JPH07215789A - Multilayer coated granular fertilizer and its production - Google Patents

Abstract

PURPOSE:To coat the surface of a granular fertilizer so as to freely control elusion of the fertilizer component and to coat the fertilizer in a good state without using an org. solvent which causes problems such as environmental pollution. CONSTITUTION:Granules of the fertilizer are primarily coated with a compd. essentially comprising wax having 60-120 deg.C melting point or a mixture of wax having 60-120 deg.C melting point with ethylene-vinyl acetate copolymer resin. Then the granules are secondarily coated with a compd. essentially comprising the reaction product of oil-modified alkyd resin and unsatd. oil having conjugate double bonds in the molecule. The kind of wax or mixture of wax and ethylene- vinyl acetate copolymer resin and the film thickness are changed to control the elusion rate of the fertilizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated granular fertilizer which controls the elution rate of the fertilizer by coating the surface of the granular fertilizer and a method for producing the same.

[0002]

2. Description of the Related Art Along with recent changes in the environment surrounding agriculture, agricultural materials have been required to have various functions. Some problems have been pointed out regarding the chemical fertilizers that are currently widely used,
It is required to solve them.

That is, most chemical fertilizers are water-soluble and fast-acting. Therefore, a large part of the dissolved fertilizer components is not absorbed by the crops, and is damaged by runoff, denitrification, etc., which not only lowers the utilization rate but also puts a burden on the ecosystem environment.

In the case where the fertilizer is frequently fertilized such as upland and horticultural crops and the growing environment is restricted, salt concentration disturbance may be caused in the case of ordinary chemical fertilizers, together with uneven sowing during fertilization. Many are seen.

Furthermore, the problems of a decrease in the number of agricultural workers and the aging of the population are increasing, and nowadays more labor-saving agriculture is required. Those with functions have been required.

In order to solve such problems, various fertilizer control type fertilizers have been proposed and put into practical use. One of the fertilizers for this purpose is coated fertilizer. This is a fertilizer in which the elution of the fertilizer components inside is controlled by coating the surface of the granular fertilizer with an organic or inorganic coating material. Above all, coated fertilizers using organic coating materials such as resins have a better elution control function, and are becoming the mainstream among coated fertilizers.

However, in the process of producing a coated fertilizer with an organic coating material using this resin or the like, an organic solvent is generally used to dissolve the coating material (resin), and therefore its toxicity and ignition It is necessary to pay sufficient attention and consideration to sex.

In recent years, with the increase of environmental problems, the use of organic solvents has been regarded as a problem in terms of solvent recovery and environmental pollution. On the other hand, as a method that does not use an organic solvent,
Although there is a method of using the coating material as a water emulsion, generally, a film formed from a water emulsion of resin is inferior in strength and permeability to a film produced using an organic solvent, and the fertilizer component is water-soluble. It is difficult to produce a coated fertilizer that can be sufficiently dissolved due to the fact that it dissolves due to the water content in the emulsion and impairs the performance of the membrane.In addition, the spinnability of the resin tends to cause blocking during production. There is also the problem of. Further, since the latent heat of vaporization of water is large, it takes time and a large amount of energy for drying, and it cannot be said that the productivity is necessarily high.

However, recently, a new method for solving these problems has been proposed (JP-A-5-4887). This is a method of using a coating material mainly composed of an oil-modified alkyd resin and an unsaturated oil having a conjugated double bond in the molecule.

It is described that according to the present method, a coated granular fertilizer can be obtained with high productivity without using an organic solvent having a problem of recovery and environmental pollution. However, since the coating material of this method contains alkyd resin as one of the main components, there is room for improvement in coating performance. That is, since the alkyd resin has a low glass transition temperature, it is inferior in water resistance and further has a large shrinkage during curing, resulting in poor film formability, uneven film formation, and low water permeability.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have developed a coating material which is solvent-free and has improved water resistance and film forming property of alkyd resin and excellent performance. Heading The invention has been reached.

