JPH0674198B2 - Anti-floating coated granular fertilizer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improved coated granular fertilizer, which prevents the granular fertilizer from floating on the water surface when treated in a paddy field and the like. It is about.

[Prior Art and Problems] Conventionally, as a technology related to a coated granular fertilizer which prevents floating, for example, Japanese Patent Publication No. 60-20359 and Japanese Patent Publication No. 63-23160.
The inventions described in Japanese Patent Publications and the like are known.

These inventions relate to a coated granular fertilizer in which a fine powder and a surfactant are attached to a coated granular fertilizer whose outermost layer is coated with a coating material containing a resin. This technique gives hydrophilicity to the coated granular fertilizer by paying attention to the hydrophilicity of the surfactant. Here, it is thought that the role of the fine powder is to hold the surfactant stably on the fertilizer surface, and to impart hydrophilicity to the fertilizer granules in cooperation with the surfactant to prevent the floating property. Has been.

However, these inventions have various other problems because they use a surfactant. For example, since the surfactant has extremely strong hydrophilicity, it absorbs vapor or moisture in the atmosphere to facilitate elution of the fertilizer component in the coated granular fertilizer. Also, with a highly hydrophobic surfactant, it penetrates into the coating film,
It deteriorates the initial dissolution rate of fertilizer components in coated granular fertilizer.
In addition, the use of surfactants increases the manufacturing cost, making it a fertilizer that is more difficult to use by farmers who cannot invest much in material costs. Therefore, there is a strong demand for the appearance of a coated granular fertilizer which does not contain a surfactant and is prevented from floating.

[Means for Solving the Problems] As a result of various studies on the coated granular fertilizer which is prevented from floating, the present inventors have found a novel coated granular fertilizer which does not contain any surfactant, and completed the present invention. did.

That is, the present invention is an anti-floating method in which hydrous fine powder silicon oxide or fine hydrous silicon oxide and viscous mineral are adhered to the outermost surface of a granular fertilizer coated with a low molecular weight hydrophobic coating material. The present invention relates to coated granular fertilizers.

In the present invention, the coating film substance containing a low-molecular weight hydrophobic component means, for example, paraffin wax or olefin wax, and the low-molecular weight hydrophobic component means the oil content contained in these coating film substances. It means something good. Even in coating materials other than these paraffin wax and olefin wax, the technique of the present invention can be applied to a coated granular fertilizer containing a low-molecular weight hydrophobic component and the hydrophobic component exuding on the surface by perspiration action. It can be applied.

Originally, the specific gravity of coated granular fertilizer is greater than 1.00 and does not float when completely immersed in water. However, when water is gradually poured into the coated granular fertilizer, the surface is covered with a hydrophobic substance, so that it floats on the water surface due to surface tension. As a conventional floating prevention technique, a technique of adhering a surfactant and a fine powder to this coated surface is known, but this is only due to the synergistic effect of the surfactant and the fine powder to make the coated granular fertilizer hydrophilic. It is said to be given and the effect of each is extremely low. In the present invention, by using hydrous fine powder silicon oxide as the fine powder, a novel method for preventing floating is established by using only fine powder without using a surfactant.

Water-containing fine powder silicon is generally called white carbon, and is water-containing amorphous silicon dioxide synthesized by a wet method. The water-containing fine powder silicon oxide is composed of spherical fine particles each having a single particle size of about 10 to 30 mμ that are aggregated in a secondary and tertiary form in a grape shape to form one particle, which has a large specific surface area, a large pore volume, and oil absorption,
It is a fine powder with extremely high hydrophilicity.

When the fine powder is attached to the surface of the coated granular fertilizer, the specific surface area is increased and the contact angle with water is reduced, so that the surface is easily wetted. That is, when fine powder having a large hydrophilicity is used, the effect of temporarily preventing the floating is recognized only by the treatment of attaching the fine powder to the surface. However, with the passage of time, the low-molecular weight hydrophobic components present in the coating substance move to the surface and move to the surface of the fine powder as if covered by the hydrophobic coating, so that the hydrophilic effect of the fine powder disappears and the surface floats. Prevention cannot be achieved.

In the present invention, by using hydrous fine powder silicon oxide as the fine powder, the migration of the low-molecular weight hydrophobic component present in the coating substance is not sweated to the outermost surface of the fine powder, and the anti-floating property is maintained for a long time. Established a technology that can.

