JPS6323160B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coated granular fertilizer that has been subjected to hydrophilic treatment and a hydrophilic treatment method thereof. More specifically, the present invention includes:
This article relates to a hydrophilic coated granular fertilizer obtained by treating a water-repellent granular fertilizer coated with a resin with SiO ₂ dust and a surfactant, and a method for treating the same. A coated fertilizer has been developed in which granular fertilizer is coated with a water-resistant film to control the solubility of fertilizer components. This type of fertilizer is made by covering water-soluble fertilizers such as urea, ammonium sulfate, potassium sulfate and ammonium phosphate chemical fertilizers with a coating material such as resin or sulfur, but all coating materials have no affinity with water. Such fertilizers have the disadvantage that they tend to float when applied to paddy fields or when flooded with water because of their poor water repellency and strong water repellency. In addition, even when applied to fields, it has the disadvantage that it is easily exposed to the soil surface by irrigation or rainfall. However, there is currently no research to eliminate these drawbacks. Various documents teach that surfactants can be used to impart hydrophilicity to highly repellent materials such as coating materials, but such methods do not allow the use of surfactants once placed in water or soil. The surfactant is washed away and the sustained hydrophilic effect is lost. Also, when a surfactant is added to the coating material, some effect is observed, but the effect is still not of a practical level. The inventors, including one of the inventors of the present invention, have repeatedly researched a treatment method that has a long-lasting and complete floating prevention effect based on water repellency, and have completed an invention,
The application was filed as No. 76683. This invention (hereinafter referred to as the prior invention) consists in a fertilizer in which fine powder and a surfactant are adhered to the surface of a granular fertilizer coated with a resin-containing coating material. The fine powders mentioned here include activated carbon powder, diatomaceous earth, iron oxide, clay, bentonite, and silicate, but in order to adhere these to the resin-coated granular fertilizer, the fertilizer must be coated with the coating. It is necessary to heat the coating to a temperature close to the fusion temperature of the coating, which can make it difficult to maintain proper manufacturing conditions, and the types of surfactants and HLB used for hydrophilic treatment are somewhat limited. There was a tendency to The present inventors have developed a hydrophilically treated coated granular fertilizer that has an effect equal to or better than that of the prior invention, is easy to manufacture, that is, hydrophilically treated, and has a wider selection range of surfactants to be used in combination, and a hydrophilic treatment method thereof. , researched extensively. As a result, instead of the fine powder referred to in the prior invention,
_SiO2 dust, mainly present in fumes from melting furnaces for pig iron, iron alloys and silicon metals
Fine powder made of SiO ₂ (hereinafter referred to as SiO ₂ dust)
The present invention was completed knowing that the above problem could be solved by using the following. As is clear from the above description, the first object of the present invention is to provide a coated granular fertilizer with good hydrophilicity and a method for treating the same with hydrophilicity. The second purpose is to develop an attachment method that allows fine powder materials to be attached to coated granular fertilizers (hereinafter sometimes simply referred to as coated fertilizers) without heating them to near the melting temperature of the coating material, and the fine powder used in that method. The present invention provides a hydrophilic coated fertilizer to which a surfactant and a surfactant are attached. Its other purpose is
This will become clear from the description below. The present invention provides (1) a hydrophilically treated coated granular fertilizer characterized in that SiO ₂ dust and a surfactant are attached to a coated granular fertilizer whose outermost layer is coated with a resin-containing coating material; and (2) a coated granular fertilizer containing a resin. A coated granular fertilizer coated with a coating material containing the material is held in a tumbling state, a fluid state, or a jet-flowing state, and SiO ₂ dust and a surfactant are applied separately or the surfactant is applied in advance.
