WO1999051091A1

WO1999051091A1 - Pulse release pesticide granule having hydrophobic coating film containing silica

Info

Publication number: WO1999051091A1
Application number: PCT/JP1999/001669
Authority: WO
Inventors: Shigeru Tashima
Original assignee: Shionogi & Co., Ltd.
Priority date: 1998-04-07
Filing date: 1999-03-31
Publication date: 1999-10-14
Also published as: AU3054299A

Abstract

A pulse release pesticide granule characterized in that it has at least one hydrophobic coating film layer containing silica. The present pesticide granule allows the control of release rate to an almost constant value without depending on the lag time from the application of the pesticide to the start of release. Therefore, problems such as lowering of expressivity of pesticide effect in using a pulse release pesticide granule can be avoided.

Description

Specification

Pulse-release pesticide granules with silica-containing hydrophobic coating

Technical field

The present invention relates to pulsed pesticide granules.

Background art

When a pesticide formulation is sprayed on a farm or a paddy field in agricultural work, depending on the type of the pesticide or crop or the time of spraying, if the pesticide component starts to be released immediately after spraying, it may cause poor seedling growth or death due to chemical damage. There is fear. In addition, a time-efficient spraying method is required from the viewpoint of work labor and the like. To avoid these problems, the pesticide formulation is not released immediately after the pesticide formulation is sprayed on the field, etc., but is released after a certain period of time (commonly called lag time). There is a demand for the development of a sustained-release formulation that can almost completely release the drug. In this field, this type of pesticide formulation is usually called a pulse-release pesticide formulation or a time-dissolving pesticide formulation. For example, Japanese Patent Application Laid-Open Nos. This is described in, for example, Japanese Patent Application Laid-Open No. 80514/1994 and Japanese Patent Application Laid-Open No. 6-93033.

In conventional pulsed release preparations, generally, the lag time until the active ingredient starts to be released after application is adjusted mainly by the type and mixing ratio of the swelling agent and the coating agent for forming the hydrophobic coating film. However, in this case, the dissolution rate after the release of the active ingredient generally becomes slower with an increase in the lag time, for example, as described in JP-A-6-93003 This tendency is also observed in the pulse-release pesticide preparations and the like. Incidentally, similar results have been reported for pulsed-release pharmaceutical preparations. [1) S. Ueda et al .:!. Drug Targe tting Vol. 235-44 (1994), 2) Suzuki et al. PHARM TECH JAPAN Vol. 9 (9) 7- 16 (1993) etc.].

For this reason, if the lag time is unexpectedly prolonged when a pulse-release pesticide formulation is used in a field, an upland field, a paddy field, or the like, the expected level of drug effect may not be achieved. Therefore, the lag time within the range that can be set normally Therefore, there has been a demand for the development of a pulse-release pesticide formulation that has a substantially constant dissolution rate after release of the pesticide from the formulation and can set the lag time arbitrarily, regardless of the length of the period. However, no such pesticide formulation has been known.

JP-A-9-268103 discloses a pulse-release type coated pesticide granule containing an inorganic powder in the film. Only talc and clay are actually used as the inorganic powder. No control has been considered for controlling the dissolution rate after the release of pesticides.

Also, Japanese Patent Application Laid-Open No. 9-1315902 describes a granule containing anhydrous silicic acid, but the preparation is not particularly intended for pulse release, and the purpose of adding silica is Indicates prevention of unity during storage and suppression of dusting during use, and is not directly related to the release and solubility of pesticides.

Disclosure of the invention

In view of the above problems, the inventors of the present invention have conducted intensive studies. As a result, if a relatively small amount of silica is contained in a hydrophobic coating film in a pulse-release pesticide granule, the drug can be released regardless of the lag time. It has been found that the subsequent elution rate can be kept almost constant and the lag time can be set arbitrarily, and the present invention exemplified below has been completed.

(1) A pulse-release pesticide granule (hereinafter, also referred to as “granule”), characterized by having at least one hydrophobic coating film containing silica.

(2) The granule according to the above (1), which has one or two layers of the hydrophobic coating film.

(3) The granule according to the above (1), wherein the silica is hydrated silica.

