WO2004095925A1

WO2004095925A1 - Process for the preparation of a pesticidal formulation

Info

Publication number: WO2004095925A1
Application number: PCT/EP2004/004571
Authority: WO
Inventors: Atsushi Tomioka; Hiroshi Hasegawa; Takahiro Matsubara
Original assignee: Syngenta Participations Ag
Priority date: 2003-04-30
Filing date: 2004-04-29
Publication date: 2004-11-11
Also published as: JP2006524661A; KR20060015549A; JP4782669B2; KR101083242B1; TW200503616A; MY147740A; CN1756483A; JP2011126903A; CN100405905C

Abstract

A process for the preparation of a pesticidal formulation comprising the steps of (a) mixing at least one surfactant with at least one oily substance (b) coating Kaga Balloon particles with the mixture obtained in step (a) in a mixer (c) adhering at least one pesticidal active ingredient and optionally at least one carrier to the coated Kaga Balloon particles obtained in step (b).

Description

Process for the preparation of a pesticidal formulation

The instant invention relates to a new process for preparation of a pesticidal formulation with high active ingredient content which diffuses rapidly over the surface of water, efficiently releasing pesticidal active ingredients throughout the water surface, thereby saving labor load of growers, storage volume during distribution as well as production costs thereof to a large extent.

Due to the water filling of paddy fields, it is not easy to apply pesticides in such a manner that they are scattered uniformly over the surface of water. As a result, if a grower desires to uniformly apply pesticides, it is in principle necessary for him/her to enter the paddy field and scatter pesticides changing the position from which the grower applies pesticides, demanding lots of works. Driven by the motivation to reduce labor load of growers, the so-called pack formulations have drawn attention among pesticide manufacturers. The pack formulations with some exceptions have three aspects in common: (1) they float, (2) diffuse and (3) release pesticidal active ingredients on the surface of, or into, the water. So far various types and various production methods of pack formulations comprising a solid carrier having a specific gravity of less than one and a solid pesticidal active ingredient have been proposed (see, for example in JP Kokai Hei Nos. 5-155703 and 9-183701).

In general, it is of substantial importance to increase the amounts of active ingredients in pack formulations since it enables the reduction in amounts of formulations to be applied, thereby reducing the labor load of growers, the storage volume during distribution as well as the production costs thereof.

Another prerequisite for a successful pack formulation is a satisfactorily large diffusibility, which together with the sufficient active ingredient content contributes to the above effects. Without sufficient diffusibility, the amount of application cannot be reduced, eventually leading to the necessity in large storage amounts and high production costs. Therefore, a sufficiently high active ingredient content and a satisfactorily large diffusibility are the most important factors for the production of advantageous pack formulations. Pack formulations are generally finished in such a manner that they are packed in water-soluble bags made of water-soluble polymers e.g. polyvinylalcohol, which are directly applied to the surface of water. After the bags have dissolved in the water, particles of the pack formulation spread over the surface of water releasing active ingredients.

Among the pack formulations so far proposed, the pack formulations as disclosed in JP Kokai Hei Nos. 5-155703 and 9-183701 have preferable characteristics from the viewpoint of ease in production. Said formulations are produced by coating a solid carrier having a specific gravity of less than one with an oily substance, followed by adhesion of a solid surfactant and a solid pesticidal active ingredient thereto. However, the active ingredient contents in these formulations are usually as low as 10%, at the highest 18%, by weight, leading to their fatal drawback that they have to be applied in large amounts, thereby not reducing the labor load of growers, the storage volume during distribution as well as the production costs thereof.

It has now been surprisingly found that a formulation, wherein particles of at least one solid pesticidal active ingredient is adhered to the surface of Kaga Balloon particles which are coated with a mixture comprising at least one surfactant and at least one oily substance, unexpectedly allows active ingredient contents as high as 50% by weight quite easily and exhibits extraordinarily high- and uniform diffusibility, whilst the process for the production thereof is extraordinarily simple. Said formulation is therefore an object of the instant invention.