That is, according to the present invention, the surface of the granular fertilizer is reacted with a primary coating layer composed mainly of wax having a melting point of 60 to 120 ° C., an oil-modified alkyd resin and an unsaturated oil having a conjugated double bond in the molecule. A coated granular fertilizer characterized by being coated with a secondary coating layer containing a product as a main component, which contains a compatible material of a wax having a melting point of 60 to 120 ° C. and an ethylene-vinyl acetate copolymer resin as a main component. A multi-layered granular fertilizer characterized by being coated with a primary coating layer, a secondary coating layer containing a reaction product of an oil-modified alkyd resin and an unsaturated oil having a conjugated double bond in the molecule as a main component. The method for producing a granular coated fertilizer is characterized in that the elution rate is controlled by changing the kind and film thickness of the wax or the compatible material of the wax and the ethylene-vinyl acetate copolymer resin.

The wax used in the present invention has a melting point of 60.
It is preferably in the range of to 120 ° C. With the granular fertilizer primarily coated with wax having a melting point of 60 ° C. or less, a problem occurs when the coating material of alkyd resin and unsaturated oil is secondarily coated. That is, when the coating temperature is 60 ° C. or lower, the curing reaction rate is very slow, the productivity is lowered, and the coating film peels off during coating. Further, when the coating temperature is higher than 60 ° C., the wax melts and the whole becomes a gum-like lump, and uniform secondary coating cannot be performed. On the other hand, when a wax having a melting point of 120 ° C. or higher is used, it is necessary to melt and spray the wax at a temperature of 120 ° C. or higher in the primary coating, which is not beneficial in terms of energy cost.

The compatible material of the wax and the ethylene-vinyl acetate copolymer resin used in the present invention is composed of a wax having a melting point of 60 ° C. or higher and an ethylene-vinyl acetate copolymer resin having a vinyl acetate content of 40% or less. The content of the ethylene-vinyl acetate copolymer resin in the melt is 30% or less.

The reason why the wax is used here is to impart water resistance, but the reason for mixing the compatible material with the ethylene-vinyl acetate copolymer resin is to improve the water resistance and wax coated on the granular fertilizer. Has the effect of raising the temperature at which the is melted to deteriorate the sticky flow state (hereinafter referred to as the blocking temperature). Since the blocking temperature is increased by about 5 to 20 ° C. by using the compatible material, the secondary coating temperature is increased,
The curing reaction can be promoted and the productivity can be improved.

As the amount of ethylene-vinyl acetate copolymer resin added increases, the blocking temperature also rises.
% Or less, no effect is obtained, and even if 30% or more is added, the blocking temperature does not change. On the other hand, if it is 30% or more, the viscosity of the compatible material increases, which causes a problem in handling.
Therefore, the addition amount is preferably 5 to 30% and optimally 5 to 20%. The addition amount varies depending on the melting point of the wax used, but is appropriately selected so that the blocking temperature is as high as possible. Further, the ethylene-vinyl acetate copolymer resin used is 40% or less of vinyl acetate, and if it is 40% or more, the compatibility with the wax is deteriorated, which is not preferable. Furthermore, the degree of polymerization of the ethylene-vinyl acetate copolymer resin is not particularly limited.

The wax used here is not particularly limited, and various synthetic waxes such as carbowax and hex wax, various natural waxes such as carnauba wax and beeswax, and thermoplastic resins having wax-like performance. Materials such as can be used. Further, additives such as rosin acid ester, rubber resin, ethylene / vinyl acetate copolymer resin, etc. may be added to the wax in order to improve adhesiveness, water resistance and the like.

The oil-modified alkyd resin used in the present invention is a polybasic acid such as phthalic anhydride or maleic anhydride, a polyhydric alcohol such as pentaerythritol or glycerin, and a natural vegetable oil or vegetable fat or natural oil as a modifier. A general one obtained by heat-condensing animal fat may be used, and the kind thereof is not particularly limited.

Examples of the natural vegetable oil or vegetable fat include soybean oil, linseed oil, tung oil, surfflower oil, coconut oil, palm oil, tall oil and the like. Examples of natural animal fats include beef tallow.