This is a hydrophilic treatment method for coated granular fertilizer, which is characterized by mixing SiO ₂ dust and making it adhere to the coated granular fertilizer held in a tumbling, fluidizing or jetting state. Below, the configuration and effects of the present invention will be explained in detail. A coating material that covers the coated granular fertilizer used in the present invention; The coating material contains a resin as an essential component. Both thermoplastic and thermosetting resins can be used, and the resin is not limited to a particular one. Examples of coating material compositions containing the former include polyolefin resins, ethylene-vinyl acetate copolymer resins, and There are thermoplastic resins containing one or more vinylidene chloride resins. Thermosetting resins that can be used similarly include:
For example, there is a relatively soft fatty oil-dicyclobentadiene copolymer disclosed in Japanese Patent Publication No. 40-28927. Furthermore, although it is not an essential component for coating materials,
The following fine powders are components that can be used in combination with the essential component resin. Examples of the fine powder include inorganic fillers that are commonly used in various resin compositions to improve their physical properties or increase their weight. For example, metal oxides such as talc, calcium carbonate, iron oxide, and sulfur powder can also be used, although they are not so-called inorganic fillers. Coated granular fertilizer used in the present invention; The fertilizer may be a single fertilizer such as urea, ammonium sulfate, potassium sulfate, potassium phosphate or a fertilizer containing nitrogen, phosphoric acid,
A chemical fertilizer prepared by mixing two or more types of fertilizers so as to contain two or more components of potassium, which is granulated, is produced by coating it with the above-mentioned resin or resin composition by a known method. As a known method, the recommended method is, for example, as shown in Japanese Patent Publication No. 54-3104, in which a polyolefin resin solution is added to fertilizer particles and the solvent in the solution is instantly dried with a high-speed hot air stream. Method for attaching SiO ₂ dust and surfactant; SiO ₂ dust and surfactant are attached to the coated granular fertilizer prepared as described above.
Here, SiO ₂ dust is not just a fine SiO ₂ powder, but a special industrial waste or by-product obtained from the following sources. That is, the SiO ₂ dust is a fine powder mainly composed of SiO ₂ that is present in the fumes from a melting furnace for pig iron, iron alloys, or silicon metal. SiO ₂ dust is produced by oxidation of metal silicon and is a spherical particle with an average particle size of 0.05 to 0.15μ. Its main component is SiO ₂ with impurities such as Fe ₂ O ₃ , sl ₂ O ₃ ,
It contains CaO, C, MgO, etc., and its reaction is neutral to slightly alkaline. SiO ₂ dust that has been calcined to remove C (carbon content) and decolorized can also be used in the same way. The reason why this SiO ₂ dust is completely different from the "fine powder" referred to in the prior invention in terms of use is that when it is applied to the coated granular fertilizer, there is no need to heat the coating containing resin to the extent that it softens the coating. Yes (see Examples below). This property of SiO ₂ dust is not only a property that is completely absent from diatomaceous earth, talc, or clay, which is a fine powder used in the prior invention and is a silicate in a broad sense, but also a property of SiO ₂ dust. Use provides coated granular fertilizers according to the invention with superior effects over previous inventions. The method of adhering SiO ₂ dust to coated granular fertilizer is as follows:
This can be done without special heating for the reasons mentioned above. That is, a coated granular fertilizer coated with a resin-containing coating material is held in a tumbling state, a fluidized state, or a jet-flowing state, and SiO ₂ dust and a surfactant described below are separately applied or the surfactant is applied in advance. The SiO ₂ dust is mixed and applied to the coated granular fertilizer held in a tumbling, fluidizing or jetting state. The amount of SiO ₂ dust used is 0.01% by weight or more and 5.0% by weight, preferably 0.1% by weight, based on the coated granular fertilizer.
Weight% or more 1.0% by weight (All percentages below are weight%)
). In the mixing method, SiO ₂ dust is directly put into the granular fertilizer under rolling conditions, or dispersed in air or the like for forming a fluidized bed and then supplied into the fluidized bed of the granular fertilizer. The temperature of the rolling element or fluidized bed containing the granular fertilizer at the time of inputting or supplying is not limited, but is, for example, 20°C to 70°C, preferably 30°C to 60°C.
It is. Even if the temperature exceeds 70°C, at which the resin coating softens, there is no particular effect, and below 20°C, adhesion is insufficient and the effect may not be sufficient depending on the composition of the coating. In particular, if it is carried out at room temperature, such as 20°C to 25°C, the adhesion process is simplified and a sufficient effect can be obtained without the need for special heating, but depending on the specific type or composition of the resin film, the temperature may vary. Most favorable results are often obtained when maintained between 30° and 60°C. The mixing adhesion time is
Although not particularly limited depending on the dust deposition method, processing amount, and supply time, a time period of usually 10 seconds to 30 minutes, preferably 30 seconds to 10 minutes, is sufficient.
In addition, the pressure inside the adhesion mixer does not require special pressure; in the case of a rolling device, normal pressure is sufficient, and in the case of a flow device, a slight pressure is applied to maintain the required fluidity inside the device. For example, a water column of about 0.1 m to 3 m is sufficient. Next, unlike in the case of the prior invention, the type or HLB of the surfactant used in the present invention is different from that of the prior invention.