Kaga Balloon is an artificially modified natural pumice produced by KAGALITE KOGYO Co., LTD., Japan. The "Kaga" of Kaga Balloon is an ancient name of the district around Kanazawa where said natural pumice is obtained, now called "Ishikawa Prefecture" facing the Japan Sea. It is still not known why Kaga Balloon allows the achievement of the instant invention. However, natural pumice can have different elements, different components, different crystal structure, different pore ratios etc. depending upon when and where it has been created. It is reasonably assumed that the combination of all of these factors embodying in Kaga Balloon effects the achievement of the instant invention. For the production of Kaga Balloon, particles of the above natural pumice having particle diameters of 300-2500μm are used. Kaga Balloon is produced by instantaneous heat treatment of said particles at a temperature of 900-1000°C, preferably 930-980°C, in a fluidized bed type infurnace to thereby foam them. Usually, silica sand is placed inside the furnace in order to achieve uniform temperature distribution. The time during which the above natural pumice is heat treated is not longer than 10 seconds, usually 3-5 seconds. The foamed particles thus prepared are subject to sieving and, thereby obtaining Kaga Balloon.

Kaga Balloon has a bulk density of less than 1 , preferably 0.1-0.8, more preferably 0.1-0.5. Its floatability, i.e. the ratio of particles floating on the surface or in the water, is not less than 50%, preferably not less than 70%, more preferably not less than 85%. It absorbs oily substances in amounts of not less than 5%. Particle size distribution of Kaga Balloon is such that 80% by weight of the particles lie within the range of 100-3000μra, preferably 300-2800μm, most preferred 500-2800μm.

Other natural or artificial modified pumice, which demonstrate high pesticidal content (active ingredient content of 20 to 50 %, preferably 25 to 45 %) are in the scope of the instant application.

The above bulk density is determined as follows:

A metallic net, each aperture of which is 3350μm in diameter, is placed exactly 20 cm above the top edge of a metal-made circular receiving container whose diameter is 50mm and volume is 100ml. The sample whose bulk density is to be determined is gradually sieved into the receiving container till the sample forms a cone-like shape over the top edge of the receiving container. Then, the cone-like part is precisely removed and the weight W (g) of the sample remaining in the receiving container is measured. The bulk densities are determined according to the formula: Bulk density = W/100.

The floatability is determined as follows:

S (g), which is about 20.0g, of a sample which has precisely been weighed is charged into a cone-shaped flow meter having a shape like a separating funnel, which is then stirred while gradually adding water till the limit within which the water does not overflow. After 30 minutes, the particles floating are completely removed, and the dry weight C (g) of the precipitated particles is measured. The floatabilities are determined according to the formula: Floatibility (%) = (S-C)/Sx100.

The oil absorption is measured as follows:

S (g), which is about 10g, of a sample which has precisely been weighed is charged into a

Meyer flask equipped with a stopper, to which linseed oil is gradually added so that the oil is focused to the central part of the sample. The flask is then thoroughly shaked. Defining the time at which no more linseed oil is able to be absorbed, namely the time at which the flowability of the sample decreases and the linseed oil starts to adhere to the surface of the sample, as the terminal point, the amount H (g) of the linseed oil used till the terminal point is measured. The oil absorption is determined according to the formula: Oil absorption (%) = H/Sx100.

Particle size distribution is determined as follows:

S (g), which is about 60g, of a sample is placed in a Rotap sieve analyzer, followed by sieving the sample. The weight D (g) of the sample remaining on each net is measured. The particle size distribution is determined according to the formula: Particle size distribution (%) = D/Sx100.

Kaga Balloon is available at KAGALITE KOGYO Co., Ltd., Japan.

The solid pesticidal active ingredients to be used in the instant invention can be insecticides, fungicides, herbicides and/or plant growth regulators. The "solid pesticidal active ingredients" used in the instant invention are those which are solids at 20°C under standard atmospheric conditions.

Examples of solid herbicides include Bifenox, Oxadiazon, Pentoxazone, Carfentrazone-Ethyl, Oxadiargyl, Pyrachlonil, Butachlor, Pretilachlor, Thenylchlor, Piprerophos, Benslide, Butamifos, Anilofos, Thiobencarb, Molinate, Esprocarb, Dimepimerate, Pyributicarb, Cafenstrole, Indanofan, Mefenacet, Fentrazamide, Etobenzanid, Dithiopyr, Oxaziclomefon, Cinmethylin, Pyriminobac-Methyl, Pyriftalid, Cyhalof op-Butyl, Metamifop, Daimuron, Cumyluron, Bromobutide, Benfuresate. Bensulfuron-Methyl, Azimsulfuron, Pyrazosulfuron-Ethyl, Cinosulfuron, Imazosulfuron, Cyclosulfamuron, Ethoxysulfuron, Halosulfuron-Methyl, Pyrazolate, Pyrazoxyfen, Benzofenap, Benzobicyclon, Naproanilide, Clomeprop, MCP, MCPB, Phenothiol, Bentazon, Simetryn, Prometryn, Dimethametryn and Quinoclamine.