(4) The granule according to the above (1), wherein the silica has an average particle diameter of about 0.5 to 20.

(5) The granule according to (1), wherein the amount of silica is about 0.05 to 7.5% by weight based on the total weight of the granule.

(6) The granule according to the above (1), wherein the compounding amount of silica is about 0.5 to 75% by weight based on the total weight of the coating agent for forming the hydrophobic coating film.

(7) The granule according to the above (1), wherein the coating agent for forming the hydrophobic coating film is a hydrophobic polymer.

(8) The hydrophobic polymer is an orefin polymer, an orefin copolymer, or a vinylidyl chloride. One or more polymers selected from the group consisting of den-based copolymers, gen-based copolymers, acrylic-based copolymers, ether polymers, polyvinyl-based compounds, cellulose-based compounds, and waxes The granule according to the above (7).

(9) The granule according to the above (7), wherein the hydrophobic polymer is an olefin polymer, an acrylic copolymer, or an ether polymer.

(10) The dissolution rate after the release of the pesticide is controlled to be within a substantially constant range without being affected by the period (lag time) until the release of the pesticide contained after application. (9) The granule according to any one of (1) to (4).

(11) The granule according to (10), wherein the lag time is about 3 to 40 days.

(12) The granule according to the above (10) or (11), wherein the dissolution rate is a dissolution rate until the dissolution rate reaches 80%.

(13) The above (10) to (10), wherein the range of the elution rate is about 1 to 5% of the day (at 20).

The granule according to any one of (1 2).

(14) The granule according to any of (10) to (12), wherein the range of the dissolution rate is about 2 to 3% (at 20).

(15) The granule according to any one of the above (1) to (14), wherein the pesticide content is metminostrobin.

(16) The pulse according to any one of the above (1) to (15), comprising a step of coating the mixture containing the pesticide and the swelling agent at least once with a hydrophobic coating film containing silica. Method for producing release pesticide granules. Examples of the pesticides contained in the present granules include pesticidally active ingredients such as herbicides, insecticides, and fungicides, and are preferably components in which the granules are less likely to aggregate during granule preparation. These can be used alone or in combination. Specific examples are shown below.

[Herbicide] 4- (2,4-dichlorobenzoyl) -1,3-dimethyl-5-pyrazolyl-p-toluenesulfonate (generic name: pyrazolate), 1- (α, α-dimethylpentyl) 3- (paratolyl) urea (generic name: Daimron), (RS) -2-bromo-Ν-(,-dimethylpentyl) -3,3-dimethylbutylamide (generic name: bromobutide), 2- (1,3-Benzothiazo-1-yl-2-yloxy) -1-N-methylacetanilide (generic name: mefenacet), MCP, MCPB, triclopyr, nabroanilide, CNP, chrometoxinil, biphenox, MC C, Pyripiccalp, DCPA, promobutide, mefenacet, nablobamide, diphenamide, pilopizamide, asylum, DCMU, linuron, dimelon, methyldimuron, tebuchu, bensulfuron-methyl, simazine, atrazine, simetrin, ametrin, ametrine , Promethrin, Dimetamethrin, Metribudine, Bentazin, Oxaziazone, Pyrazolate, Benzophenap, Pylogisamine, Glyphosate, Vialaphos, Aroxydim, Imazosulfuron, Azimsulfuron, Birazosulfuronethyl, Shinosulfuron.

[Insecticide] (2-Isopropyl-4-methylpyrimidyl-1-6) -getylthiophosphate (generic name: diazinon), 1,3-bis (potumbamoylthio) 1-2— (N, N-dimethylamino) propane hydrochloride (generic name: Cartap), 0,0-dimethyl-0.1- [3-methyl-4-1 (methylthio) phenyl] thiophosphate (generic name: MPP), 0,0-Jethyl-0- (5-phenyl-2-isoxazolyl) phospho Rotioate (generic name: isoxathion), pyridafenthion, dimethyl, PMP, C VMP, dimethylvinphos, acephate, salicion, DEP, NAC, MTMC, MIPC, PHC, MPMC, XMC, vendiocalp, pyrimicarb , Mesomyl, Oxamil, Thiodicalp, Cypermethrin, Cartap hydrochloride, Thiocyclam, Surutappu, difluoromethyl base Nzuron, Tefurupenzuron, Kurorufu Ruazuron, buprofezin, to Kishichiazokusu, oxidation Fenbu evening tin, pyrid Ben, black Fuente gin, two Tenbiramu.