It is not particularly limited by. That is, anionic, cationic, amphoteric or nonionic surfactants can be used, and HLB values can range from 4 to 20 over a wide range. Specific examples of surfactants to be used include anionic surfactants such as higher alcohol sulfates, cationic surfactants such as polyoxyethylamines, amphoteric surfactants such as betaine, polyoxyethylene alkyl phenyl ethers, polyoxy There are various nonionic surfactants such as esters of ethylene glycol and fatty acids. These surfactants are preferably used in the present invention in liquid or solution form, and one or two types of surfactants are used in the present invention.
More than one type can be mixed or used in combination. The amount used is generally 0.01 to 20%, preferably 0.05%, based on the weight of the coated granular fertilizer.
~10%, but there are differences depending on the specific attachment method (described later ~). The attachment method is
After attaching SiO ₂ dust to the coated granular fertilizer, spraying a surfactant, spraying the surfactant on the fertilizer before the SiO ₂ dust is attached, and attaching the SiO ₂ dust to which the surfactant has been attached in advance to the fertilizer. Either is fine. In each of these cases, the amount of surfactant used is 0.01 to 20% based on the weight of the coating in each of the above cases.
Preferably 0.01-10% and 0.01-1% respectively
0.05-10%, 0.05-5%, 0.05-0.5%.
Further, the HLB value of the surfactant used is not limited as described above, but a HLB value of 6 to 16 is preferable. The specific manner in which the surfactant is attached to the coated granular fertilizer is as follows:
When spraying a surfactant after adhering SiO ₂ dust, the fertilizer is rolled in a pan granulator, drum granulator, etc., or fluidized in a fluidized tower or spouted bed tower. At the same time, a liquid or solution surfactant is dropped, sprinkled, or sprayed to uniformly adhere the surface active agent. The same applies to the fertilizer before the SiO ₂ dust is attached. _SiO2 to coated granular fertilizer after surfactant adhesion
The dust can be attached in the same manner as before the agent is attached. In addition, when using SiO ₂ dust to which a surfactant has been attached in advance to the coated granular fertilizer, the fertilizer is placed in the rolling, flowing or jetting state as described above, similar to the above case. However, it is necessary to separately attach a surfactant to the SiO ₂ dust. That is, a method of adding a liquid surfactant or a surfactant solution while stirring SiO ₂ dust, or a method of sequentially adding SiO ₂ dust to a liquid surfactant or a surfactant solution under stirring. Since SiO ₂ dust is an ultrafine particle, it tends to aggregate and has poor dispersibility, but by mixing it with a surfactant, the poor dispersibility can be improved. The mixing conditions in these and cases are not particularly limited, but 0°C to 50°C, preferably room temperature to 35°C, reduced pressure of 100mmHg to 2Kg/cm ² G, preferably normal pressure for 1 minute to 1 hour, preferably 3
It takes between 30 minutes and 30 minutes. The mixing conditions for adhering the surfactant to the SiO ₂ dust in advance are substantially the same as the conditions described above for adhering the SiO ₂ dust. The SiO ₂ dust used in the present invention can also be mixed with other fine powders such as talc, calcium carbonate, diatomaceous earth, etc., and this mixture improves the dispersibility of the SiO ₂ dust itself. Therefore, there is an advantage that mixing for the above-mentioned ~ is facilitated. In order for the mixture to maintain the same effect as using SiO ₂ dust alone, the weight ratio of SiO ₂ dust in the mixture should be 40% of the mixture.
Preferably, it is 50% or more. The conditions for using such a mixture (temperature, pressure, time) are the same as those for the deposition conditions described in ~. It is also possible to adhere SiO ₂ dust and other fine powders separately so that the amount of adhesion is in the above ratio, but in that case, the resin coating of the coated granular fertilizer is removed in the process of attaching only the other fine powders. This creates a need to heat the temperature to near its fusion temperature. Hydrophilicity of the coated granular fertilizer of the present invention: The coated granular fertilizer of the present invention has excellent hydrophilicity, that is, the property of not floating on water during application, as shown in the Examples below. The reason why this fertilizer has such hydrophilicity is unknown, but it is probably because the SiO ₂ dust adhering to the surface of the fertilizer is extremely fine particles, so that the individual particles of the coated granular fertilizer are This is thought to be because the particles aggregate on the surface, and as a result, a kind of porous-like coating layer is formed on the surface by aggregates of SiO ₂ dust. It is assumed that when the coated granular fertilizer comes into contact with water, the coating layer absorbs water due to a cooperative effect with the coexisting surfactant, and the surface of the fertilizer becomes covered with a water film. . The coated granular fertilizer of the present invention maintains its hydrophilicity without immediately losing its hydrophilicity when immersed in water, unlike when an untreated coated granular fertilizer is simply treated with a surfactant alone. This means that the surfactant on the surface of the fertilizer of the present invention is not easily eluted and lost even when immersed in water. Although the reason for this is also unclear, it is thought that a type of bond such as a hydrogen bond acts between the surfactant and the coexisting SiO ₂ dust. This is because it is presumed that the surface of the SiO ₂ dust is in a substantially activated state. Whether or not the coated granular fertilizer of the present invention is imparted with hydrophilicity can be easily confirmed by placing the coated granular fertilizer in a container and gently pouring water into the container. If hydrophilicity is imparted, the fertilizer will sink in water because the surface of the fertilizer gets wet and the specific gravity of the fertilizer is greater than the specific gravity of water.
