecting the fertilizer to protective coating with a soln. prepd. by dissolving a second high-polymer material into the org. solvent.

CONSTITUTION: The basic coating material soln. of a concn. 0.5 to 50% is prepd. by adding 0 to 20% first high-polymer material, such as ethyl cellulose to a mixture composed of 30 to 100 wt.% (hereafter %) rosin, such as gum rosin, and 0 to 70% rosin deriv., such as ester of rosin and dissolving the mixture into the org. soln. The granular fertilizer is coated with the soln. at a rotating speed of 10 to 30 rpm/min, a spraying pressure of 1 to 3 kg/cm² and 20 to 70°C by using a fan type rotary coating machine in such a manner that a coating rate of 2 to 40% is attained and thereafter, the fertilizer is dried. Next, the basic coated granular fertilizer is coated with the protective coating material soln. of a concn. 0.5 to 50% prepd. by dissolving the second high-polymer material, such as nitrocellulose, into the org. solvent under similar conditions by using the same coating machine in such a manner that the coating rate of 0.2 to 30% is attained, and thereafter the fertilizer is dried, by which the slowly-acting granular fertilizer is obtd.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method in which a polymeric substance is added to rosin or a rosin derivative, and a basic coating material dissolved in an organic solvent is sprayed onto granular fertilizer for coating, and then a protective coating is applied thereon. Thus, the present invention relates to a method for producing a coated granular fertilizer, which facilitates handling and storage and improves the delayed-effect effect.

[0002]

2. Description of the Related Art Most of the chemical fertilizers currently used are easily dissolved in water, so that the amount of fertilizer applied is large, and therefore the amount of fertilizer applied is large compared to the amount of fertilizer applied. There are problems such as low yield and waste of labor due to frequent fertilization. Therefore, in order to enhance the utilization efficiency of fertilizers and reduce the number of times of fertilizer application, there is an urgent need to develop economically slow-acting fertilizers in which fertilizer components are gradually eluted into soil and water.

The conventional methods for producing slow-acting fertilizers are roughly divided into new chemical substances by chemical reaction between fertilizers and other substances, and the substances are gradually decomposed after fertilization.
It can be divided into a chemical method of supplying the fertilizer component and a physical method of coating or impregnating with a suitable substance for slowing the dissolution rate.

In the chemical method, the strength of the chemical bond, the solubility, the decomposition rate, etc. are factors that determine the persistence of the fertilizer,
A typical example thereof is a combination product of urea and aldehyde (US Pat. No. 3,227,543), but it has a disadvantage that the production cost thereof is higher than that of other organic treating agents.

Among the physical methods, the method of mixing a fertilizer with a special substance has a simple manufacturing process, but it is difficult to reduce the content of the fertilizer component and control the elution rate of the fertilizer component by using the mixed substance. There is a problem in being put to practical use.

In addition, in the method for producing a delayed-acting fertilizer by coating, the elution rate of fertilizer can be easily adjusted by selecting the coating material, the fertilizer content can be increased, and the process is relatively economical. It is the most actively researched because it can be manufactured in.

Sulfur coated fertilizer developed by US TVA (US Pat. No. 3,295,950) and Archer-Daniels-Midland C
Osmocote (US Pat. No. 3,223,518), developed in o.), is an example of a representative coated fertilizer. However, when sulfur is used as a coating material, it has an advantage that the price is low, but it is difficult to control the elution rate of the fertilizer, and there is a drawback that sulfur is accumulated in the soil and the soil is acidified. Osmocoat is a multi-layered coating containing a copolymer of dicyclopentadiene and glycerol ester as the main component, and is excellent in quality, but high in price.
There is difficulty in recovering the organic solvent used.

In addition to this, Nutricote (Korean Patent Publication No. 8) using an olefin polymer
No. 2-2204) or an acrylate polymer (Japanese Patent Publication No. 64-03093) and no organic solvent is known.

On the other hand, metal oxides and silicates have been proposed as coating materials (Japanese Patent No. 59,137,386).
No.), since the silicate used as the main component of the coating material dissolves in water, it is difficult to expect a sufficient retarding effect. By coating with a silicate and then with a secondary coating with a polymer substance, the delayed effect is complemented (Korean Patent Publication No. 8).
No. 8-153) has a good slow-acting effect on the coating and has the advantage of not using an organic solvent, but on the other hand, it uses expensive latex as a coating material, so the manufacturing cost is high and the latex component remains in the soil. There is a disadvantage that it accumulates.

