JPS5845188A - Manufacture of coated granular fertilizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method for producing coated granular fertilizer.

Although chemical fertilizers are fast-acting, they are essentially water-soluble, so losses due to drainage, denitrification, etc. are large, and it is difficult to maintain their fertilizing effect over a long period of time. When doing so, there are edicts that cause concentration problems to crops. For this reason, various slow-release fertilizers in which granular fertilizers are coated with resin have been proposed. These coated granular fertilizers are manufactured by two methods. One is a method in which granular fertilizer is coated with a solution of a synthetic resin dissolved in an organic solvent, and the other is a method in which the fertilizer is coated with a melt of a resin having a relatively low melting point. However, according to the former method, the product is expensive because it uses organic solvents, and there is a risk of fire and pollution caused by wiping during manufacturing.
According to the latter method, since a hot melt is used, the granular fertilizers tend to adhere to each other during coating and form into n-granules. In order to solve these problems, some proposals have been made to use aqueous resin emulsions, but as mentioned above, chemical fertilizers are water-soluble, so emulsions can be used to provide granular fertilizers with the required coverage. It is extremely difficult to coat the material, and it has not yet been put to practical use. Furthermore, even if resins are suitable as coating materials for granular fertilizers, some resins do not stably form emulsions.

The present invention has been made to solve the above-mentioned problems, and is a method for producing coated granular fertilizer coated with a resin using an aqueous emulsion containing an organic solvent, such as an aqueous emulsion of a phase inversion emulsified thermoplastic resin. The purpose is to provide

In the present invention, as a first step, a water-resistant resin coating is formed on the granular fertilizer at a coverage rate of α1 to 2− using an aqueous emulsion or an organic solution of a thermoplastic resin.

The second step is characterized in that the granular fertilizer is resin-coated with an aqueous emulsion of a thermoplastic resin containing an organic solvent at a required coverage rate.

In the present invention, as a first step, a water-resistant resin coating is formed on each granular fertilizer using an aqueous emulsion or an organic solution of a thermoplastic resin so that the coverage is in the range of 0.1 to 2 inches. Here, the coverage rate (a) is defined as (amount of resin used/(amount of fertilizer used and amount of resin used))×100. The emulsion used in the first step may be one that does not contain an organic solvent or may contain an organic solvent.

As the emulsion containing an organic solvent, for example, an emulsion obtained by dissolving a resin and a surfactant as an emulsifier in an organic solvent, gradually adding water to this solution with stirring, and causing phase inversion is suitable. used. According to the present invention, by using an emulsion containing an organic solvent in at least the second stage, it is possible not only to coat the granular fertilizer with a resin even if the resin is difficult to form a stable emulsion. Compared to the case where a resin solution is used in the second step, a large amount of organic solvent can be saved, and the safety during carving is also improved.

According to the present invention, by setting the coverage rate of the granular fertilizer in the first stage within the above range, even if an aqueous resin emulsion is used as the coating material in the first stage, one granular fertilizer will not be dissolved, and #water-based By forming a water-resistant resin film on the granular fertilizer at a coverage rate within the above range, it is possible to form a resin film on the granular fertilizer at a coverage rate within the above range. This is because it no longer dissolves. In order to form a water-resistant resin coating on a granular fertilizer in the first stage, the granular fertilizer is preferably rolled on a rotating pan and heated with hot air, while a resin emulsion or solution is sprayed onto the granular fertilizer with a spray gun. Spray by etc. In this case, when an aqueous emulsion of a thermoplastic resin is used as the coating material, the critical temperature at which the resin forms a continuous film, that is, the minimum film formation temperature, is 5 to 80°C.
It is desirable to maintain the granular fertilizer at a high temperature by blowing hot air to quickly form a water-resistant resin coating of the water-based emulsion and to suppress the water-soluble granular fertilizer from being washed away. In addition, when using an organic solution of thermoplastic resin as a coating material, the temperature of one granular fertilizer is not particularly limited;
Preferably, the temperature is 60 to 70°C, and by enlarging the base of the hot air, it is possible to effectively prevent the fertilizer from becoming 1a grains during the formation of the resin film.

Emulsions that can be used in the present invention are not particularly limited, but include, for example, low molecular weight polyethylene emulsions, ethylene-α-olefin copolymer emulsions, polyvinylidene chloride and copolymer emulsions, ionomer resin emulsions, ethylene-vinyl acetate copolymer emulsions, etc. Examples include a combined emulsion, a polyvinyl chloride emulsion, an emulsion of polyacrylic acid, polymethacrylic acid, and copolymers thereof. Although not particularly limited in the present invention, the minimum film forming temperature is 100
An emulsion having a temperature of 0.degree. C. or less is preferably used. As mentioned above, the method of the present invention is advantageous for coating granular fertilizers with resins that are difficult to form stable emulsions, and examples of such resins include ethylene-niolefin copolymers, acetic acid silica, etc. Examples include ethylene-M vinyl acetate coelectrolyte having a content of 88Ii1 or less. The resin concentration in the emulsion is not particularly limited, but is 5 to 15
A weight of about 100 liters is suitable.