If the hydrophilicity is not imparted or is insufficient, the fertilizer will not be able to settle due to the surface tension of the water and will float to the surface of the water. Whether or not the fertilizer has such persistent hydrophilicity can be confirmed by repeating the water injection test described above. The coated granular fertilizer of the present invention is clearly superior to the Comparative Examples described below in that it has a durable hydrophilic property that can withstand the above-mentioned repeated tests. The present invention will be explained below with reference to Examples. In the examples, granular urea is used as the coated granular fertilizer, but it goes without saying that the present invention can also be used with other single or composite fertilizers. Example 1 This example shows a method of attaching SiO ₂ dust etc. to the surface of coated granular fertilizer. FIG. 1 shows a jet device used to deposit SiO ₂ dust, etc. in this example. 1 is a jet tower with a tower diameter of 250 mm and a height
2000 mm, the air outlet diameter 1' is 50 mm in diameter, and has a fertilizer input port 2 and an exhaust gas discharge port 3. The jet air is sent from the blower 7, passes through the orifice flowmeter 6 and the heater 5, and reaches the jet tower.The flow rate is controlled by the flowmeter, the temperature is controlled by the heater, and the exhaust gas is led out of the tower from the outlet. The coated granular fertilizer to be attached to the surface is introduced through the input port while a predetermined amount of air is flowing. When the coated granular fertilizer to be treated reaches a predetermined temperature, the SiO ₂ dust, etc. contained in the SiO ₂ dust hopper 8 is sent to the SiO ₂ dust disperser 10 by the micro feeder 9. The SiO ₂ dust disperser has a structure that blows out high-velocity air at the part where it comes into contact with the SiO ₂ dust, and the SiO ₂ dust is uniformly dispersed in the air, reaches the jet tower, and is circulated within the tower. It comes into contact with particles in the air column and adheres to the surface. When a predetermined amount of adhesion is reached, the microfeeder is stopped, the pressurized air and the floor are stopped, and the product is extracted from the extraction port 4. In this example, processing was carried out while maintaining the following basic conditions. Hot air volume ^4m3 /min Input amount 10Kg Fertilizer particle size 5-7mesh (coated spherical urea with coverage rate 5wt%) Supply rate of SiO ₂ dust, etc. 50g/min Processing time 10min Note that 11 in Figure 1 is the spray nozzle, 12 is the spray nozzle, and 12 is the spray nozzle. A pump and a tank 13 are used to send the surfactant, and when the surfactant was introduced from Example 2 onwards, it was introduced through this nozzle. Example 2, Comparative Example 1 This example shows that the effects of the present invention can be obtained even when the SiO ₂ dust used in the present invention is deposited at a low temperature. In Example 1, polyethylene was used as the covering material.
A surfactant (5 g of hexaoxyethylene nonyl phenyl ether (1% by weight of the coating)) was added to granular urea coated with a coating material consisting of 90 parts of ethylene-vinyl acetate copolymer and 10 parts of ethylene-vinyl acetate copolymer. After uniformly coating the surface, 30 g of SiO ₂ dust or diatomaceous earth as a comparative example (0.3% by weight of fertilizer) was deposited at the particle temperature shown in Table 1. 5 g of each treated product (counting the number of particles) (approximately 30 grains per gram) were placed in a shear dish with a diameter of 15.5 cm and a height of 3 cm, and water was gently poured along the shear wall to determine the percentage of the number of grains that floated to the surface (floating rate).After this test, the particles remained overnight. After leaving it for a while, the entire amount of water was extracted and the test to determine the floating rate was repeated 10 times, three times each time.Table 1 shows the test results for the present example and comparative example (using diatomaceous earth). When SiO ₂ dust was used, a sustained effect was observed even when deposited at low temperatures (e.g. 30°C), but when diatomaceous earth was used, a sustained effect was observed even when deposited at 70°C. No effect was observed.Although this example uses resin alone as the coating material, it was also possible to use a coating material composition consisting of polyethylene, ethylene vinyl acetate copolymer, talc, and sulfur, and to use urea or other granular fertilizers. Similar results were obtained when a coated material was treated in the same manner.

