JP2001031489A - Degradable film-coated fertilizer excellent in preventing property of floating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coated fertilizer having a high level of elution controllability, photodecomposability, biodegradability and practical strength of a coating film and excellent in preventing properties of floating by coating a fertilizer with the coating film comprising a photodecomposition catalyst and modifying the surface of the coated fertilizer with silica and/or a surfactant. SOLUTION: A photodecomposition catalyst is preferably a metal organic complex selected from iron, cobalt, nickel, zinc and tin and preferably nickelbis- diethyl dithiocarbamate, tris-acetylacetoneison or the like. The coating film is preferably an α-olefin (co)polymer, an α-olefin-vinyl ester copolymer or the like from aspects of elution controllability and strength. The amount of the photodecomposition catalyst is preferably 0.05 to 50×10-6 mol/g based on the weight of the whole coating film material and the amount of silica is preferably 0.1-5 wt.% based on the coated fertilizer. The amount of the surfactant is preferably 0.01-5 wt.% based on the coated fertilizer. Although a low-molecular weight polyethylene is preferred from the viewpoint of the biodegradability, the mechanical strength causes a problem. Thereby, the coexistence of the α-olefin-vinyl ester copolymer or the like is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated fertilizer, and more particularly to a coated fertilizer which is excellent in controlling the dissolution of fertilizer components, is excellent in decomposability of its coating in a natural environment, and has sufficient strength for practical use. Also, the present invention relates to a coated fertilizer having excellent floating resistance when used in paddy fields and the like.

[0002]

2. Description of the Related Art Coated fertilizers have been used in a wide variety of agricultural fields from the viewpoints of labor saving of fertilization, regulation of fertilizer efficiency according to plant growth, and measures against environmental pollution by excessive fertilizer components. As the coated fertilizer, a granular fertilizer whose surface is coated with an inorganic substance such as sulfur, a thermosetting resin, a thermoplastic resin, or the like is used, and different fertilizer components and elution periods depending on crops are used. Have been.

[0003] This coated fertilizer is required to have some performance. First, the elution control, which is the original performance, is accurately performed. In particular, it is important to control the elution of fertilizer components during the initial period and during the initial stage, and if this control is not performed accurately, the crop will die if the fertilizer components elute excessively In this case, it causes poor growth. Since the dissolution rate is usually affected by the temperature, the dissolution type is designed in consideration of the temperature.

[0004] Next, it is necessary that the coated fertilizer has a coating strength that has no practical problem. Coated fertilizers are subjected to a number of mechanical stresses before they can be put to practical use. These include the strength against pressure and friction during storage and transportation, and the mechanical strength against the fertilizer. If the strength is not above a certain level, the coating may be damaged or the like, so that the original dissolution controllability may not be exhibited.

[0005] Recently, it has been pointed out that a coating of the coated fertilizer is deposited in the soil or flows out into a river. In order to cope with such a problem, attempts have been made to design such that the residual film is decomposed in a natural environment. As means for disassembling, JP-A-10-
1386, a method of applying oxidative decomposition, a technique of imparting photodegradability to a film using a metal complex having photocatalytic activity as described in JP-B-7-91143, Further, a method of applying a biodegradable resin such as polyester, polylactic acid, and polycaprolactone is known.

[0006] Among these, the method of applying photolysis is as follows.
Although it has the disadvantage that the decomposition rate is slow in soil that is not exposed to light, it is less susceptible to the concentration of microorganisms in the soil and has a relatively stable decomposition rate compared to biodegradation.

[0007] Further, the development of a coating having a higher and more stable degradability by some combination of oxidative decomposition, photodecomposition, and biodegradation has been promoted. For example, a film having both photodegradability and biodegradability is disclosed in JP-A-10-231190.
And JP-A-11-130576.

On the other hand, when the coated fertilizer is applied in a paddy field or the like, it is required that the coated fertilizer does not float on water.
If the surface rises, the risk of runoff from the drainage outlet increases, and not only sufficient fertilizer effect cannot be obtained but also a factor that may deteriorate the environment. As a technique for preventing the floating of the coated fertilizer, Japanese Patent Application Laid-Open No. 55-23045 discloses a technique of applying metal powder to the surface of a fertilizer.
Japanese Patent No. 120597 discloses a technique of attaching an anionic surfactant to the particle surface, and Japanese Patent Publication Nos. 63-23160 and 64-9278 discloses a technique of applying silica dust and a surfactant. ing.

