JPH03146492A - Coated granular fertilizer with degradable coating film - Google Patents

Abstract

PURPOSE:To make it possible to regulate the duration of the effect of a granular fertilizer by coating the surface of the fertilizer with a mixture of polycaprolactone with an olefin polymer, a vinylidene chloride polymer, etc. CONSTITUTION:The surface of a granular fertilizer is coated with a mixture of polycaprolactone with one or more kinds selected among an olefin polymer, an olefin-contg. copolymer, a vinylidene chloride polymer, a vinylidene chloride- contg. copolymer, a diene polymer, waxes, petroleum resin, natural resin, fats and oils and modified products of them to form a degradable coating film on the fertilizer. The duration of the effect of the resulting coated granular fertilizer can be regulated and the coating film is degraded by microorganisms in soil.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coated granular fertilizer coated with a degradable coating. More specifically, the present invention relates to a coated granular fertilizer coated with a degradable film containing polycaprolactone as an essential component.

The film of the coated granular fertilizer of the present invention is decomposed by soil microorganisms and does not ultimately remain in the soil. In addition, in the coating,
Various auxiliaries or agents can be added to adjust the leaching of the coated granular fertilizer.

[Conventional technology]

Conventionally, various fertilizers with adjustable fertilizer effects have been developed for the purpose of expressing fertilizer effects according to the growth of crops, and in particular, many coated granular fertilizers in which the surface of the granular fertilizer is covered with a coating material have been disclosed. It is commercially available. For example, U.S. Patent No. 3,295,950
specification, Japanese Patent Publication No. 40-28927, Japanese Patent Publication No. 44
-28457 Publication, British Patent No. 815829, Japanese Patent Publication No. 37-15832, Japanese Patent Publication No. 1977-136
Although various materials have been proposed in Publication No. 81 and the like, it has been shown that it is difficult to control the elution rate of fertilizer components in all of them.

In contrast, in Japanese Patent Publication No. 60-21952 and Japanese Patent Publication No. 60-3040, when covering granular fertilizer with a coating material mainly composed of polyolefin, a solution of the coating material is sprayed onto the granular fertilizer and at the same time hot air flow is applied. A method of coating by drying with water is shown, and the feature of this technology is that the elution rate can be adjusted, and it has been put into practical use.

Furthermore, Japanese Patent Publication No. 60-3040 and Japanese Unexamined Patent Publication No. 55-1989
Publication No. 1672 discloses that by dispersing inorganic powder such as talc and sulfur into a film of polyolefin resin, etc., the elution control function is maintained, and at the same time, the collapse and decomposition of the film remaining after elution is promoted. It is shown.

[Problem to be solved by the invention]

In degradable films, degradability refers to decomposition by light, oxygen, and microorganisms, and in coated granular fertilizers, the film remains in the soil for a long time without being decomposed after the fertilizer components are eluted, and the elution rate is adjusted. It has been pointed out that this is difficult. In the coated granular fertilizers that have been proposed in the past, the coating does not disintegrate or decompose, and even if it disintegrates, it does not decompose and remains in the soil, which is useful for crop growth, soil environment, water supply around fields, rivers, etc. There is a risk of causing pollution. In addition, it is difficult to control the elution rate of fertilizer components in coated granular fertilizers coated with degradable films that have been proposed so far.
The effective period of fertilizer is easily affected by the environment such as weather and soil. A coated granular fertilizer with a degradable coating and an adjustable fertilization period is desired.

[Means to solve the problem]

The present inventors have studied the selection of a coating material in order to produce a granular fertilizer coated with a degradable coating whose coating is degradable and whose fertilization period can be adjusted, and have arrived at the present invention. It is something.

That is, the present invention applies polycaprolactone as a coating material A, and an olefin polymer, a copolymer containing an olefin, a vinylidene chloride polymer, a copolymer containing vinylidene chloride, or a diene-based coating material to the surface of a granular fertilizer as a coating material A. polymer,
This is a coated granular fertilizer consisting of a degradable film coated with a mixture of one or more substances selected from waxes, petroleum resins, natural resins, oils and fats, and modified products thereof.

The coated granular fertilizer of the present invention is obtained by spraying a solution made of the coating material onto the granular fertilizer and at the same time applying a high-speed hot air stream to that position to instantly dry and coat the fertilizer, and the coating is degradable. It is a coated granular fertilizer with adjustable fertilization period.

In the present invention, if necessary, as a third coating material component, for example, an elution regulator, a filler, etc. can be uniformly dispersed and used.

The coating material A in the present invention is polycaprolactone,
Coating material B is selected from olefin polymers, copolymers containing olefins, vinylidene chloride polymers, copolymers containing vinylidene chloride, diene polymers, waxes, petroleum resins, natural resins, oils and fats, and modified products thereof. type 1 or 2
It is a substance that is more than a species. Olefin polymers include polyethylene, polypropylene, ethylene/propylene copolymer, polybutene, butene/ethylene copolymer, butene/propylene copolymer, polystyrene, etc. Copolymers containing olefins include ethylene/acetic acid. vinyl copolymer,
Ethylene/acrylic acid copolymer, ethylene/acrylic acid ester copolymer, ethylene/methacrylic acid copolymer, ethylene/methacrylic acid ester copolymer, ethylene/carbon oxide copolymer, ethylene/vinyl acetate/ - a carbon oxide copolymer, etc., and the copolymer containing vinylidene chloride is a vinylidene chloride/vinyl chloride copolymer,
Diene polymers include butadiene polymers, isoprene polymers, chloroprene polymers, butadiene/styrene copolymers, EPDM polymers, styrene/isoprene copolymers, etc. Waxes include beeswax, wood wax, etc. , paraffin, etc., natural resins include natural rubber, rosin, etc., and oils and fats and modified products thereof include hydrogenated oils, solid fatty acids, metal salts, etc.