【table】

[Table] Comparative example product: one using diatomaceous earth Example 3 This example shows the relationship between the amount of SiO ₂ dust used and the effects of the present invention. In Example 1, polyethylene was used as the covering material.
A chemical fertilizer consisting of potassium sulfate and diammonium phosphate (N=
13.0, P ₂ O ₅ = 13.0, K ₂ O = 13.0) and SiO ₂ dust was applied to the coated particles maintained at 60° C. at the feed rates shown in Table 2. Next, in a jet state, an amount (10 g) of a surfactant (octaoxyethylene nonyl phenyl ether) equivalent to 1% of the coating material was dispersed in 10 times the amount of methanol, and added to the coated particles using a spray nozzle. Ta. Table 2 shows the results of the treated products obtained with this sample, and the effect was recognized even with a trace amount of SiO ₂ dust of 0.01% based on the coated fertilizer.

This was done using the method in [Table]. The data is
The 5th ascent rate is shown.
Example 4 This example describes the relationship between the amount of surfactant used and the effects of the present invention. 100 kg of granular urea coated with a coating material composition consisting of 30 parts of polyethylene, 20 parts of ethylene-vinyl acetate copolymer, and 50 parts of sulfur was placed in a concrete mixer, heated and maintained at 50°C to remove 300 kg of SiO ₂ dust.
g (0.3% by weight of the coated granular fertilizer) was added and the mixer was rotated for 5 minutes to allow it to adhere. Next, a surfactant as shown in Table 3 was added to the fertilizer in the form of a spray, and the obtained product was continuously tested for antiflotation effect based on the flotation rate measurement method shown in Example 2. Table 1 shows the test results, and it is recognized that the surfactant acts effectively even at a small amount, such as 0.01% of the coating weight.

[Table] Tested by scattering.

[Brief explanation of the drawing]

Figure 1 is a schematic vertical cross-sectional view of the device used in Example 1 to attach SiO ₂ dust to the coated fertilizer surface, and Figure 2 is an enlarged view of the microfeeder and SiO ₂ dust disperser. FIG. 1... Jet tower, 1'... Air spout, 2... Fertilizer inlet, 3... Exhaust gas outlet, 4... Fertilizer outlet, 5... Heater, 6... Orifice flow meter, 7
...Blower, 8...SiO ₂ dust hopper, 9
... Micro feeder, 10 ... SiO ₂ dust disperser, 11 ... Spray nozzle, 12 ... Pump,
13...Tank.

Claims (1)

[Claims] 1. A coated granular fertilizer subjected to hydrophilic treatment, characterized in that SiO ₂ dust and a surfactant are attached to a coated granular fertilizer whose outermost layer is coated with a resin-containing coating material. 2. The resin used is selected from polyolefin resin, olefin copolymer resin, ethylene-vinyl acetate copolymer resin, polyolefin wax, paraffin wax, or alkyd resin.
The fertilizer according to claim 1, which is the above. 3. The fertilizer according to claim 1, wherein the SiO ₂ dust used is a fine powder mainly composed of SiO ₂ present in the fumes from a melting furnace for pig iron, iron alloys, or metal silicon. 4. The fertilizer according to claim 1, wherein the surfactant used is an anionic, cationic, amphoteric or nonionic surfactant. 5 A coated granular fertilizer coated with a resin-containing coating material is kept in a tumbling state, a fluidized state, or a jet-flowing state, and SiO ₂ dust and a surfactant are applied separately or SiO ₂ dust is coated with a surfactant in advance. 1. A method for hydrophilic treatment of coated granular fertilizer, which comprises mixing and adhering the coated granular fertilizer to the coated granular fertilizer maintained in a tumbling, fluidizing or jetting state. 6. Claim 5, wherein the resin used is one or more selected from polyolefin resins, olefin copolymer resins, ethylene-vinyl acetate copolymer resins, polyolefin waxes, paraffin waxes, and alkyd resins. the method of. 7. The method according to claim 5, wherein the SiO ₂ dust used is a fine powder mainly consisting of SiO ₂ present in the fumes from a melting furnace for pig iron, iron alloys or silicon metal. 8. The hydrophilic treatment method according to claim 5, wherein the surfactant used is an anionic, cationic, amphoteric, or nonionic surfactant.