As described above, a high degree of elution controllability required for coated fertilizers, degradability by light of the coating, preferably a performance having degradability other than photodegradability such as biodegradability, and a higher physical coating. For conventional performance requirements such as strength and anti-floating properties, some of the conventional coated fertilizers have certainly reached a certain level, but coated fertilizers that simultaneously satisfy all of these performances Yes had not been provided yet.

[0010]

The problem to be solved by the present invention is, as described above, to have a high degree of dissolution controllability, and to degrade the coating film by light, preferably biodegradability. Another object of the present invention is to provide a coated fertilizer having the property of having the decomposability of sapphire and having a practically sufficient strength and also having excellent floating prevention properties.

[0011]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventor has found that, in a coated fertilizer coated with a coating containing a photolysis catalyst, a specific substance, preferably The present inventors have found that a coated fertilizer modified in a specific amount can solve the above problems, and have completed the present invention.

That is, the present invention provides a coated fertilizer coated with a film containing a photolysis catalyst, wherein the surface of the coated fertilizer is modified with silica and / or a surfactant.

The photodecomposition catalyst in the present invention is at least one selected from iron, cobalt, zinc, nickel, copper, tin, manganese, silver, palladium, molybdenum, chromium, tungsten, and cerium. Means an organic complex of a metal. Examples of complexing agents that form the metal organic complex include β-diketones such as acetylacetone, β-ketoesters, dialkyldithiocarbamates, dialkyldithiophosphates, alkylxanthates, and mercaptobenzothiazoles.

Among these, iron, cobalt, nickel,
Preferable examples include organic complexes of metals selected from zinc and tin, and specific examples include nickel bis-diethyldithiocarbamate, nickel bisdibutyldithiocarbamate, and iron tris-acetylacetone.

The organometallic complex may be contained as a photodecomposition catalyst in one kind or in combination of two or more kinds.
The amount of these photolysis catalysts is 0.05% based on the total coating material weight.
５０50 × 10 −6 mol / g, more preferably 0.1-20 × 10? -6 mol / g. Below these preferred ranges the photodegradability of the coating will be slow, while
If it exceeds this range, a problem may occur in the control of dissolution when surface fertilization is performed.

The coating of the coated fertilizer of the present invention is a coating comprising the above-mentioned photolysis catalyst, a thermosetting or thermoplastic polymer and, if necessary, a filler and other additives.
Among them, use of a thermoplastic polymer is a preferred embodiment for achieving the object of the present invention.

As the thermoplastic polymer, polyethylene,
Α-olefin (co) polymers such as polypropylene, polybutene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, etc. (letters in parentheses may or may not be read The same applies hereinafter) α-olefin-vinyl ester copolymers such as ethylene-vinyl acetate copolymers, vinyl halide polymers such as polyvinyl chloride and polyvinylidene chloride, and poly (methyl (meth) acrylate) Alkyl (meth) acrylates and their copolymers, α-olefin-acrylate (co) polymers such as ethylene-ethyl acrylate, polymers of aromatic vinyl compounds such as styrene, polylactic acid, polycaprolactone, and aliphatic And polyesters of a dicarboxylic acid and a diol.

Of these, α-olefin (co) polymers and α-olefin-vinyl ester copolymers are preferred from the viewpoints of elution controllability and strength. Of the α-olefin (co) polymers, polyethylene is preferred, and low molecular weight polyethylene is more preferred because it has biodegradability. When low-molecular-weight polyethylene is contained, this alone causes a problem in mechanical strength. Therefore, α-olefin (co) polymer such as other ethylene-octene copolymer or α-olefin such as ethylene-vinyl acetate copolymer It is preferable that an olefin-vinyl ester copolymer and the like coexist.

Examples of the thermosetting polymer include conventionally known urethane resins, alkyd resins, melamine resins, epoxy resins and phenol resins.

Fillers include inorganic and organic fillers. As the inorganic filler, metal oxide sulfur powder such as talc, clay, calcium carbonate, diatomaceous earth, and titanium oxide can be used. The same silica as the surface-treated silica may be contained in the coating. The amount of these inorganic fillers is preferably 70% or less based on the total weight of the coating material. Above this level, the coating strength is greatly reduced and the practicality is poor.

Examples of the organic filler include starch, oxidized starch, and modified starch, cellulose and carboxyl-modified cellulose, agar, xanthone, and the like. The amount of these organic fillers is preferably 40% or less based on the total weight of the coating material. Above this, it becomes difficult to control elution. Organic fillers may also be used as a dissolution rate regulator for the initial dissolution-suppressed coated fertilizer.