[Disinfectant] 3-aryloxy-1,2-benzisothiazole-1,1-dioxide (generic name: probenazole), diisopropyl 1,3-dithiolan-1_2_ylidene-malonate (generic name: isoprothiolane), 1,2,5,6-tetrahydropyrro [3,2,1-ij] quinoline-1-one (generic name: pyroquinone),, α-trifluoro-1-3-isopropoxy-1 0—toluanilide (generic name: Flutranil), (£) -2-Methoxyimino-JV-methyl-2- (2-phenoxyphenyl) acetamide (generic name: meth) Minos trobin), ziram, thiuram, kiabutane, TPN, fusaride, tolclofosmethyl, josetil, thiophanetomethyl, benomyl, carbene zool, thiabene zosol, dietofencalp, iplodione, vinclozolin, procymidone, fluomidone , Oxycarboxin, Mepronil, Flutolanil, Pencyclon, Metalaxyl, Oxazixyl, Triadimefon, Hexaconazole, Triforin, Blastosidine S, Kasugamycin, Polyoxin, Validamycin A, Mildiomycin, PCNB, Hydroxyisoxazol, Dazomet, Dimethylimole, Diclomedin, Triazine, Phelimsone, Probenazole, Isoprothiolane, Tricyclazole, Pyroquilon, Oki Examples include Solinick and the like, and preferably Metominostrobin.

The content of the pesticide is usually about 0.5 to 20% by weight, preferably about 0.75 to 18% by weight, more preferably about 1 to 15% by weight, based on the total weight of the granules.

In the present granule, the number of layers of the hydrophobic coating film is one or more. For example, two layers may be used, but one layer is preferable in terms of preparation efficiency, cost and the like. If the granule has multiple coating layers, the pesticide may be present in the center of the granule, between the coating layers and / or on the granule surface. By including multiple pesticides in such granules, it is also possible to adjust the lag time and dissolution rate for each pesticide. The coating film is usually coated on the surface of a granular mixture containing a pesticide and, if desired, a swelling agent, a carrier, and the like.When coating two or more layers, the first coating layer counted from the center of the granule May be sequentially coated on the outside.

The coating agent for preparing the hydrophobic coating film is not particularly limited as long as it is a coating agent capable of imparting a pulse release property, but is preferably a hydrophobic polymer having low water permeability, such as polypropylene or polybutene. And polyolefins such as polyvinylidene chloride, polystyrene and low-density polyethylene; ethylene-carbon monoxide copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, ethylene-propylene copolymer, ethylene- Orefin-based copolymers whose main component is an orefin such as vinyl acetate-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid copolymer; vinylidene chloride-vinyl chloride copolymer Vinylidene chloride copolymer; Gen-based copolymers such as prene polymer, butadiene polymer, butadiene-styrene copolymer, styrene-isoprene copolymer; acryl-based polymers such as ethyl acrylate / methyl methacrylate copolymer and methacrylic acid copolymer Copolymers; Ether polymers such as epoxy resins; Polyvinyl compounds such as polyvinyl acetate, vinyl acetate copolymers, polyvinyl alcohol; Cellulosic compounds such as ethyl cellulose; Waxes such as beeswax and paraffin Etc. are exemplified. Among them, particularly preferred covering agents are an olefin polymer (eg, polyvinylidene chloride, etc.), an acrylic copolymer (eg, ethyl acrylate / methyl methacrylate copolymer, etc.), an ether polymer (eg, epoxy) Resin, etc.).

In order to form a coating film of these hydrophobic polymers, they may be used alone or in combination, dissolved or suspended in water or an organic solvent, and sprayed.If necessary, a filler such as talc is added. You may keep it.