When using a resin solution in the first step, the resin used is not particularly limited, but usually polygtadine, ethylene-
Vinyl acetate copolymer, low molecular foot polyethylene, ethylene-α-olefin co-&combination.

Paraffin wax, amorphous polypropylene, chlorinated paraffin, etc. are used, and the solvents are toluene, benzene, xylene, hebutane, and octane.

Ethylcyclohexane, trichloroethylene, tetrachlorethylene, methylchloroform, carbon tetrachloride, tetrachlorethane, tetrahydro-7rane, etc. are used as appropriate. The resin concentration in the resin solution is also not particularly limited, but a concentration of approximately 100% s-go is usually appropriate.

In the present invention, the coating material, which is an emulsion or an organic solution of a resin, is added with a surfactant to control the elution rate of the fertilizer from the coated granular fertilizer.
1 to 25 iifi parts per 0 parts by weight, preferably 5 to 20 parts by weight
Contains parts by weight. Commercially available products manufactured by emulsification stand:
Sweat emulsions contain a surfactant in advance, and therefore, in the present invention, these commercially available emulsions can be used as they are in the first step, but if necessary, one more surfactant may be added. It's okay. As mentioned above, the emulsion used in the second step is preferably prepared by phase inversion emulsification of the resin solution with an emulsifier and water, so if the type and amount of the surfactant used during this preparation are appropriately selected good. Preferred surfactants include dialkyl sulfosuccinate sodium salt, higher alcohol sulfate ester sodium salt, and sodium dodecylbenzenesulfonate.

Examples include alkyl bicolinicum chloride, polyoxyethylene alkylphenyl ether nabuate ammonicum salt, and the like.

In this way, the granular fertilizer that has formed a water-resistant film at the coverage rate α1-2 at the M1 stage is then coated with a thermoplastic resin containing an organic solvent to the coverage rate required to achieve the fertilizer's effectiveness. Resin coating is carried out as in the first stage using an aqueous emulsion. The coverage rate depends on the type of fertilizer and the degree of edge effectiveness required, but is usually in the range of 2 to 8 O<->, preferably 3 to 1 O<->. The humidity of the granular fertilizer at the time of resin coating in the second stage is determined by the minimum film forming temperature of the resin emulsion used, which can prevent the fertilizer from agglomerating. Note that the resin used in the second stage may be the same as or different from that in the first stage.

Granular IP! Although the particle size of the material is not limited at all, it is preferably about 3 to 10 mIn in order to avoid agglomeration during resin coating.

According to the method of the present invention, as described above, in the first step, a resin film is formed on the granular fertilizer at a coverage rate of 1 to 2%, so in the second step, an aqueous resin emulsion is used to cover the required amount. It is possible to resin-coat granular fertilizers up to the coverage level, thus significantly reducing the usage of organic solvents compared to the case of using resin solutions, significantly reducing manufacturing costs, and improving safety during manufacturing. is enhanced.

Furthermore, the coated granular at: material obtained by the method of the present invention allows the rate of fertilizer elution to be controlled by selecting the resin and the final coverage, as shown in the examples.

Examples of the present invention are listed below, but the present invention is not limited thereto. In addition, in the following, parts indicate 1 part by weight.

Example 1a Ethylene-α-olefin copolymer (Y7MAM-20
090, manufactured by Mitsui Petrochemical Industries, Ltd.) and 100 parts of polyethylene alkylphenylpurphate ammonicum salt (No.
5 parts of Hytenol 17) manufactured by Kogyo Charge ■ and 20 parts of toluene
Firstly, 150 parts of water was gradually added dropwise while stirring due to this dissolution, and the resin concentration was reduced to zL7wj19 by phase inversion emulsification.
An aqueous emulsion (minimum film-forming temperature of 80 to 88°C) of g was obtained.

As the first step, 200 tons of granular fertilizer with an average particle size (5 mm) was put into a rotating pan and heated to 90°C with hot air while being transferred.Next, the above emulsion was intermittently applied to this granular fertilizer with a spray gun. The M degree of one granular fertilizer is 85.
While keeping it at ~9G'C.

Coverage rate LOIs were coated. Next, while maintaining the temperature of this granular fertilizer at 80 to 88° C. with hot air, the same emulsion as above was sprayed with a solid content of 109°C.

A coated granular fertilizer with a coverage rate of 54% in the second stage was obtained.

Coated granular fertilizers were obtained in exactly the same manner as above using coating materials containing different amounts of surfactants in the emulsions. The fertilizer dissolution rate C or less after 24 hours when these fertilizers are immersed in water at 80°C is simply referred to as the dissolution rate. ) are shown in the table below, and the change in elution rate with respect to the immersion period is shown in the drawing. It will be apparent that by adjusting the amount of surfactant in the emulsion, the amount of elution can be controlled.