Besides these polymeric substances, wax has been proposed as a coating material which does not dissolve in water (US Pat. No. 3,232,237). It has the disadvantage that the wax content in fertilizer is very large. In order to supplement this, a method of mixing and melting wax and rosin and using it as a coating material (Japanese Patent Publication No. 59-35875) has been proposed. According to this method, paraffin wax or brand wax is used as a basic substance, rosin is mixed at 30-80% by weight, and the resulting mixture is melted and used as a coating material. Can be manufactured. However, when the rosin content is 80% by weight or more, the formation of pinholes in the coating is extremely severe, and it is difficult to form a uniform coating. The main cause of the formation of such a non-uniform coating film is that the wax and rosin must be melted and the coating process must be performed at a relatively high temperature.

[0011]

In the present invention, by developing a method of further coating a protective film on a base film made of rosin or a rosin derivative, the durability of the rosin film is remarkably increased and a delayed-acting effect is obtained. It is possible to produce a practical coated granular fertilizer having excellent properties, easy to handle and store.

The rosin derivative used for improving the physical properties of rosin itself can be roughly classified into two types.
One is synthesized by reacting with a double bond of abietic acid, and the other is synthesized by reacting with a carboxyl group.

The reaction utilizing a double bond may be, for example, a polymerizing reaction and a Diels-Alder reaction between a compound having a double bond such as maleic anhydride, and a reaction utilizing a carboxyl group. Is typically an esterification reaction with an alcohol or a reaction for producing a metal salt by a reaction with a metal. In the present invention, a rosin derivative obtained by a polymerizing reaction, Diels-Alder reaction and esterification reaction is used together with rosin as a basic coating material, and as a coating material for the protective film, it is dissolved in an organic solvent or made into an emulsion in water. It is possible to use high molecular substances.

The technical contents of the present invention will be described in detail below.

In the present invention, 0-20% by weight of the first polymer substance is added to a mixture of 30-100% by weight of rosin and 0-70% by weight of rosin derivative to obtain a mixture of 0.5-50% by weight. The base coating material dissolved in an organic solvent to form a solution was applied to the base fertilizer in an amount of 2 to 40% by weight based on the granular fertilizer, and then 0.5 to 50% by weight of the second polymer substance was added thereto. A method for producing a delayed-acting granular fertilizer, which comprises protectively coating an organic solvent solution or an emulsion solution so as to be 0.2 to 30% by weight with respect to the basic coated granular fertilizer.

Examples of the rosin that can be used in the present invention include gum rosin, wood rosin and tall oil rosin, and the effect of using gum rosin is most excellent.

The rosin derivative usable in the present invention includes rosin ester, polymerized or dimerized rosin, hydrogenated rosin, rosin reacted with maleic anhydride and maleic anhydride and glycerol or toluene. Examples include rosin reacted with diisocyanate. These have the effect of increasing the melting point of rosin and increasing the durability, especially of rosin reacted with maleic anhydride, maleic anhydride and a polyhydric alcohol such as glycerol or rosin reacted with toluene diisocyanate. The effect is excellent.

In the present invention, examples of the first polymer substance include ethyl cellulose, nitrocellulose, benzyl cellulose, polyvinyl acetate, polyacrylate, alkyd resin, and a copolymer of vinyl acetate and rosin. Addition of such a polymer substance increases the delayed effect and the durability, and is particularly excellent in the effect of ethyl cellulose, polyvinyl acetate, and a copolymer of vinyl acetate and rosin.

The solvent which can be used in the present invention may be any organic solvent capable of dissolving rosin,
For example, methanol, ethanol, isopropanol, t
-Butanol, benzene, methyl ether, methylene chloride, tetrahydrofuran, chloroform, acetone, methyl acetate, ethyl acetate, acetonitrile, trichloroethane, etc., especially alcohols,
Acetone and methyl ether are excellent.

Second used as protective coating in the present invention
Examples of the polymer compound include ethyl cellulose, benzyl cellulose, nitrocellulose, polyvinyl acetate, alkyd resin, a copolymer of rosin and vinyl acetate, a polymer of acrylates or styrenes, alone or in a mixture, and emulsion polymerized. In particular, nitrocellulose, a copolymer of rosin and vinyl acetate, has an excellent effect in increasing the durability of the coated granular fertilizer. These organic solvent solutions use alcohols such as ethanol, benzenes and methylene chloride or acetone as a solvent.

The method of coating the above-mentioned two types of coating materials on the granular fertilizer will be described in detail. First, the method of coating rosin as a basic coating material is a prior invention (Korean Patent Application No. 2).
No. 2,161, date of application December 4, 1991), which is as follows.

In the coating step, a fan type rotary coating machine is used to spray the coating liquid on the granular fertilizer. At this time, the rotation speed of the drum is 10-30 rpm / min, and the air pressure of the spray nozzle is 1-3 kg / cm. ^{2. The} temperature is maintained at 20-70 ° C.