Other additives include a dissolution controlling agent, a coloring agent, an anti-caking agent and the like. As the elution modifier, conventionally known cationic, nonionic, or anionic surfactants can be used. As described below, the elution modifier contained in the coating may be the same as the surfactant modified on the surface of the coated fertilizer. It was confirmed that the elution control agent used in the coating material of the coated fertilizer had an extremely small floating prevention effect as compared with the case where the surface was modified. As the coloring agent, coloring pigments and dyes such as carbon black and titanium white can be used.

The coated fertilizer of the present invention is a coated fertilizer obtained by modifying the surface of such a coating with silica and / or a surfactant. The silica in the present invention refers to a fine powder containing silicon oxide as a main component. In addition to silicon oxide, iron, magnesium,
Compounds such as calcium, sodium, and carbon may be contained. Silica particle size is 0.01 to 10
About 0 μm is preferable. So-called silica dust or fumed silica generated in a pig iron or iron alloy melting furnace has a small particle size and can be suitably used in light of the object of the present invention.

The amount of such silica is 0.1
To 5% by weight, more preferably 0.1 to 5% by weight.
2-3% by weight. Above this range, the effect of the photolysis catalyst is adversely affected. On the other hand, below this range, it is difficult to obtain an effective floating prevention effect.

In the present invention, the surfactant modified on the surface of the coated fertilizer refers to a cationic, nonionic, or anionic surfactant, and includes conventionally known surfactants. Examples of the nonionic surfactant include alkyl esters or alkyl ethers of polyethylene oxide, and alkyl esters or alkyl ethers of polypropylene oxide. Examples of the anionic surfactant include an alkylsulfonic acid and an alkylbenzenesulfonic acid. Examples of the cationic surfactant include quaternary ammonium salts such as trimethylalkylammonium chloride. Among them, nonionic and anionic surfactants can be preferably used.

These surfactants can be used alone or in admixture of two or more. The amount of such a surfactant is preferably 0.01 to 5% by weight, more preferably 0.1 to 2% by weight, based on the coated fertilizer. Exceeding this range makes it difficult to obtain an effective effect of the photolysis catalyst. On the other hand, if this round is used, the effective floating prevention effect is inferior. The silica and the surfactant which are modified on the surface of the coated fertilizer of the present invention exert the effect of the present invention on either one thereof, but may be modified on both.

There is no particular limitation on the fertilizer component present inside the coating of the coated fertilizer in the present invention, and conventionally known fertilizers can be used. Specific examples include urea, aldehyde condensed ureas such as formaldehyde condensed urea, isobutyraldehyde condensed urea, guanyl urea sulfate, lime nitrogen,
Ammonium compounds such as ammonium nitrate, ammonium sulfate, ammonium chloride, ammonium dihydrogen phosphate and diammonium hydrogen phosphate; potassium salts such as potassium nitrate, potassium chloride and potassium sulfate; calcium salts such as calcium phosphate, calcium sulfate, calcium nitrate and calcium chloride; Magnesium salts such as magnesium nitrate, magnesium chloride, magnesium sulfate, and magnesium phosphate, ferrous nitrate, ferric nitrate, ferrous phosphate, ferric phosphate, ferrous sulfate, ferric sulfate, and hydrochloric acid Examples thereof include iron salts such as ferrous iron and ferric hydrochloride, and double salts thereof, or a combination of two or more thereof.

The particle size of the coated fertilizer of the present invention is not particularly limited, but is preferably 0.5 to 10 mm, more preferably 1 to 10 mm.
６6 mm. The amount of the coating on the fertilizer component is usually 3 to
It is 30% by weight, preferably 4 to 20% by weight.

The coated fertilizer of the present invention can be produced by treating a coated fertilizer obtained by a conventionally known production method with silica or a surfactant. As a method of treating silica or a surfactant, a method of adding silica or a surfactant to a coated, fertilized fertilizer in a stirring, jetting or rolling state is recommended. The method of adding may be as it is, but may be added by dissolving or dispersing in a solvent or the like. When a solvent is used, it is carried out under conditions that allow it to evaporate. The temperature condition for the adhesion is not particularly limited, but is usually 20 to 100 ° C. The time for the treatment is not particularly limited, but is usually 1 to 200 minutes, preferably 2 to 60 minutes.