The amount of the water-containing fine powder silicon oxide used is controlled by the composition of the coating material and the specific gravity of the granular fertilizer to be coated, but is usually 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the granular fertilizer,
It is preferably 0.5 to 1.0 part by weight.

Further, the clay mineral in the present invention means sieglite, kaolin, zeolite, etc., and is one in which silicon oxide and aluminum oxide are brought together as a composition.
The amount of clay mineral used is preferably 5.0 parts by weight or less, and more preferably 0.5 to 1.0 part by weight, based on 100 parts by weight of the granular fertilizer.

The role of the clay mineral in the present invention is to adhere to the surface of the coated fertilizer together with the water-containing fine powder silicon oxide to facilitate the wetting of the fertilizer surface, but mainly to facilitate the adhesion of the water-containing fine powder silicon oxide to the surface of the coated fertilizer. It is in. That is, depending on the composition of the outermost layer, it is not easy to deposit the hydrous fine powder silicon oxide in the above proportion. For example, when the outermost layer is coated with a mixed layer of paraffin wax and diatomaceous earth, the coated granular fertilizer is placed in a rolling state, a fluidized state or a jet fluidized state at normal temperature, and water-containing fine powder silicon oxide is added. The fine particles of hydrous silicon oxide that easily adhere when applied are about 05 parts by weight with respect to 100 parts by weight of the granular fertilizer.
In order to make it adhere to about the weight part, it is necessary to intensify the movement of the coated granular fertilizer to increase the collision strength with the hydrous fine powder silicon oxide. When the clay mineral is put into a coated granular fertilizer placed in a rolling state, a fluidized state or a jet flow state together with water-containing fine powder silicon oxide, the water-containing fine powder silicon oxide easily adheres to the surface of the coating film.

This phenomenon is because the clay mineral is sandwiched between the particles of the hydrous fine powder silicon oxide and between the coating film and the hydrous fine powder silicon oxide, which facilitates physical adhesion, and the electric value charged by friction is oxidized. It can be inferred that silicon is negative, but the aluminum oxide portion contained in the clay mineral is positively charged, so that it is easily adsorbed electrically.

As described above, the present invention provides, firstly, a novel method for preventing ascending that does not use a surfactant by adhering hydrous fine powder silicon oxide on the surface of a coated granular fertilizer, and second, a fine hydrous powder. It is an object of the present invention to provide an adhesion treatment method for attaining the purpose of preventing floating of the hydrous fine powder silicon oxide by treating silicon oxide with a clay mineral.

Reference Example 1 A coated granular fertilizer having granular urea as a fertilizer nucleus, an inner layer of about 70 μm of a sulfur coating film as an outer layer and a mixed layer of paraffin wax and diatomaceous earth was prepared.

This production is based on the Tennessee River Basin Development Corporation.
Authority developed method (US Patent 3,877,41
5 gazette, 3,903,333 gazette, 3,991,225 gazette), based on the granular urea is rolled in the rotary drum for sulfur coating, so that the urea granules fall in the drum in a waterfall shape by the rectifying plate, the molten sulfur Spray it in a mist and apply sulfur to the surface.
It was coated to a thickness of 70 μm. Sulfur was coated at a ratio of 14.5 parts by weight with respect to 100 parts by weight of granular urea. Next, the paraffin wax melted on the rotary drum for sealant was mixed with 100 parts by weight of urea coated with sulfur as in the case of sulfur coating.
2.6 parts by weight was coated. Further, 2.5 parts by weight of diatomaceous earth was adhered to the surface with respect to 100 parts by weight of the coated urea with a drum for a conditioner. When roughly classified as described above, sulfur-coated urea was produced in three types of processes, but structurally, as a coated granular fertilizer, granular urea was used as a fertilizer core and about 70% as an inner layer.
A mixed layer of paraffin wax and diatomaceous earth was used with the μm sulfur coating film as the outer layer.

Example 1 1 g of the coated granular fertilizer of Reference Example 1 to which 10 g (1% by weight) of hydrous fine powder silicon oxide was added was uniformly adhered to the surface of the coating film in a rolling state to give a fine powder of hydrous silicon oxide. A coated granular fertilizer having an anti-floating property attached to the surface was produced.