The amount of the coating agent is about 5 to 30% by weight, preferably about 7.5 to 20% by weight, more preferably about 10 to 15% by weight, based on the total weight of the granules. If the compounding amount is too large, the lag time from the application of the granules to the release of the pesticide becomes too long, and the timing of the onset of the medicinal effect is missed. In addition, the effect of the present invention, that is, the control of the dissolution of pesticides by the addition of silicide, may not be sufficiently achieved, and as a result, the dissolution rate may be reduced due to the extension of lag time. On the other hand, if the amount of the hydrophobic coating film is too small, the lag time becomes too short, which adversely affects the growth of the seedlings or releases the pesticides before the desired onset of efficacy. There is a risk that the expected effect may not be obtained.

The silica (silicon dioxide) contained in the hydrophobic coating layer may be either anhydrous or hydrous, but is preferably hydrophilic silica. Examples of hydrophilic hydrated silica include Carplex # 80, # 80—D, # 67, # 1120, # 110 (Shionogi), Aerozil 200 (Nippon Aerozil), and Toksir N , GUN, P (Tokuyama), Nibsil NS, NSK (Nippon Silica Industry) and the like. The average particle diameter of the sily force is preferably about 0.5 to 20 m, and more preferably about 1 to 10 m. If the particle size is too large, it will not be completed in the hydrophobic coating. The spray in the granulator, which does not completely bury and coats the hydrophobic polymer, may be clogged.

In this granule, the lag time of the pesticide component can be adjusted and the dissolution rate can be controlled by appropriately adjusting the amount of silica. One example is that by slightly adjusting the amount of silicic acid added, the dissolution rate of the pesticide can be substantially reduced within the lag time that can be set for pulse-release pesticide granules, regardless of their length. It is also possible to keep it within a certain range. In other words, in the design of conventional pulse-release pesticide granules, in order to adjust the lag time and dissolution rate, there were cases where the type and amount of disintegrants and coating agents had to be drastically changed. The use of this granule makes it easy to fine-tune the dissolution pattern. Of course, it is also possible to adjust the lag time and dissolution rate by appropriately changing the type and amount of additives other than silica, etc., and granules designed in that way are also included in the present invention.

The amount of silica varies depending on the type and amount of the pesticide, hydrophobic coating film, swelling agent, etc. contained, or the target lag time and elution rate of the pesticide, etc., and cannot be specified unconditionally. It is usually about 0.05 to 7.5% by weight, preferably about 0.1 to 5% by weight, and more preferably about 0.25 to 1% by weight. It is usually about 0.5 to 75% by weight, preferably about 1 to 50% by weight, more preferably about 2.5 to 10% by weight, based on the total weight of the hydrophobic coating agent. If the amount of silica is too large, the lag time may be too short and the pesticide may be released earlier than the desired time. In addition, the elution rate may be so high that the expected efficacy may not be obtained. On the other hand, if the amount of silica is too small, the dissolution control of the pesticide becomes insufficient, and as a result, the dissolution rate decreases due to the extension of the lag time, or the lag time becomes too long and the desired time is reached. Pesticides may not be released in the future.

The lag time generally means the period from the date and time when the granule is sprayed until the pesticide content starts to be released from the inside of the granule, but in this specification, for the sake of convenience, the pesticide content is used for the dissolution test. The time required to elute about 1% in water is called lag time. In the present granule, the period of the lag time during which the dissolution rate of the contained pesticide can be controlled is usually about 3 to 40 days, preferably about 5 to 30 days. The method for measuring the dissolution rate is as follows: The dissolution test method for pesticides described in J. Pesticide Science Vol.21 404-411 (1996) etc. may be followed, and as a guide, for example, after the start of dissolution, the dissolution rate becomes about 80% to 90%. The elution rate may be calculated based on the time required to reach the elution rate. In this granule, if the dissolution rate of the pesticide after the lag time elapses is defined by the amount of elution per day based on the pesticide content in the granule, for example, about 1 to 5% day (at 20), Preferably it can be controlled in the range of about 2-3% / day (at 20).

The granules optionally contain various bases and additives for pesticide preparations (eg, swelling agents, carriers, binders, surfactants, etc.) which can be generally used for preparing pulse-release granules. Get. An example is shown below.