The molecular weight is preferably in the range of 500 to 5000. When the molecular weight is less than 500, the film formed by the reaction with the unsaturated oil is brittle and the curing and drying rate is slow. On the other hand, when the molecular weight is 5,000 or more, the viscosity becomes high and it becomes difficult to coat the fertilizer efficiently.

Examples of the unsaturated oil having a conjugated double bond in the molecule include tung oil, dehydrated castor oil and the like. Tung oil is mainly composed of eleosteric acid having a conjugated double bond. Dehydrated castor oil has 9,1 conjugated double bonds
High in 1-linoleic acid. These tung oil, dehydrated castor oil and the like can be used as they are or after purifying the target components.

These unsaturated oils have the effect of diluting the alkyd resin and lowering the viscosity, and themselves crosslink with the unsaturated oil or the alkyd resin in the presence of a metal soap to form a resin (solidify).

The mixing ratio of the above oil-modified alkyd resin and unsaturated oil is usually preferably in the range of 2: 8 to 7: 3 by weight. If the mixing ratio of the oil-modified alkyd resin is less than this range, the coating produced is brittle and the water resistance is poor. On the other hand, if the proportion of the alkyd resin is higher than this range, the viscosity will be too high and it will be difficult to coat it efficiently.

As the metal soaps, naphthenes such as manganese, cobalt, zirconium, nickel, iron and lead, or octyl acids can be usually used. For example, zirconium octylate, manganese naphthenate, cobalt octylate can be used alone or in a mixture thereof in an amount of 0.5 to 3 based on the total amount of the oil-modified alkyd resin and the unsaturated oil.
A weight% range is preferred. Below this, the reaction rate is not sufficient, and even if it exceeds this range, there is no point in adding it and it is not economical.

The effect of the wax in the present invention is as follows.
Since the glass transition temperature of the alkyd resin is low, the water resistance is poor at room temperature and above. Further, it is expected to improve performance such as poor film forming property due to large shrinkage during curing and poor water permeability. Further, the compatible material of the wax and the ethylene-vinyl acetate copolymer resin has the effect described above, and further increases the blocking temperature and enhances the productivity.

That is, the wax or the compatible material of the wax and the ethylene-vinyl acetate copolymer resin is primarily coated, so that the layer of the solidified reaction product of the alkyd resin and the unsaturated oil of the secondary coating is permeated. Prevents the infiltration of water molecules that have been carried out and further enhances water resistance.

The elution control method can be freely controlled depending on the film thickness and the kind of the wax or the compatible material of the wax and the ethylene-vinyl acetate copolymer resin. It can be controlled also by the film thickness of the reaction product layer of the alkyd resin and the unsaturated oil, but the water resistance is inferior as compared with the wax or the compatible material of the wax and the ethylene-vinyl acetate copolymer resin. Therefore, it is necessary to make a thick film, which is not economical.

Further, the reason why the wax layer or the compatible layer of the wax and the ethylene-vinyl acetate copolymer resin is the primary coating and the reaction product of the alkyd resin and the unsaturated oil is the secondary coating is because the wax or the wax is used. This is to solve the problem when the compatible material of ethylene and vinyl acetate copolymer resin is coated with the outer layer (secondary coating). That is, in the coated granular fertilizer having the alkyd resin, the unsaturated oil and the reaction product as the primary coating and the wax or the compatible material of the wax and the ethylene-vinyl acetate copolymer resin as the secondary coating, the wax or the wax and the ethylene-acetic acid are used. The compatibility with the vinyl copolymer resin has a problem that mechanical properties such as abrasion resistance and impact resistance and microbial decomposition are likely to occur, which adversely affects the elution performance. Furthermore, the wax melts during outdoor storage, impairs the elution performance, and may cause solidification, which is not preferable.