Comparative Example 1 Hydrophilically treated coated granular fertilizer in which SiO ₂ dust and a surfactant are adhered to a coated granular fertilizer whose outermost layer is coated with a coating material containing a resin as shown in Japanese Examined Patent Publication No. 63-23160 as a comparative example. Was manufactured. That is, the coated granular fertilizer of Reference Example 1
10 g of SiO ₂ dust consisting mainly of anhydrous SiO ₂ per 1 kg
(1% by weight) to which 0.2 g (0.02% by weight) of a surfactant was added was uniformly attached to the surface of the coating film in a rolling state. As the surfactant, polyoxyethylene cyalkyl allyl ether, polyoxyethylene alkyl allyl ether sulfate (NH ₄ ) and alkyl allyl sulfonate (Na) were used.

Test Example 1 In this test, the hydrous fine powder silicon oxide treatment according to the present invention shows the effect of maintaining the elution control ability and preventing floating, and as a comparative example, a fertilizer produced when the surface of the coated granular fertilizer is treated with a surfactant. The changes in the elution properties of the components are shown below.

As the coated granular fertilizer, the coated granular fertilizer prepared in Example 1 in which hydrous fine powder silicon oxide was attached to the outermost layer was used. As a comparative example, the coated granular fertilizer prepared in Comparative Example 1 was subjected to hydrophilic treatment coated granular fertilizer in which SiO ₂ dust and a surfactant were adhered.

The floatation rate is the number of floating fertilizer grains in the number of fertilizer grains tested, and is shown as a percentage. The measurement method was to randomly sample about 400 grains of each test fertilizer produced in Example 1 and Comparative Example 1
Put in the beaker. After spreading the fertilizer particles so that they do not overlap more than twice, gently add 100 ml of water along the wall of the beaker.
Pour with a wash bottle. After standing for 30 seconds, the number of floating fertilizer particles was counted to obtain the floating rate. The initial dissolution rate is the ratio of the amount of components dissolved in 30 ° C water within 24 hours to the total amount of each component contained in the coated granular fertilizer, and was measured based on the fertilizer analysis method of National Institute for Agro-Environmental Sciences, Ministry of Agriculture, Forestry and Fisheries. . That is, 12.5 g of a sample was accurately placed in a 300 ml Erlenmeyer flask, 250 ml of water at 30 ° C. was accurately added, and the container was tightly sealed. The sample was left standing in a thermostat at 30 ° C. for 24 hours and then filtered with a dry filter paper. Accurately take a certain amount of the filtrate to quantify the fertilizer component in the solution,
The amount of initial eluted components was determined.

As a stability test of the coated granular fertilizer that was prevented from floating, each sample was put in a polyethylene bag and stored in a constant temperature bath at 30 ° C., taken out at 1 week, 2 weeks and 4 weeks, and the same floating test was conducted. An initial dissolution test was performed. Table 1 shows the results of the levitation test of this example and comparative examples. In the case where the surface of the coated granular fertilizer was treated with water-containing fine powder silicon oxide, no particles were observed that floated by water injection, and the effect did not change even after storage for 4 weeks. On the other hand, the one treated with the mixture of anhydrous SiO ₂ dust and the surfactant shows the anti-floating effect by the addition of the surfactant, but its degree is low, and the floatation rate is increased with the lapse of storage time. A rise was observed, and deterioration of the floating prevention effect was observed. Table 2 shows the results of the initial dissolution test. The initial elution rate of the treated granular fertilizer surface with hydrous fine powder silicon oxide was about 20%, which was similar to that of the untreated surface.
On the other hand, the one treated with the mixture of anhydrous SiO ₂ dust and the surfactant had an initial elution rate increased by the addition of the surfactant as compared with the one not treated with the surface, and the elution occurred with the lapse of storage time. A clear increase in the rate was observed. In this test, an attempt was made to prevent floating on the surface of coated granular fertilizer whose coating film consisted of sulfur, paraffin wax and diatomaceous earth, but the same applies to coated granular fertilizer using a mixed wax of polyethylene wax and paraffin wax as the coating material. Results were obtained.

Example 2 A test coated granular fertilizer prepared by adhering 10, 5, 2.5, or 1 g of hydrous fine powder silicon oxide to 1 kg of the coated granular fertilizer produced in Reference Example 1 and varying the amount of hydrous fine powder silicon oxide was used. Manufactured.