(Swelling agent) A substance that expands its volume by absorbing water, thereby releasing pesticides inside the granules. Normally, the swelling agent is mixed with a pesticide as a coating granulation method and adheres to the surface of a carrier such as granular silica sand or granular calcium carbonate, or adheres the pesticide to the carrier surface and then adheres to the surface Let it. In addition, as an extrusion granulation method, a carrier, an agricultural chemical, etc. and a swelling agent are mixed together and molded by the extrusion granulation method. Adhere. Specific examples include bentonite, starch, water-absorbing polymers, and the like. As the bentonite, a sodium bentonite is preferable. Examples of the starch include corn starch, potato starch, methyl starch, carboxymethyl starch and the like. Examples of the water-absorbing polymer include cellulosic polymers, polyvinyl alcohol, sodium polyacrylate, cross-linked polyacrylate, starch-polyacrylate, isobutylene-maleate, PVA-polyacrylate and the like. You. Preferably, the swelling agent is bentonite or a water-absorbing polymer (in particular, sodium polyacrylate, crosslinked polyacrylate, starch-polyacrylate, isobutylene monomaleate, PVA-polyacrylate). is there. These swelling agents can be used alone or in combination, and their types and combinations are not particularly limited. The amount of the swelling agent is usually about 0.1 to 20% by weight, preferably about 1 to 16% by weight, more preferably about 2 to 12% by weight based on the total weight of the preparation. If the amount of the swelling agent is too large, the lag time becomes too short or the dissolution rate becomes high. May be too much On the other hand, if the amount is too small, the lag time may be too long or the pesticide may not be released even when sprayed.

(Carrier) A chemically inert particulate substance that can adhere a pesticide, swelling agent, etc. to its surface, or a chemically inert powdery substance that can be mixed with a pesticide, swelling agent, etc. , Diatomaceous earth, clay, bentonite, talc, kaolin, carbonated silica, silica sand and the like, and granular and powdery carriers generally used in the preparation of pulsed release granules. Carriers are preferably silica sand, calcium carbonate, bentonite, talc and clay.

The granular carrier may be either a crushed product (eg, granular calcium carbonate, granular silica sand, etc.) or a granulated product, but the shape is spherical and the particle size is 0.1 to 3 MK, preferably 0.5 to 2.5 mm. It is desirable to use granular materials. Further, the powdery carrier is desirably a powdery one having an average particle diameter of l to 20 im. The amount of the carrier is usually about 30 to 90% by weight, preferably about 40 to 85% by weight, more preferably about 50 to 80% by weight, based on the total weight of the preparation.

(Binder) A powder carrier, an active ingredient, a swelling agent, etc., which is used to adhere the active ingredient, swelling agent, etc. to the surface of the granular carrier, is mixed, and the granules are formed by extrusion granulation. It is used for the purpose of admixing powdered carriers and active ingredients, and for the purpose of adhering a swelling agent etc. to granules formed by extrusion granulation, showing adhesiveness when dissolved It is a polymer.

Preferably, it is a polymer that is soluble in both water and an organic solvent. Specifically, hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyvinyl pyrrolidone, polyethylene glycol, epoxy resin, or the following surfactant And the like. These binders can be used alone or in combination. In addition, their types, combinations, and contents may be set as appropriate.

(Surfactant) A substance that is added to the coating together with silica to adjust the lag time and dissolution rate, and is also used as a binder. Non-ionic and anionic evenings can be used. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene ether, and polyoxyethylene alkyl ether. Sterol, sorbitan fatty acid ester, ethylene oxide Z-propylene oxide copolymer, and higher fatty acid alkanolamide are used. Examples of the anionic surfactant include a metal salt of a polymerized condensate of naphthalene sulfonic acid, an alkenyl sulfonate, a formalin condensate of a naphthalene sulfonate, an alkyl naphthalene sulfonate, a lignin sulfonate, and an alkyl Aryl sulfonate, alkylaryl sulfonate sulfate, polystyrene sulfonate, polycarboxylate, polyoxyethylene distyryl phenyl ether sulfate ammonium, higher alcohol sulfonate, higher alcohol ether sulfonate, dialkyl Sulfosuccinate, higher fatty acid alkali metal salts and the like are used. Preferred are sorbitan fatty acid ester, lignin sulfonate and polycarboxylate. The amount is usually about 1 to 10% by weight, preferably about 2 to 8% by weight, more preferably about 3 to 6% by weight, based on the total weight of the preparation.