Specifically, in a 30 ° C. atmosphere, the coated fertilizer is put into a suitable rotating device such as a concrete mixer and rotated at a constant speed to bring the coated fertilizer into a rolling state. To this, a predetermined amount of silica or a surfactant is added, or it is added uniformly over a certain period of time by a method such as spraying so that the whole is uniformly mixed. By continuing the tumbling for a predetermined period of time, a target surface-treated with silica or a surfactant can be obtained.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described with reference to examples. The tests in the examples and comparative examples were performed by the following methods. In the examples, "part" and "%"
Is based on weight. (Dissolution test) 10 parts of the coated fertilizer was immersed in 200 parts of deionized water and stored in a constant temperature bath at 25 ° C. The fertilizer components eluted in water at predetermined time intervals were measured for the concentration of each fertilizer component using a total agricultural soil analyzer ZA-II. Urea was measured using a colorimetric method. The elution rate is expressed as a percentage of the component eluted with respect to the fertilizer component contained in the original coated fertilizer.

(Strength test) Using a backpack type power spreader (Maruyama Seisakusho, MDJ60GTS-26), the coated fertilizer was sprayed under the conditions of engine throttle: 4, shutter opening: 7, and discharged from the tip of the injection pipe. The incoming coated fertilizer was collected. The collected coated fertilizer is subjected to a dissolution test in comparison with that before being applied to a sprayer, and the difference in the dissolution rate (expressed by ΔA) on the 10th day of dissolution is used as a measure of strength. The smaller the value of ΔA, the higher the strength.

(Decomposition Test-1 Photodecomposition Test) A hole was made in the coated fertilizer with a needle, and this was immersed in water to dissolve the fertilizer inside. The coating thus obtained retains almost the original shape of the coated fertilizer. The coating was placed under natural sunlight conditions and the strength after 3 years was evaluated by finger touch. The ranking of the evaluation is as follows. Rank 1: Hardly broken even when rubbed with finger Rank 2: Degree of fragmentation when rubbed hard Rank 3: Shattered when rubbed hard Rank 4: Shattered when rubbed lightly with finger Rank 5: Already before rubbing Shattered or not pickable

(Decomposition Test-2 Biodegradation Test) Two parts of the coated fertilizer was mixed with 500 parts of Fujioka soil (Shizuoka Prefecture), filled in a vinyl pot with a hole, and buried outdoors. 2
After 5 months, the fertilizer was taken out and observed.

(Flotation test) 20 g of coated fertilizer of about 1 gr
After placing in a 0 ml beaker, gently rub the wall of the beaker with 100 gr of deionized water at 20 ° C.
Insert At this time, the number of particles that did not rise with the rise of the water level and remained sinking is expressed as a percentage of the total number. Therefore, the larger the numerical value, the higher the floating prevention effect.

[0036]

Example 1 A jet tower equipped with a spray nozzle and a hot air supply device was used. 30 parts of polyethylene wax having a weight average molecular weight of 850 (trade name: Polyletz 90SZ (manufactured by China Essential Oil Co., Ltd.));
16. Ethylene-vinyl acetate copolymer (trade name: Evaflex 360, manufactured by DuPont-Mitsui Polychemicals, Ltd.)
5 parts by weight, polyethylene containing 2% iron acetylacetonate (trade name: Suntech 2270, manufactured by Asahi Kasei Kogyo Co., Ltd.), 3 parts, sec-alkyl alcohol ethoxylate (trade name: SOFTANOL 70, manufactured by Nippon Shokubai)
A mixture of 0.5 parts by weight and 50 parts of talc (FM-77C manufactured by Fuji Talc Co., Ltd.) was dissolved or dispersed in tetrachloroethylene by heating.

Granular urea (average particle size: 2.9 mm) sieved at 2-4 mm was charged into a jet tower, and the above-mentioned tetrachloroethylene solution was spray-fed under hot air to obtain a coated fertilizer. The ratio of the coating to urea was adjusted to be 11%. The weight of the coated fertilizer was 1.7
× 10 −6 mol / g iron acetylacetonate.

100 parts by weight of the coated fertilizer is put into a rotary mixer and silica dust (EFACO silica union chemical) while rotating at 60 rpm in an atmosphere of 30 ° C.
0.8 parts by weight was added uniformly, and the mixer was kept rotating for 15 minutes. The results of evaluation of the surface-treated coated fertilizer thus obtained were as follows.

Dissolution test: The dissolution rate of nitrogen on day 30 was 3
5.2%, 60.5% on the 60th day, and 89 days until the dissolution rate reached 80% was 89 days. Strength test: ΔA = 5.3% Photodegradation test: Rank 4 Biodegradation test: Holes were observed throughout the coating. Ascent test: 95%

Comparative Example 1 The coated fertilizer that was not treated with silica dust in Example 1 was evaluated. As a result, the result of the floating test was 21%. The other evaluation items did not show a significant difference from Example 1.

