JPH06191980A - Composition for coating fertilizer, coated granular fertilizer and production thereof - Google Patents

Abstract

PURPOSE:To excellently coat a fertilizer without using an organic solvent causing pollutive problems to environment, etc., in relation to coating of a granular fertilizer for freely controlling dissolution of the fertilizer components. CONSTITUTION:The pattern of dissolution is controlled by using a coating material composed mainly of an oil-modified alkyd resin, an unsaturated oil having a conjugated double bond in the molecule, wax and petroleum resin and changing the kind and the ratio of wax and petroleum.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, various fertilization-controlling fertilizers have been developed and put on the market for the purpose of supplying nutrients according to the growth of crops.

Particularly in recent years, demand for labor-saving and highly efficient fertilizers has been increasing along with a decrease in the number of agricultural workers, a change in social structure such as aging, and an increase in environmental conservation agriculture. In order to cope with such a background, a so-called coated fertilizer in which the surface of a fast-acting fertilizer is coated with a coating material such as sulfur or resin so as to control the elution is dominated.

Examples of fertilization control methods and coating materials for these coated fertilizers include those using ethylene-vinyl acetate copolymer (Japanese Patent Publication No. Sho 60-21952), olefin resin and ethylene-vinyl acetate copolymer. Method of adjusting the fertilizing effect by adding a water-soluble surfactant to the coating material (Japanese Patent Publication No. 37074/60), and other secondary coating with wax containing sulfur as the main component,
A method of coating with various other resins and controlling the elution by the film thickness has been proposed.

Most of these coating materials are thermosetting or thermoplastic resins, and most of them are materials that remain in soil for many years. On the other hand, a material coated with an inorganic substance such as sulfur or sodium silicate has a thick film, and it is difficult to control fertilization at a high level.

That is, from the viewpoint of environmental protection, it is desirable that the membrane from which fertilizer has been completely dissolved is promptly decomposed, and a membrane capable of controlling fertilization effect is ideal. In addition, it is required that the elution pattern from the fertilizer, which takes into consideration the nutritional physiological aspects of the crop and the soil environment in which it grows, does not elute almost for a certain period after the fertilizer application.

Taking the case of paddy rice as an example, at the soil fertilizer fertility (high soil nitrogen content), the nutrient supply from the fertilizer at the early stage of growth is small, and conversely, the nutrient-absorption is active from the earing stage to the panicle stage. A large amount of nutrients will be needed during the cultivation.

Other crops are often required to have similar characteristics, and it is desirable that the fertilizer be capable of supplying an appropriate amount of nutrients in a timely manner, and that the coating material used should not be left in the soil.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that by using a biodegradable alkyd resin or the like as the coating material,
The present invention has been accomplished by finding a coating material capable of obtaining a coated granular fertilizer whose elution control is easy.

That is, the present invention is a fertilizer coating composition comprising an oil-modified alkyd resin, an unsaturated oil having a conjugated double bond in the molecule, a wax and a petroleum resin as main components,
The surface of the granular fertilizer is mainly coated with an oil-modified alkyd resin, a reaction product of an unsaturated oil having a conjugated double bond in the molecule, a mixture of a wax and a petroleum resin, and the outer layer thereof is an oil-modified alkyd resin. , Coated granular fertilizer characterized by being coated with a reaction product with an unsaturated oil having a conjugated double bond in the molecule, and further, the wax to be coated on the inner layer, the addition rate and type of petroleum resin are changed. This is a method for producing a coated granular fertilizer, which is characterized in that the elution pattern is controlled by controlling the concentration.

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 animal fat as a modifier. A general one obtained by heating and condensing
The type 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 and the like. Examples of natural animal fats include beef tallow.

The molecular weight is preferably in the range of 500 to 5,000. When the molecular weight is less than 500, it takes a long time to form the coating film because the coating film formed by the reaction with the unsaturated oil is brittle and the curing and drying speed is slow. On the other hand, when the molecular weight exceeds 5,000, the viscosity becomes high and it becomes difficult to form a coating film efficiently and uniformly.

Examples of the unsaturated oil having a conjugated double bond in the molecule include tung oil and dehydrated castor oil. Tung oil is mainly composed of eleostearic acid having a conjugated double bond. Dehydrated castor oil has a conjugated double bond9.
11 Contains a large amount of 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 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. When the ratio of the oil-modified alkyd resin is less than this range, the formed film 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 metal soaps, naphthenes such as manganese, cobalt, zirconium, nickel, iron, lead or octylic acids can be usually used. For example, zirconium octylate, manganese naphthenate, cobalt octylate may be used alone or in a mixture thereof in an amount of 0.5 to 3 of 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 the reaction rate exceeds this range, there is no point in adding, and it is not economical.

The waxes have a softening point of 40.
In the range of ℃ to 150 ℃, preferably a softening point of 70
A material in the range of ℃ to 110 ℃ is used. Softening point is 40 ° C
In the following cases, the wax may melt during outdoor storage and impair the elution performance, and may cause caking.
When the softening point is 150 ° C. or higher, heat shrinkage or the like at the time of forming the film inhibits uniform thickness, making it difficult to obtain a product having the desired elution performance.

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.