Test Example 2 In Test Example 1, the coating film was sulfur, paraffin wax,
The results of examining the anti-floating effect by attaching water-containing fine powder silicon oxide to the surface of coated granular fertilizer made of diatomaceous earth at a ratio of 1 part by weight to 100 parts by weight of coated granular fertilizer were shown.
In this test example, the floating prevention effect was investigated by changing the amount of the hydrous fine powder silicon oxide to be attached. The change in floating of the treated coated granular fertilizer with time was examined by the method shown in Test Example 1 after the treated product was placed in a constant temperature bath at 30 ° C and 45 ° C.
The test results are shown in Table 3. When the treatment amount of the water-containing fine powder silicon oxide was 0% and 0.1%, the anti-floating effect was not recognized, and all fertilizer grains floated.

When the treatment amount of the hydrated finely divided silicon oxide was 0.25%, 70% of the particles settled immediately after the treatment, and the effect of suppressing the floating was confirmed, if not sufficiently. However, the levitation rate is 45 at storage temperature of 30 ℃
Both the temperature increased with time, and 60% of the fertilizer particles at 30 ° C and 100% of the fertilizer particles at 45 ° C emerged at the 4th week of storage. This is because the addition amount of hydrous fine powder silicon oxide attached to the coated fertilizer
0.25% is not enough, it is difficult to uniformly adhere to all fertilizer surfaces, and even if adhered, the low molecular weight hydrophobic components eluting from the coating film exude to the surface and the fertilizer surface is It is considered to be in a state where it was covered with a hydrophobic film. The higher levitation rate at 45 ° C between the storage temperatures of 30 ° C and 45 ° C is presumed to be due to the faster perspiration of this low-molecular weight hydrophobic component.

When 0.5% or more of hydrous fine powder silicon oxide was applied to the coated granular fertilizer, no particles floated up to the 4th week at a storage temperature of 30 ° C, and even at 45 ° C, about 5% floated after the 2nd week. However, the levitation property is clearly suppressed,
It was practically usable.

Example 3 10 kg or 20 g of hydrous fine powder silicon oxide was added to 1 kg of the coated granular fertilizer produced in Reference Example 1 and adhered to the fertilizer surface, and hydrous fine powder silicon oxide and clay mineral were prepared.
A test coated granular fertilizer having 10 g added thereto and attached to the surface was produced. Adhesion is the diameter so that there is no difference in the adhesion process of each fine powder.
The rotation speed of a 1 m disk granulation tester was kept at 12 rpm and the time was kept constant for 2 minutes, and the particles were adhered in a fluidized state. Sieglite and kaolin were used as clay minerals.

Test Example 3 Each test granular fertilizer produced in Example 3 was burned in an electric furnace and the amount of ignition residue was measured. At the same time, the amount of the ignition residue of the coated granular fertilizer, hydrous fine powder silicon oxide and clay mineral produced in Reference Example 1 was measured, and the fine powder was attached to the surface of the coated granular fertilizer attached to the surface produced in Example 3. The amount of fine powder present was calculated. Table 4 shows the adhesion amount of the treated fine powder. When the hydrous fine powder silicon oxide alone is treated, 0.748% and 2 are added when 1% is added to the coated granular fertilizer produced in Reference Example 1.
%, 1.387% adhered to the surface, but when treated with 1% of water-containing fine powder silicon oxide and 1% of silicalite,
1.790%, 1.839% of fine powder adhered to the surface when treated with 1% of hydrous fine powder silicon oxide and kaolin, and by treating with water simultaneously with clay minerals compared with the case of hydrous fine powder silicon oxide alone treatment Clearly a lot of fine powder adhered.

Claims (6)

[Claims] 1. An anti-floating coated granular fertilizer comprising hydrous fine powder silicon oxide deposited on the outermost surface of a granular fertilizer coated with a coating film substance containing a low molecular weight hydrophobic component. 2. An anti-floating coated granular fertilizer, which is obtained by adhering hydrous fine powder silicon oxide and viscous mineral on the outermost surface of a granular fertilizer coated with a coating film substance containing a low molecular weight hydrophobic component. 3. The coated granular fertilizer according to claim 1, wherein the coating film substance is paraffin wax or olefin wax. 4. The coated granular fertilizer according to claim 2, wherein the hydrous fine powder silicon oxide is 0.1 to 5.0 parts by weight and the viscous mineral is 5.0 parts by weight or less with respect to 100 parts by weight of the granular fertilizer. 5. A method for preventing levitation by depositing hydrous fine powder silicon oxide on the outermost surface of a granular fertilizer coated with a coating film substance containing a low molecular weight hydrophobic component. 6. A method for preventing levitation by adhering hydrous fine powder silicon oxide and viscous minerals on the outermost surface of a granular fertilizer coated with a coating film substance containing a low molecular weight hydrophobic component.