Example 1b As a first step, the same granular fertilizer 2002 as in Example 1a was placed in a rotary pan, heated to 90°C with hot air while rolling, and then a 10-titoluene solution of polygetadiene was intermittently sprayed to form the granular fertilizer. While maintaining the temperature of the fertilizer at 85 to 90°C, the fertilizer was coated at a coverage rate of α5-. Next, as a second step, Example 1
A coated granular fertilizer with a coverage of about 5 times was obtained in the same manner as in Example 1a using emulsions having different amounts of surfactants in the same manner as in Example 111. The elution rate of the fertilizer thus obtained is shown in the table.

Example 2 Polyvinyl chloride (Zeon 181 manufactured by Nippon Zeon ■) 100
! 1. 45 parts of dioctyl phthalate (manufactured by Tokyo Kasei) and polyethylene glycol sorbitan mono 2 quarts (
5 parts of Nurgen TV10 (manufactured by Daiichi Kogyo Seiyaku) was dissolved in 100 parts of toluene, 20 parts of water was gradually added dropwise to this solution with stirring, and phase inversion emulsification was carried out to achieve a resin temperature of [22.2 wt. An emulsion (minimum film formation temperature of 50 to 6 fJc) was obtained.

As the first step, the granular fertilizer was heated to 90°C by the same method as in Example 1a, and then the emulsion was sprayed intermittently to maintain the temperature of each granular fertilizer at 70 to 75°C, with a coverage of 1 inch. A water-resistant resin film was formed. As a second step, the same emulsion as above was sprayed while maintaining the temperature of this granular fertilizer at 55 to 60°C to obtain a coated granular fertilizer with a coverage rate of 7.0-. The dissolution rate of this fertilizer was 24-.

Example 8 100 parts of ethylene-vinyl acetate copolymer (Evaflex P-8807, manufactured by Mitsui Polygummy Careu) and 5 parts of polyoxyethylene alkylphenyl ether sal 7 ate ammonicum salt (manufactured by Daiichi Kogyo Seiyaku ■, Hi; Nor 17) was dissolved in 150 parts of toluene, and then 200 parts of water was gradually added dropwise to this solution while stirring, and the resin concentration was adjusted to 8 by phase inversion emulsification.
&0% by weight emulsion (minimum film formation temperature 70-75℃
) was obtained.

In the same manner as in Example 1a, after preheating the granular fertilizer to 90°C, the above emulsion was intermittently sprayed while maintaining the temperature at 70 to 75°C to form a resin film at a coverage rate of 1.0%. . Next, as the second step, the temperature of the granular fertilizer is set to 40~
While maintaining the temperature at 45° C., the emulsion was intermittently shaken to obtain a coated granular fertilizer with a coverage rate of &0. The elution rate of this fertilizer was 28s.

Example 4 After dissolving 100 parts of acrylic ester (Aron T g000B manufactured by Toagosei Kagaku Kogyo ■), part A of sodium dodecylbenzenesulfonate (Neodan R manufactured by Daiichi Kogyo Seiyaku ■) in 100 parts of toluene.

Phase inversion emulsification was carried out with 200 parts of water to obtain an emulsion with a resin concentration of 248 parts by weight (minimum film forming temperature of 60 to 65 parts).

In the same manner as in Example 1IL, after heating the granular fertilizer to 90°C, while maintaining the temperature at 80 to 85°C, the above emulsion was intermittently sprayed, and the tips were coated with resin at a coverage ratio of toe. next,
The above emulsion was sprayed while maintaining the temperature of the granular fertilizer at 60 to 65°C to obtain a coated granular fertilizer with a coverage rate of 5.0. The dissolution rate of this fertilizer was 81-.

[Brief explanation of the drawing]

The figure is a graph showing a fertilizer dissolution rate curve when the coated granular fertilizer obtained in Example 1a of the present invention is immersed in water at 80°C. Patent Applicant Nitto Electric Industry Co., Ltd. Agent Patent Attorney Maki Shuubu - (・MU) 4 Department 15 壬

Claims (2)

[Claims] (1) In the first step, a water-resistant resin film is formed on the granular fertilizer with a coverage of Al-2% using a thermoplastic resin water-based resin or an organic solution, and then in the second step, a thermoplastic resin film containing an organic solvent is formed. A method for producing a coated granular fertilizer, which comprises coating the granular fertilizer with a resin at a required coverage rate using an aqueous resin emulsion. (2) When forming a resin film on the granular fertilizer using an emulsion in the first stage, the granular fertilizer is heated to a temperature 5 to 30°C higher than the minimum film formation temperature of the emulsion, and the second stage
When applying resin coating due to neglecting the steps. A method for producing a coated granular fertilizer according to claim 1, characterized in that the granular fertilizer is heated to the lowest film-forming temperature of the emulsion used.