Next, examples of the petroleum resin include an aliphatic hydrocarbon resin whose main raw material is a C5 fraction and an aromatic hydrocarbon resin whose main component is a C9 fraction, but waxes are preferable. C9 series having high compatibility with is desirable. C9
The main components of petroleum resin are styrene, vinyltoluene, α-
It is a copolymer of methylstyrene and indene and has a softening point of 70 to 150 ° C, preferably 90 to 120 ° C.

As a primary coating material, a mixture of an alkyd resin and waxes is heat-melted and coated, and the addition rate of waxes in the primary coating layer is 2 to 30% by weight, preferably 5 to 2%.
0 wt% is desirable. If the amount is less than this range,
It is difficult to suppress the initial elution, and if it is more than this, wear of the film during coating occurs.

Therefore, the adhesion with the alkyd resin coating the outer layer is impaired. Further, the reason why the outermost layer is coated with the alkyd resin is that when a large amount of waxes is coated on the outermost layer, there is a concern that heat blocking may occur during outdoor storage.

Fertilizers to be coated in the present invention include simple fertilizers such as ammonium chloride, urea and potassium chloride, which are usually used, compound fertilizers such as NK chemical, ammonium chloride and phosphorus nitrate, and granular organic fertilizers. It is not particularly limited.

Further, the coating method can be carried out by any of commonly used fluidized bed, rotary drum type and pan type coating devices. The coating temperature is 60 to 150 ° C., and in the case of urea which may decompose under heat, a slightly lower temperature of 90 ° C. or lower is desirable.

[0025]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples.

Example 1 A fluidized bed coating apparatus having a tower diameter of 10 cm and an average particle diameter of 3.3 mm was used.
800 g of urea was charged, and hot air was blown from the bottom at 60 m ³ / Hr to make it flow and held at 85 ° C.

On the other hand, the primary coating material (60% soybean oil-modified alkyd resin 30%, tung oil 50) heated to 60 ° C. from above
%, Conjugated linoleic acid pentaerythritol ester 15
%, Metallic soap 3%, anti-skinning agent 2%, and wax mixture) were sprayed using a two-fluid nozzle to form a primary film. Further, a secondary coating material (60% soybean oil-modified alkyd resin 30%, tung oil 50%, conjugated linoleic acid pentaerythritol ester 15%, metallic soap 3%, anti-skinning agent 2%) is sprayed by the same method, A coated granular fertilizer with a constant film thickness was obtained.

The coated granular fertilizer thus obtained was subjected to a nitrogen (N) elution test. The results are shown in Table 1 and FIG. To measure this dissolution rate, put the coated granular fertilizer into a certain amount of water,
It is left in a constant temperature bath at 25 ° C., taken out after a certain period of time, the fertilizer and the solution are separated, and the nitrogen content eluted in water is quantitatively determined.

[0029]

[Table 1]

Example 2 A coated granular fertilizer was obtained in the same manner as in C of Example 1 except that the kind of wax used in the primary coating material was changed.

The coated granular fertilizer thus obtained was subjected to a nitrogen (N) dissolution test. The results are shown in Table 2 and FIG.

[0032]

[Table 2]

Example 3 A coated granular fertilizer was obtained in the same manner as in Example 1C except that the wax used for the primary coating material was changed to a mixture of wax and petroleum resin.

The coated granular fertilizer thus obtained was subjected to a nitrogen (N) dissolution test. The results are shown in Table 3 and FIG.

[0035]

[Table 3]

Example 4 The fertilizer to be coated was nitrogen-containing chemical conversion C2 having an average particle size of 3.1 mm.
No. 0 (N; 20%, K2 O; 10%) was used, and the coating temperature was changed to 105 ° C. All the same results as in Example 1C were obtained. The results are shown in Table 4 and FIG. It was

[0037]

[Table 4]

[0038]

EFFECTS OF THE INVENTION According to the present invention, since it has biodegradability and can be coated without making the film thickness extremely thick, elution and fertilization can be easily and surely controlled, and labor saving in agricultural work is achieved. Will be easier.

[Brief description of drawings]

FIG. 1 shows the relationship between the number of days elapsed and the cumulative dissolution rate depending on the coating amount in Example 1.

FIG. 2 shows the relationship between the number of days elapsed and the cumulative dissolution rate depending on the coating amount in Example 2.

FIG. 3 shows the relationship between the number of days elapsed and the cumulative dissolution rate depending on the coating amount in Example 3.

FIG. 4 shows the relationship between the number of days elapsed and the cumulative dissolution rate depending on the coating amount in Example 4.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masayuki Tsubouchi 5253 Oki Obe, Ube City, Yamaguchi Prefecture Central Glass Co., Ltd. Ube Laboratory

Claims (3)

[Claims] 1. A fertilizer coating composition comprising an oil-modified alkyd resin, an unsaturated oil having a conjugated double bond in the molecule, wax and a petroleum resin as main components. 2. The surface of the granular fertilizer is mainly coated with a mixture of an oil-modified alkyd resin, a reaction product of an unsaturated oil having a conjugated double bond in the molecule, a wax and a petroleum resin, and an outer layer thereof. A coated granular fertilizer, which is coated with a reaction product of an oil-modified alkyd resin and an unsaturated oil having a conjugated double bond in the molecule. 3. A method for producing a coated granular fertilizer characterized in that the elution pattern is controlled by changing the addition rate and type of wax or petroleum resin with which the inner layer is coated.