The weight percentage of the coating material of the present invention relative to the coated granules, that is, the coverage rate, is preferably in the range of 2 to 20%.

Further, coating material A occupies 10 to 90% (weight) of the entire coating material, and coating B is used in a range of 10 to 90% (weight) of the entire coating material. Note that as the third coating material component that can be mixed as necessary, a surfactant as an elution regulator, talc as an insoluble filler, calcium carbonate, metal oxide, etc. can be used. These mixtures need to be uniformly dispersed; if they are non-uniform, some of the fine particles will be biased and the continuous phase of the coating material will be impaired and the effectiveness of the coating will be lost.

In the present invention, a solution in which the coating material is dissolved or dispersed in a solvent such as chlorinated hydrocarbons is kept at high temperature, and is added to granular fertilizer in the form of a spray, and at the same time, a high-speed hot air stream is applied to that location to instantly dry it. A coated granular fertilizer can be obtained by coating the fertilizer.

〔Example〕

The present invention will be explained below with reference to Examples.

Examples 1 to 9 and Comparative Example (1) Apparatus and manufacturing method Figure 1 shows a preferred example of the apparatus, where 1 is a jet column and the column diameter is 2.
00 mm, height 1800 mm, air jet diameter 42 mm, and has 2 fertilizer input ports and 3 exhaust gas jet ports. The jet air is sent from the blower IO and reaches the jet tower via the orifice flow meter 9 and the heat exchanger 8, but the flow rate is controlled by the flow meter and the temperature is controlled by the heat exchanger, and the exhaust gas is sent from the exhaust gas outlet 3 to the outside of the tower. guided by. The granular fertilizer to be subjected to coating treatment is placed in fertilizer input port 2.
A jet is formed by blowing hot air through a specified amount of hot air. Coating treatment begins after the coated particle temperature reaches a predetermined temperature.
The polycaprolactone-containing coating liquid is sprayed in a spray form toward the jet stream through the liquid nozzle 4. The coating solution is prepared by putting a predetermined amount of coating material and a solvent into a liquid tank 11, and stirring the solution near the boiling point of the solvent. The supply of coating liquid is sent to the nozzle 4 by a pump 5, and this system is sufficiently insulated to maintain the temperature.

Once the prescribed coating liquid has been supplied, the pump is stopped and then the blower is stopped. The coated fertilizer is removed from the extraction lower. 6 is a valve.

In FIG. 1, T,, T2. 'ra, is a thermometer, and SL is steam. In addition, in this example, coating with granular fertilizer was performed while maintaining the following basic conditions.

Liquid nozzle; opening 0.8 mm, full-contact type hot air flow rate; 4 blows/min; hot air temperature; 100°C; type of fertilizer; 5-7 mesh phosphorus sulfate and alkali fertilizer input amount; 5 kg; coating liquid concentration; solid content 5% by weight; coating liquid Supply amount: 0.5 kg/min Coating time: 1
0 minute coverage (relative to fertilizer), 5.5% by weight (however, surfactant content is added) Solvent; composition of tetrachlorethylene (2) film and its nitrogen elution amount Coated phosphorus nitrate Azakari coatings having various film compositions shown in the following were manufactured, and the nitrogen elution amount of each was tested. The results are listed in Table 1.

(3) Soil decomposition test for film The 30 samples of this example were cut on two sides one by one, and left to stand in water to remove the fertilizer inside to form a ring-shaped film.

The soil is 9 mcs (2 ml) of fertile diluvial soil (Fuji City).
The soil that passes through a sieve is used as the test soil. The test soil is placed in a box to make a bed, and the ring is buried horizontally in the bed to a depth of about 1 to 2.5 cm, and the box is placed in a greenhouse. Pour water occasionally to prevent the bed from drying out. This is dug out every three months to observe the condition of the ring and measure its strength. These observation conditions are shown in Table 2, and the intensities of Comparative Examples and Examples 1 to 3 are shown in FIG.

Moreover, the strength retention rates of Comparative Examples and Examples 1 to 3 are shown in FIG.

U.S. bottom margin) Table 2 [Effects of the invention] The coated granular fertilizer of the present invention can adjust the duration of fertilizer effect,
After the fertilizer content is leached out, the coating is disintegrated and decomposed by soil microorganisms and does not remain in the soil. Furthermore, the amount of remaining components after the cultivation period of crops disappears due to the collapse and decomposition of the coating, which has the effect of facilitating fertilizer management.

[Brief explanation of the drawing]

Figure 1 is a front view showing an example of an apparatus suitable for manufacturing the product of the present invention, Figure 2 is a graph showing the change in strength of a ring-shaped coating in a soil decomposition test, and Figure 3 is a ring-shaped coating before a soil decomposition test. It is a graph showing the change in strength retention when the strength of 100%.

Claims (1)

[Claims] 1. Polycaprolactone as coating material A on the surface of granular fertilizer, and olefin polymer, copolymer containing olefin, vinylidene chloride polymer, copolymer containing vinylidene chloride, diene polymer, waxes as coating material B A coated granular fertilizer characterized by being coated with a mixture of one or more substances selected from petroleum resins, natural resins, oils and fats, and modified products thereof.