After the coating is completed, the granular fertilizer is dried in the drum of the coater, at a temperature of 30-90.
C. and the drying time is 1 minute-2 hours. Since the solvent is an organic solvent having a high volatility and a low boiling point, the recovery is relatively easy, and no special heat treatment step is required, and the step is completed by recovering the solvent. If necessary, the coating step is divided into 1 to 10 times, and a coating material containing rosin and a rosin derivative as main components is performed so as to be 2 to 40% by weight with respect to the granular fertilizer, and a multi-layer coating having a delayed effect is obtained. It is also possible to produce fertilizer.

Next, in the step of coating the protective film, the same fan type rotary coating machine as that used for the rosin coating is used to spray and coat the coating liquid. The rotation speed of the drum is 10-30 rpm / min, the air pressure of the spray nozzle is 1-3 kg / cm ² , and the temperature is 20-70.
Keep at ℃. As in the case of the coating step in the previous step, the coating of the protective film can be carried out in 1-10 times if necessary so as to be 0.2-30% by weight with respect to the base-coated fertilizer. After this step is completed, the coated fertilizer particles are subjected to a drying step in the drum of the coater, the temperature at this time is 30-90 ° C, and the drying time is 1 minute-2 hours. When an organic solvent is used, the solvent is recovered as in the previous step, and when an emulsion solution is used, the solvent recovery step is not necessary. In any case, all steps are completed by the above-mentioned drying step without passing through a special heat treatment step.

[0025]

Industrial Applicability The coated granular fertilizer obtained by the simple steps as described above is coated with a protective film on the basic coating, whereby sticking, adhesion, coating damage and crushing between the coated fertilizer particles. Since there is no phenomenon, there are no problems during handling and storage, the elution rate of fertilizer components in water and soil is easy to control, and not only is the delayed-release effect excellent, but the fertilizer components gradually elute after elution. It has the advantage that it does not accumulate in the soil and decomposes into soil.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples. These examples show a part of the scope of the present invention, and the scope of the present invention is not limited by these examples.

Example 1 (Base coating) A fan type rotary coater was used to coat granular urea fertilizer with a particle diameter of 2.36-2.83 mm. A coating solution of 20% by weight of 100 g of gum rosin dissolved in 400 g of ethanol was coated with granular fertilizer at a temperature of 50 ° C., an air pressure of a spray nozzle of 1.5 kg / cm ² , and a spray rate of 2 ml / min. After the coating was completed, it was dried in a rotating drum at the same temperature for 10 minutes to obtain a base coating. In the case of a multi-layer coating, after the drying step of the primary coating is completed, the coating step is repeated in the same manner. The dissolution experiment was carried out after the drying step was completed, and in the case of the single-layer coated fertilizer, the dissolution rate after leaving it at room temperature for 1 day was also measured and compared.

The amount of fertilizer eluted was measured using high pressure liquid chromatography manufactured by Berrian. Table 1 shows the results of measuring the amount of fertilizer eluted by putting the coated fertilizer in water at 30 ° C.

[0029]

[Table 1]

Example 2 (basic coating) Gum rosin mixed with 30% by weight of a predetermined rosin derivative was dissolved in acetone to prepare a 20% by weight solution, and granular urea was prepared in the same manner as in Example 1. Fertilizer was coated so that the coverage was 1%. The fertilizer elution rate in water at 30 ° C is shown in Table 2.

[0031]

[Table 2]

Example 3 (Basic coating) A mixture of gum rosin with 10% by weight of a predetermined polymer was dissolved in methyl ether to prepare a solution with a concentration of 20% by weight. The granular urea fertilizer was coated in the same manner as in Example 1 so that the coverage was 11% by weight.
The dissolution rate of fertilizer in water at 30 ° C is shown in Table 3.

[0033]

[Table 3]

Example 4 (Coating with protective film) Coverage with a rosin base film 11.2% by weight
The urea fertilizer coated on was selected, and a protective film coating was applied. The coating solution is a solution of a predetermined polymer substance dissolved in ethanol at a concentration of 5% by weight, the fertilizer is coated at a temperature of 50 ° C., an air pressure of a spray nozzle of 1.5 kg / cm ² , and a spray rate of 2 ml / min. did.
After the coating was completed, the coating was dried in a rotary drum at the same temperature for 10 minutes, and was carried out once or in a necessary number of times so that the total coating rate was 1 to 5% by weight based on the basic coating urea fertilizer. Table 4 shows the results of measuring the amount of fertilizer eluted by putting the coated fertilizer in water at 30 ° C.

[0035]

[Table 4]

Comparative Example 1 (Durability test) A 30% by weight methanol solution of rosin was used as a base coating at a coverage of 10% by weight with a granular urea fertilizer and nitrocellulose on the base coating as a base coating urea fertilizer. Urea fertilizer with a protective coating of 2% by weight was placed in each vibrator (Model No. 1640 manufactured by Toyo Kagaku Co., Ltd.) and vibrated at a speed of 100 times / min for 5 minutes, and then the fertilizer elution rate in water at 30 ° C. was measured. did. The results are shown in Table 5.