In the case of a coated granular fertilizer having a wax or a compatible coating of a wax and an ethylene-vinyl acetate copolymer resin and a secondary coating of a reaction product of an alkyd resin and an unsaturated oil, the alkyd resin and the unsaturated The reaction product with oil is superior in mechanical properties as compared with the wax or the compatible material of the wax and the ethylene-vinyl acetate copolymer resin, and is less likely to undergo microbial decomposition, and further, when the coated granular fertilizer is stored outdoors. Even if the wax melts, there is no fear of solidification if it is secondarily coated with the reaction product of the alkyd resin and unsaturated oil.

From the above, it is possible to form a coated granular fertilizer having a wax or a compatible coating of a wax and an ethylene-vinyl acetate copolymer resin as a primary coating, and a reaction product of an alkyd resin and an unsaturated oil as a secondary coating. In addition, it is possible to solve the problems in the physical properties of the wax and make the best use of the water resistance, which is an advantage.

On the other hand, the granular fertilizer is not particularly limited as long as it is granular. Ordinary fertilizers such as ammonium chloride, ammonium sulfate, urea,
It is possible to use potassium chloride or the like alone, or compound fertilizers such as NK chemical conversion, ammonium chloride phosphorus, potassium phosphate ammonium nitrate, and granular organic fertilizers.

The method for coating granular fertilizer in the present invention is as follows:
It can be carried out by a known method of bringing it into a fluid or rolling state. For example, it can be brought into a fluid state by a fluidizing device or a jet fluidizing device, and can be brought into a rolling state by a rotating pan, a rotating drum, or the like.

As a condition for the wax or the compatible coating of the wax and the ethylene-vinyl acetate copolymer resin (primary coating), there is no problem with the spraying temperature as long as the primary coating is molten.
It is not economical to make it higher than necessary. Depending on the physical properties of the wax, the coating temperature is usually 10 to 120 ° C., but the coating temperature is preferably lower than the melting point of the wax in order to avoid blocking.

The conditions for coating the alkyd resin with the unsaturated oil (secondary coating) are usually in the range of 60 to 120 ° C., but the wax or the wax which has been primary coated and the ethylene-vinyl acetate copolymer are used. The coating is performed at a temperature equal to or lower than the melting point of the compatible material with the resin. If the melting point is higher than the melting point, blocking occurs and uniform coating is not possible, and the oxidative polymerization reaction between the alkyd resin and unsaturated oil is difficult to proceed.

Further, the coating temperature must be relatively low in the case of granular fertilizer containing a component which is easily decomposed or deteriorated by heat. For example, in the case of urea, 9
It is preferably 0 ° C or lower.

As a method for adding the waxes and the solvent-free coating material, it can be carried out by spraying or dripping, as long as they can be dispersed and added efficiently. Solventless coatings are usually preferably added by spraying with a two-fluid nozzle using air. Further, since the solventless coating material generally has a high viscosity, it is desirable to add it after lowering the viscosity by heating.

[0037]

The present invention will be described in detail below with reference to examples of the present invention, but the present invention is not limited to these examples.

Example 1 A fluidized bed coating apparatus having a tower diameter of 10 cm had an average particle diameter of 3.3 mm.
800 g of urea was charged, and hot air was blown from the bottom at 60 m ³ / Hr to make it flow, and the temperature was maintained at 70 ° C.

On the other hand, a wax melted (90 ° C.) was sprayed from the upper portion using a two-fluid nozzle to obtain a coated granular fertilizer having a constant film thickness. Moreover, coated granular fertilizers having various film thicknesses were obtained by changing the spraying speed.

The obtained coated granular fertilizer was subjected to a nitrogen (N) dissolution test, and the results are shown in Table 1. To measure the dissolution rate, put the coated granular fertilizer in a certain amount of water, leave it in a constant temperature bath at 25 ° C, take it out after a certain period of time, separate the fertilizer and the solution, and quantify the nitrogen content eluted in the water. I asked.

The wax used was paraffin wax (a): melting point 75 ° C., penetration 6 (25 ° C.), viscosity 6.9.
cSt / 100 ° C., oil content 0.1% or less, (b): melting point 89
° C, penetration 5 (25 ° C), viscosity 15.2 cSt / 120
There are two types, ℃ and oil content 0.1% or less.