The production of the present granules may be basically carried out in accordance with conventional pulse-release granules, and is not particularly limited, but is preferably as follows. First, a granule is prepared with a pesticide and, if necessary, a swelling agent, a carrier, a binder, a surfactant and the like. Next, a silica-containing coating agent is coated on the surface with a fluidized-bed granulator, pan coating device, rolling coating device, rolling fluid type coating device, ventilation type coating device, Nauter mixer, etc. A hydrophobic coating film is provided by coating with a coating. The coating film may be coated a plurality of times as needed. Representative preparation methods are shown below.

(Preparation of one-layer coated granules by coating granulation method)

After the solvent in which the binder is dissolved is stirred and dropped on the carrier, a mixture of a pesticide, a swelling agent and, if desired, other compounding agents (eg, talc, clay, etc.) is adhered to the surface of the carrier, and granules are formed. Get. Next, the present granules are obtained by spraying a water-based emulsion solution of the coating agent or a coating solution in which the sily power is suspended in an organic solvent in which the coating agent is dissolved, onto the surface of the granules. The concentration of the coating agent in the coating solution is about 0.5 to 20% by weight, preferably about 1 to 15% by weight, more preferably about 2 to 10% by weight. Also, the concentration of silica is about 0.5 to 50% by weight, preferably about 1 to 30% by weight, more preferably about 2 to 25% by weight. Talc, clay, etc. mixed with pesticides and swelling agents The lag time can also be slightly adjusted by adjusting the amount of the compound.

(Preparation of two-layer coated granules by coating granulation method)

After the solvent in which the binder is dissolved is dropped on the carrier with stirring, the pesticide is attached to the surface of the carrier. After the solvent in which the binder is dissolved is again dropped with stirring, a swelling agent is adhered to the surroundings to obtain granules. Next, a coating solution in which silica is suspended in an organic solvent in which the coating agent is dissolved is sprayed on the surface of the granule (primary coating). Further, the aqueous granulation solution of the coating agent or a coating solution in which silica is suspended in an organic solvent in which the coating agent is dissolved is sprayed (secondarily coated) on the surface of the primary coating film, whereby the granules of the present invention are obtained. Get. In this case, the concentration range of each component in the coating solution is almost the same as in the case of preparing the above-mentioned one-layer coated granule.

(Preparation of one-layer coated granules by extrusion granulation method)

After mixing pesticides, powdery carriers, swelling agents, binders, surfactants, etc., they are kneaded with water. The mixture is extruded and granulated, and then sized to obtain a granule. In some cases, a swelling agent may be attached to the granules. Next, the present granule is obtained by spraying a water-based emulsion solution in which the coating agent is suspended or a coating solution in which silica is suspended in an organic solvent in which the coating agent is dissolved, on the surface of the granule. In this case, the concentration range of each component in the coating liquid is almost the same as in the case of preparing the above-mentioned coated granules.

In the above preparation, the amounts of other components such as pesticides and swelling agents may be appropriately set in consideration of the kind of the pesticide contained, the intended dissolution rate, the timing of application, and the like. One example is shown below.

(1) When the dissolution rate after pesticide release is about 1 to 5% days (at 20):

Pesticides: Swelling agent: Coating agent: Silica = 1: 0.33 to 5.33: 1.67 to 5: 0.0 to 0.5

(2) When the dissolution rate after pesticide release is about 2-3% days (at 20):

Pesticides: Swelling agent: Coating agent: Silica = 1: 0.67 to 2.67: 3.33-5: 0.17 to 0.33

When this granule is used in paddy fields and fields, the amount of application varies depending on the amount of pesticide contained and cannot be specified unconditionally, but is usually about 0.6 to 2 kg / 10 a. In the nursery box If used, the application rate is about 30-100 g. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a graph showing the dissolution of the granule (single-coated type).

Figure 2 is a graph showing the dissolution of the granule (two-layer coating type). BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, examples of the present invention will be described.