Comparative Example 2 A coated fertilizer was prepared in the same manner as in Example 1, except that polyethylene containing no complex was used instead of “polyethylene containing 2% by weight of iron acetylacetonate”. As a result of evaluating this coated fertilizer, the result of the photolysis test was rank 2. No other significant differences were observed with respect to Example 1 for the other evaluation items.

Example 2 Polyethylene wax having a weight average molecular weight of 910 (trade name: Neowax CL, manufactured by Yashara Chemical Co., Ltd.)
40 parts, ethylene-octene copolymer (trade name: Engage 8150, manufactured by Dupont Dow Elastomers) 17 parts by weight, polyethylene containing 2% by weight of iron acetylacetonate (trade name: Suntech 2270 Asahi Chemical Industry Co., Ltd.)
Of talc, 35 parts by weight of talc, 5 parts by weight of starch (manufactured by LM Starch Oji Cornstarch), and 35 parts by weight of talc were dissolved or dispersed in tetrachloroethylene by heating. Granular urea (average particle size: 3.3 mm) sieved at 2.4-4 mm was charged into a jet tower, and a coated fertilizer was obtained in the same manner as in Example 1. The ratio of the coating to urea was adjusted to be 13%.

100 parts by weight of the coated fertilizer is put into a rotary mixer and rotated at 60 rpm in an atmosphere of 30 ° C. while silica dust (EFACO silica union chemical).
0.8 parts by weight was added uniformly, and the mixer was kept rotating for 15 minutes. The results of evaluation of the surface-treated coated fertilizer thus obtained were as follows.

Dissolution test: The dissolution rate on the 30th day was 7.2%,
On the 60th day, 26.5% and 80% elution days showed a so-called S-type elution property of 92 days. Strength test: ΔA = 3.8% Photodegradation test: Rank 4 Biodegradation test: Whitened and holes were observed throughout. Ascent test: 100%

Example 3 Ethylene-vinyl acetate copolymer (trade name: Evaflex 360, manufactured by Du Pont-Mitsui Polychemicals Co., Ltd.) 17
Polyethylene containing 2 parts of iron acetylacetonate and 0.2% of nickel diethyldithiocarbamate (trade name: Suntech 2270, manufactured by Asahi Kasei Corporation)
A mixture consisting of 3 parts, 30 parts of polyethylene (same as above) containing no metal complex, and 50 parts of talc (FM77 manufactured by Fuji Talc Co., Ltd.) was dissolved or dispersed in tetrachloroethylene by heating. Granular phosphoric acid nitrate potassium fertilizer sieved at 2.4-4 mm (grade 15-15-15,
An average particle size of 3.3 mm) was charged into a jet tower, and the above-mentioned tetrachloroethylene solution was spray-fed under a hot air stream to obtain a coated fertilizer. The ratio of the coating to the raw manure was adjusted to be 11%.

Next, 100 parts of the coated fertilizer was again charged into the spout tower to cause a stable jet. Nonionic surfactant polyoxyethylene oleate (Nissan Nonion O
-6 (manufactured by Nippon Yushi Co., Ltd.) was mixed with 50 parts of tetrachloroethylene, and sprayed from the lower part of the jet tower to obtain a coated fertilizer surface-treated with the surfactant.

Dissolution test: As for the dissolution rate of total nitrogen, the dissolution rate on day 30 was 11.3%, the dissolution rate on day 60 was 32.5%, and the 80% dissolution rate was 137 days. Strength test: ΔA = 2.5% Photodegradation test: Rank 4 Biodegradation test: Little change was observed. Ascent test: 98%

[0048]

According to the present invention, in addition to having a high degree of elution controllability, the film also has a property of decomposability by light, preferably biodegradability other than photodegradability.
It is possible to provide a coated fertilizer having practically sufficient strength and excellent anti-floating properties.

Claims (6)

[Claims] Claims: 1. A coating comprising a photolysis catalyst,
A coated fertilizer whose surface is modified with silica and / or a surfactant. 2. The photo-decomposition catalyst comprises iron, cobalt, nickel,
The coated fertilizer according to claim 1, which is a complex of one or more metals selected from zinc and tin. 3. The coated fertilizer according to claim 1, wherein the coating mainly comprises an olefin (co) polymer. 4. The coated fertilizer according to claim 1, wherein the amount of silica is 0.1 to 5% by weight based on the weight of the coated fertilizer. 5. The method according to claim 1, wherein the surfactant is contained in the fertilizer in an amount of 0.01 to 0.01%.
The coated fertilizer according to any one of claims 1 to 4, which is 5% by weight. 6. The coated fertilizer according to claim 3, wherein the olefin (co) polymer is a low molecular weight polyethylene.