[0042]

[Table 1]

Example 2 The coated granular fertilizer prepared in Example 1 with the wax grade (a) was kept at 70 ° C. with hot air. On the other hand, 6 from the top
A coating material (60% soybean oil-modified alkyd resin 30%, tung oil, conjugated linoleic acid pentaerythritol ester 15%, metal soap 3%, anti-skinning agent 2%) heated to 0 ° C. at a flow rate of 0.5 g / min, Spraying was performed using a two-fluid nozzle to obtain a coated granular fertilizer having a constant film thickness. The obtained granular fertilizer was subjected to a nitrogen (N) dissolution test, and the results are shown in Table 2.

[0044]

[Table 2]

Example 3 The wax-coated granular fertilizers produced in A and D of Example 1 were treated in the same manner as in Example 2. The obtained granular fertilizer was subjected to a nitrogen (N) elution test, and the results are shown in Table 3.

[0046]

[Table 3]

Example 4 A fertilizer to be coated was treated with nitrogen-containing chemical C having an average particle size of 3.1 mm.
No. 20 (N: 20%, K ₂ O: 10%) was used, and the same procedure as in Example 1 was performed. The results are shown in Table 4.

[0048]

[Table 4]

Example 5 Each of the coated granular fertilizers produced according to the wax brand a of Example 4 was kept at 70 ° C. by hot air. On the other hand, 6 from the top
Spray the coating material (60% soybean oil modified alkyd resin 30%, tung oil, conjugated linoleic acid pentaerythritol ester 15%, metal soap 3%, anti-skinning agent 2%) heated at 0 ° C using a two-fluid nozzle. A coated granular fertilizer having a constant film thickness was obtained. The obtained coated granular fertilizer was subjected to a nitrogen (N) elution test, and the results are shown in Table 5.

[0050]

[Table 5]

Example 6 The wax-coated granular fertilizers produced in Examples 4A and 4D were treated in the same manner as in Example 2. The obtained coated granular fertilizer was subjected to a nitrogen (N) elution test, and the results are shown in Table 6.

[0052]

[Table 6]

Comparative Example 1 Urea 80 having an average particle size of 3.3 mm was placed in the same apparatus as in Example 1.
0 g was charged, hot air was blown from the bottom at 60 m ³ / Hr to flow, and the temperature was kept at 50 ° C.

On the other hand, wax melted from above (100 ° C.) (paraffin wax: melting point 53 ° C., penetration degree 17)
(25 ° C., viscosity 3.3 cSt / 100 ° C.) was sprayed using a two-fluid nozzle to obtain a coated granular fertilizer with a coverage of 5%.

Next, a coating material (60% soybean oil-modified alkyd resin 30%, tung oil, conjugated linoleic acid pentaerythritol ester 15%, metal soap 3%, anti-skinning agent 2%) was heated to 60 ° C. from above. It was atomized using a two-fluid nozzle. Coating material flow rate 0.5g / min, 0.3g /
As a result of carrying out at min and 0.05 g / min, 0.5
At neither g / min nor 0.3 g / min, the curing reaction did not proceed, but at 0.05 g / min, the hardening reaction proceeded and a coated granular fertilizer having a constant film thickness was obtained.

Comparative Example 2 A fertilizer to be coated was treated with nitrogen-containing chemical compound C having an average particle size of 3.1 mm.
No. 20 (N: 20%, K ₂ O: 10%) was used, and the same procedure as in Comparative Example 1 was performed. As a result, the flow rate is 0.5g
/ Min and 0.3 g / min, the curing reaction did not proceed, but at 0.05 g / min, the hardening reaction proceeded and a coated granular fertilizer with a constant film thickness was obtained.

Comparative Example 3 Wax coating was carried out in the same manner as in Comparative Example 1, and then hot air was blown to maintain the temperature at 70 ° C. The wax melted and the fertilizer stopped flowing at all, and the coating could not be carried out.