Example 1 (two-layer coated granules by coating granulation method)

Hydroxypropylcellulose (0.6 g of HPC-SU dissolved in ethanol, 12D1L) was added dropwise to 240 g of granular silica sand (8.6 to 20 mesh) with stirring, and 9.3 g of methaminostrobin was added to the granular silica sand. To this granule, 42 mL of an ethanol solution of 2.1 g of HPC-SL was added dropwise with stirring, and then 24.0 g of a swelling agent (starch / polyacrylate) was attached. Next, a coating solution in which 0.9 g of Carplex # 80 (Shionogi) was suspended in 180 inL of a ethanol solution containing 9 g of ethyl cellulose was sprayed onto the surface of the granule (primary coating). In addition, a coating solution in which 2.1 g of Carplex # 80 (Shionogi) was suspended in 420 g of an aqueous emulsion solution of vinylidene chloride (solid content: 5%) was applied to the surface of the primary coating film. A secondary coating film is formed by spraying Scan-release granules (PU- 13) (Yield: 290 g, size distribution:.. 0 8 4~ 2 3 6 mm). To afford Example 2 (more coated granules according Koti ring granulation method)

Hydroxypropylcellulose (HPC-S), 50 mL of an ethanol solution in which 2.5 g was dissolved was added dropwise to 240 g of granular silica sand (8.6 to 20 mesh) with stirring, and 9.3 g of methinostrobin, a swelling agent (starch / polystyrene) A mixture of 24 g of acrylate and 24 g of talc was applied to the surface of the granule, and then 3.0 g of Carplex # 80 was suspended in 600 g of an aqueous emulsion solution of vinylidene chloride (solid content: 5%). The coating solution thus obtained was sprayed onto the surface of the granules to obtain the pulse-releasing granules (Ρϋ-120) of the present invention (yield 298). g). Another granule (PU-121) was obtained in the same manner except that the amount of Carplex # 80 was 1.5 g (yield 296 g, particle size distribution: 0.84 to 2.36 mm). . Example 3 (Single-coated granules by coating granulation method)

Hydroxypropylcellulose (HPC-SL) 2.5 g dissolved ethanol solution 50 mL was dropped into 210 g granular silica sand (8.6 to 20 mesh) with stirring, then 9.3 g Metominostrobin, swelling agent (starch poly) A mixture of 12 g of acrylate and 24 g of talc was applied to the surface of the granules. Next, a coating solution, in which 2.63 g of talc and 1.5 g of Carplex # 80 were suspended in 525 g of an aqueous emulsion solution of vinylidene chloride (solid content: 5%), was sprayed on the surface of the granules. Thus, a pulse release granule (PU-201) of the present invention was obtained (yield: 297 g, particle size distribution: 0.84 to 2.36 mm). Example 4 (Single-coated granules by extrusion granulation)

45.5 g of methinostrobin, 90.0 g of bentonite having water swellability, and 103 g of clay were uniformly mixed with a kneader and kneaded with water. This mixture was extruded and granulated by a screw extrusion type granulator (screen diameter: 0.8 mm diameter), and then sized by a spherical granulator (Marmelizer 1) to obtain a granulated product. Then, 50 mL of an ethanol solution in which 2.5 g of hydroxypropylcellulose (HPC-SL) was dissolved was added dropwise to 238.5 g of the granulated material (8.6 to 20 mesh) with stirring, and then swelled on the surface of the granulated material. 24 g of agent (starch // polyacrylate) were applied. Next, a coating solution in which 3.0 g of talc and 2.25 g of Carplex # 80 were suspended in 600 g of an aqueous emulsion solution of vinylidene chloride (solid content: 5%) was sprayed on the surface of the granules. Thus, a pulse-releasing granule (PU-203) of the present invention was obtained (particle size distribution: 0.7 to 1.8 mm). Test example (Measurement of dissolution rate)

200 mg of the pulse-eluting granules prepared in the examples were put into a 300 mL beaker containing 300 mL of 3rd hard water, and stored in a thermostat at 20. After stirring the sample solution in the beaker 20 times with a spatula 20 times at a speed of Z minutes, collect 2 mL of the sample solution, The concentration of methinostrobin in the collected solution was quantified by HPLC. Next, 148 mL of the sample solution in the beaker was discarded, and 150 mL of third-degree hard water not containing a methinosto mouth bottle was newly added, and the mixture was put into the thermostat again. The results are shown in FIGS.