[0037]

[Table 5]

Comparative Example 2 (Storability test) The coated granular urea fertilizer produced by the method of Comparative Example 1 was placed in a bag made of polyethylene film having a width of 25 cm and a length of 18 cm, 1 kg each, and the bag was sealed. A 50 kg weight was placed for 10 days.

At this time, the fertilizer coated only with rosin was
The phenomenon that the particles of the fertilizer adhered to each other was serious,
No such phenomenon was observed with fertilizers coated with rosin and overcoat. The fertilizer elution rate in water at 30 ° C is shown in Table 6.

[0040]

[Table 6]

Example 5 (Protective coating) A protective coating was applied to urea fertilizer having a coverage of the rosin base coating of 11.2% by weight. As the coating liquid, a 10 wt% emulsion solution of a predetermined polymer substance was prepared, and fertilizer was coated by the method of Example 4. The coverage is set to 3% by weight with respect to the urea fertilizer, and
Table 7 shows the elution rate of fertilizer in water at ℃.

[0042]

[Table 7]

Example 6 (Protective film coating) The predetermined base-coated fertilizers produced in Examples 2 and 3 were coated with a protective film by the method of Example 4. As the protective coating solution, a 10% by weight benzene solution of ethyl cellulose was prepared, and coating was performed at a coating rate of 2.5% by weight. Thirty
The fertilizer elution rate in water at ℃ is shown in Table 8.

[0044]

[Table 8]

Example 7 (Coating with protective film) Rosin was used as a base coating material, and the coverage was 1
N with a diameter of 2.04-3.16 mm coated with 0% by weight
-P-K compound granular fertilizer (15-15-15),
A protective film coating was applied. As the protective coating solution, a 5 wt% acetone solution of nitrocellulose was produced, and the fertilizer was coated with a protective film by the method of Example 4. Coverage is 5 for basic coated compound fertilizer
Table 9 shows the fertilizer elution rate of the fertilizer coated so as to have a weight percentage of 30% in water.

[0046]

[Table 9]

Example 8 (Protective film coating) Wood rosin and tall oil rosin were used as a basic coating material, and a granular urea fertilizer coated at a coverage of 10% by weight was coated with a protective film. As a protective coating solution, a 5% by weight solution of polyvinyl acetate in toluene was prepared, and the base coating fertilizer was coated by the method of Example 4. The coverage is set to 3% by weight with respect to the base-coated urea fertilizer, and the fertilizer elution ratio of the coated fertilizer in water at 30 ° C is shown in Table 10.

[0048]

[Table 10]

Front Page Continuation (72) Inventor Choi Toru Ji, 39-1 Shimogetsuya-dong, Seongbuk-gu, Seoul, Republic of Korea (72) Inventor 254, Incheon-dong, Lorihara-ku, Seoul, Republic of Korea 254 (72) Inventor Kim 639-15 Hokkaku-dong, Dobong-gu, Seoul, South Korea

Claims (6)

[Claims] 1. A mixture of 30-100% by weight of rosin and 0-70% by weight of rosin derivative, 0-20% by weight of the first.
After adding the polymer substance of 1) to the base coating material dissolved in an organic solvent to form a solution having a concentration of 0.5 to 50% by weight, the base coating material is added to the granular fertilizer at 2 to 40% by weight,
A 0.5-50 wt% organic solvent solution or emulsion solution of the second polymeric substance is then protectively coated on the base fertilized granular fertilizer in an amount of 0.2-30 wt%. A method for producing a slow-acting granular fertilizer. 2. The method for producing a delayed-acting granular fertilizer according to claim 1, wherein the rosin is selected from wood rosin, gum rosin and tall oil rosin. 3. A rosin derivative, a rosin ester, a polymerized or dimerized rosin, a hydrogenated rosin, a rosin reacted with maleic anhydride, and a maleic anhydride reacted with a polyhydric alcohol or toluene diisocyanate. The method for producing a slow-acting granular fertilizer according to claim 1, which is selected from rosins. 4. The method for producing a delayed-acting granular fertilizer according to claim 1, wherein the first polymer substance used as the base coating material is selected from ethyl cellulose, polyvinyl acetate, and a copolymer of vinyl acetate and rosin. 5. The second polymeric substance used as the protective coating material is selected from ethyl cellulose, benzyl cellulose, polyvinyl acetate, nitrocellulose, copolymers of vinyl acetate and rosin, and polymers of acrylates or styrenes. The method for producing the delayed-acting granular fertilizer according to claim 1. 6. The method for producing a delayed-acting granular fertilizer according to claim 1, wherein the base coating and / or the protective coating is performed a plurality of times to perform multi-layer coating.