Example 7 200 g of urea having an average particle size of 3.3 mm was added to an outer diameter of 200φ ×
The mixture was placed in a 60 mm rotating pan, heated to about 60 ° C. with hot air, and 10 g of wax melted at 150 ° C. or a compatible material of the wax and the ethylene-vinyl acetate copolymer resin was sprayed and uniformly coated. Next, the hot air temperature was raised and the temperature at which melting and blocking occurred was measured. The results are shown in Table 7. Incidentally, M of Example 7 was not compatible.

[0059]

[Table 7]

Example 8 A fluidized bed coating apparatus having a tower diameter of 10 cm had an average particle diameter of 3.3 mm.
800 g of urea was charged, and hot air was blown from the bottom at 60 m ³ / Hr to make it flow, and the temperature was maintained at 70 ° C.

On the other hand, the melted (110 ° C.) compatible material of the wax and the ethylene-vinyl acetate copolymer resin was sprayed from above using a two-fluid nozzle to obtain a coated granular fertilizer having a constant film thickness. Moreover, coated granular fertilizers having various film thicknesses were obtained by changing the spraying speed.

The coated granular fertilizer thus obtained was subjected to a nitrogen (N) dissolution test. The results are shown in Table 8. To measure the dissolution rate, put the coated granular fertilizer in a certain amount of water, leave it in a constant temperature bath at 25 ° C, take it out after a certain period of time, separate the fertilizer and the solution, and quantify the nitrogen content eluted in the water. Ask.

There are the following four kinds of compatible materials of the wax and the ethylene-vinyl acetate copolymer resin used. Compatibilities (a) Paraffin wax 90%: melting point 75 ° C, penetration degree 7 (25 ° C), viscosity 6.9 cSt / 100 ° C (b) ethylene-vinyl acetate copolymer resin 10%: vinyl acetate content 19% , Vicat softening point 59 ° C., melt flow rate 1.5 g / min compatible material (a) Paraffin wax 90%: melting point 89 ° C., penetration 6 (25 ° C.), viscosity 8.2 cSt / 100 ° C. (b) ethylene -Vinyl acetate copolymer resin 10%: vinyl acetate content 19%, Vicat softening point 59 ° C, melt flow rate 1.5 g / min compatible material (a) paraffin wax 90%: melting point 75 ° C, penetration 7 ( 25 ° C.), viscosity 6.9 cSt / 100 ° C. (b) Ethylene-vinyl acetate copolymer resin 10%: vinyl acetate content 6%, Vicat softening point 87 ° C., melt flow rate 2.5 g / min phase (A) Paraffin wax 80%: melting point 75 ° C., penetration degree 7 (25 ° C.), viscosity 6.9 cSt / 100 ° C. (b) ethylene-vinyl acetate copolymer resin 20%: vinyl acetate content 19%, vicat Softening point 59 ° C, melt flow rate 2.5 g / min

[0064]

[Table 8]

Example 9 The coated granular fertilizer produced from the compatible material of Example 8 was kept at 80 ° C. with hot air. On the other hand, coating material (60% soybean oil modified alkyd resin 30%, tung oil, conjugated linoleic acid pentaerythritol ester 15
%, Metal soap 3%, anti-skin 2%) flow rate 0.5g
/ Min using a two-fluid nozzle to obtain a coated granular fertilizer having a constant film thickness. The obtained coated granular fertilizer was subjected to a nitrogen (N) elution test, and the results are shown in Table 9.

[0066]

[Table 9]

Example 10 The coated granular fertilizer prepared from the compatibilities of A, D, G and J of Example 8 was treated in the same manner as in Example 9. The obtained coated granular fertilizer was subjected to a nitrogen (N) elution test, and the results are shown in Table 10.

[0068]

[Table 10]

Example 11 The fertilizer to be coated was nitrogen-hydrogenated C having an average particle size of 3.1 mm.
No. 20 (N: 20%, K ₂ O: 10%) was used, and the same procedure as in Example 8 was carried out. The obtained coated granular fertilizer was subjected to a nitrogen (N) elution test, and the results are shown in Table 11.