(Figure 1: Granules of Example 1)

The lag time was about 7 days. Next, the regression equation after the start of dissolution was calculated from the measured dissolution rate for 48 days when the dissolution rate reached approximately 90%. Y = 2.425 X—24.502, r = 0.9960 (X: days, Y: dissolution rate ( %), R: correlation coefficient). Thus, a linear relationship was observed between the number of days and the dissolution rate, and it was confirmed that the dissolution rate was almost constant without decreasing.

(Figure 2: Granules of Example 2)

By adjusting the amount of silica added and comparing the dissolution properties when the lag time was about 12 days (Ρϋ-120) and about 23 days (PU-121), the lag time for both granules was It showed a similar elution tendency. The regression equation after the start of dissolution was calculated based on the measured values until the dissolution rate reached about 80% .As shown below, the dissolution rate of the pesticide contained in both granules was about 2-3% days. (At 20), there was no significant difference. (PU-120) Υ = 3.0208 X-23.812, r = 0.9898

(PU-121) Y = 2.0302 X-46.542, r = 0.9898 Industrial applicability

With this granule, the lag time until the release of the pesticide can be easily and arbitrarily set in accordance with the desired onset of the drug effect, and the dissolution rate after release can be controlled within a substantially constant range. Therefore, for example, when a pesticide formulation is applied to a nursery box, no phytotoxicity occurs during the seedling stage of rice, which is susceptible to pesticides, and a sufficient amount of pesticide is required when the desired insecticidal, sterilizing, and weeding effects are required It is possible to reduce the labor for spraying pesticides and to reduce the amount of sprayed chemicals. This granule can be used in nursery boxes, paddy fields or uplands.

Claims

The scope of the claims

I. A pulse-release pesticide granule characterized by having at least one hydrophobic coating film containing a sily power.

δ 2. The granule according to claim 1, having one or two layers of the hydrophobic coating film.

3. The granule according to claim 1, wherein the silica is hydrated silica.

4. The granule according to claim 1, wherein the silica has an average particle size of about 0.5 to 20 m.

5. The granule according to claim 1, wherein the amount of the sili force is about 0.05 to 7.5% by weight based on the total weight of the granule.

0 6. The granule according to claim 1, wherein the blending amount of the sily force is about 0.5 to 75% by weight based on the total weight of the coating agent for forming the hydrophobic coating film.

7. The granule according to claim 1, wherein the coating agent for forming a hydrophobic coating film is a hydrophobic polymer.

8. The hydrophobic polymer is an orefin polymer, an orefin-based copolymer, a vinylidene chloride-based copolymer, a gen-based copolymer, an acrylic-based copolymer, a polyvinyl-based compound, a 5-cellulose-based compound, and The granule according to claim 7, wherein the granule is one or more polymers selected from the group consisting of waxes.

9. The granule according to claim 7, wherein the hydrophobic polymer is an olefin polymer, an acrylic copolymer, or an ether polymer.

10. The dissolution rate after release of the pesticide is controlled to be within a substantially constant range without being affected by the period (lag time) until the pesticide is released after application.

9. The granule according to any one of 9 above.

The granule according to claim 10, wherein the lag time is about 3 to 40 days.

12. The granule according to claim 10, wherein the dissolution rate is a dissolution rate until the dissolution rate reaches 80%.

5 13. The granule according to any of claims 10 to 12, wherein said dissolution rate ranges from about 1 to 5% days (at 20).

14. A granule according to any of claims 10 to 12, wherein the range of said dissolution rate is about 2-3% days (at 20).

15. The granule according to any one of claims 1 to 14, wherein the contained pesticide is metminostrobin.

The pulse release according to any one of claims 1 to 15, comprising a step of coating the mixture containing the pesticide and the swelling agent at least once with a hydrophobic coating film containing silica. Method for producing pesticide granules.