[0070]

[Table 11]

Example 12 The coated granular fertilizer produced from the compatible material of Example 11 was kept at 80 ° C. with hot air. On the other hand, coating material (60% soybean oil modified alkyd resin 30%, tung oil, conjugated linoleic acid pentaerythritol ester 15
%, Metal soap 3%, anti-skinning agent 2%) was sprayed using a two-fluid nozzle to obtain a coated granular fertilizer having a constant film thickness. The obtained coated granular fertilizer was subjected to a nitrogen (N) elution test, and the results are shown in Table 12.

[0072]

[Table 12]

Example 13 The coated granular fertilizer prepared from the compatibilities of A, D, G and J of Example 10 was treated in the same manner as in Example 9. The obtained coated granular fertilizer was subjected to a nitrogen (N) dissolution test, and the results are shown in Table 13.
It was shown to.

[0074]

[Table 13]

Example 14 The same treatment as in Example 9 was carried out except that the hot air temperature was changed for the coated granular fertilizer prepared by using the compatible material of Example 8 in which the amount of the ethylene-vinyl acetate copolymer resin added was changed. . The results showed that the compatible material could be coated at a hot air temperature of 80 ° C., but at 85 ° C., the compatible material melted and stopped flowing. Further, the compatible material could be coated at a hot air temperature of 85 ° C., but at 90 ° C., the compatible material melted and did not flow.

Comparative Example 4 Urea 80 having an average particle size of 3.3 mm was placed in the same apparatus as in Example 7.
0 g was charged, and hot air was blown from the bottom at 60 m ³ / Hr to make it flow and was kept at 60 ° C.

On the other hand, wax melted (100 ° C.) from above (paraffin wax: melting point 75 ° C., penetration degree 7 (2
5 ° C., viscosity 6.9 cSt / 100 ° C.) was sprayed using a two-fluid nozzle to obtain a coated granular fertilizer with a coverage of 5%.

Next, a coating material (60% soybean oil-modified alkyd resin 30%, tung oil, conjugated linoleic acid pentaerythritol ester 15%, metal soap 3%, anti-skinning agent 2%) was heated from the top to 60 ° C. It was atomized using a two-fluid nozzle. Coating material flow rate 0.5g / min and 0.1g
As a result, the curing reaction did not proceed. Further, when the hot air temperature was set to 75 ° C., the wax was melted, causing blocking and not flowing, so that coating could not be performed.

Comparative Example 5 A fertilizer to be coated was treated with nitrogen-containing chemical C having an average particle size of 3.1 mm.
No. 20 (N: 20%, K ₂ O: 10%) was used, and the same procedure as in Comparative Example 4 was performed. As a result, it was similar to Comparative Example 4.

[0080]

Since the granular fertilizer coating composition of the present invention does not contain an organic solvent, it is not necessary to consider operational problems such as flammability and environmental pollution problems. Furthermore, when the present coating composition is used, the elution rate of the components of the granular fertilizer can be controlled very easily and reliably, and labor saving in agricultural work can be facilitated.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Yamamoto 5253 Oki Ube, Ube City, Yamaguchi Prefecture Central Rural Co., Ltd. Ube Laboratory

Claims (3)

[Claims] 1. The surface of the granular fertilizer has a melting point of 60 to 120 ° C.
It is characterized by being coated with a primary coating layer containing wax as a main component and a secondary coating layer containing a reaction product of an oil-modified alkyd resin and an unsaturated oil having a conjugated double bond in the molecule as a main component. Multi-layer coated granular fertilizer. 2. The surface of the granular fertilizer has a melting point of 60 to 120 ° C.
Of the wax and the ethylene-vinyl acetate copolymer resin as a main component of the primary coating layer, an oil-modified alkyd resin and a reaction product of an unsaturated oil having a conjugated double bond in the molecule as a main component A multi-layer coated granular fertilizer characterized by being coated with a secondary coating layer. 3. The elution rate is controlled by changing the kind and the film thickness of the wax or the compatible material of the wax and the ethylene-vinyl acetate copolymer resin. Method for producing multi-layer coated granular fertilizer of.