Examples of solid fungicides include Acibenzolar-S-Methyl, Ipconazole, Iprodione, Oxolinic acid, Kasugamycin, Capropamide, Captan, Thiabendazole, Thiuram, Thiophanatemethyl, Organocopper, Tricyclazole, Triflumizole, Varidamycin, Azoxystrobin, Pyroquilon, Fludioxonyl, Prochloraz, Probenazol, Benomil, Metasulfocarb, TPN, Oryzastrobin and

Metominostrobin.

Examples of solid insecticides include Isoprothiolan, Imidachloprid, Ethofenprox, Cartap,

Thiamethoxam, Bensultap, Benthiocarb, Monocrotofos and Alprocarb, Clothianidin,

Dinotefran, Acetamiprid, Thiacloprid, Fipronil and Ethiprole.

Examples of solid plant regulators include Paclobutrazole, Trinexapac-ethyl, Uniconazole-P,

Inabenfide and Prohexadione-calcium.

These solid active ingredients can be used alone or in combination. If they are used in combination, the ratio at which they are combined should be determined by a person skilled in the art.

The surfactant to be used in the instant invention may be solid or liquid at room temperature and may be anionic or nonionic. Such a surfactant preferably exhibits an ability to reduce the surface tention of water down to 40dyn/cm or less in a 0.1% aqueous solution.

Examples of anionic surfactants to be used in the instant invention include:

Salts of polystyrenesulfonic acid, in particular the alkali metal, alkaline earth metal and ammonium salts;

Salts of polyvinylsulfonic acid, in particular the alkali metal, alkaline earth metal and ammonium salts;

Salts of condensates of naphthalenesulfonic acids, preferably naphthalene-2-sulfonic acid, with formaldehyde, in particular the alkali metal, alkaline earth metal and ammonium salts;

Salts of condensates of naphthalenesulfonic acid with phenolsulfonic acid and formaldehyde, in particular the alkali metal, alkaline earth metal and ammonium salts;

Salts of ligninsulfonic acid, in particular the sodium, potassium, magnesium, calcium or ammonium salts;

Salts of naphthalenesulfonic acids, in particular the alkali metal, alkaline earth metal and ammonium salts; and

Salts of dialkylsulfosuccinic acids, in particular the alkali metal, alkaline earth metal and ammonium salts.

Examples of nonionic surfactants to be used in the instant invention are polyvinyl alcohol, polyvinyl methyl ether, polyvinylpyrrolidone, alkylated polyvinylpyrrolidone, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose (degree of substitution: 1.5 to 2), hydroxyethylmethyl cellulose, hydroxypropylmethyl cellulose, poly(2-hydroxyethyl)methacrylate, poly[2-(2-hydroxyethoxy)ethyl]methacrylate, polyethylene oxide (polyoxyethylene) and polyallyl alcohol (polyglycidol);

Products which can be obtained by reaction of ethylene oxide, or by the combined reaction of ethylene oxide and propylene oxide, with fatty alcohols, alkyl phenols, styrenephenols, fatty acids, fatty acid esters of polyhydroxy compounds, castor oil, fatty acid amides and fatty amines, where the number of ethylene oxide and propylene oxide units may vary within wide limits. In general, the number of ethylene oxide units or ethylene oxide and propylene oxide units is from 1 to 200, preferably from 5 to 100 and, most preferably, from 8 to 40.

Particularly preferred surfactant is sodium dialkylsulfosuccinate or a product, which is obtained by reaction of ethylene oxide, or by the combined reaction of ethylene oxide and propylene oxide, with compounds selected from the group of fatty alcohols, alkyl phenols, styrenephenols, fatty acids, fatty acid esters of polyhydroxy compounds, castor oil, fatty acid amides and fatty amines; a suitable example of the latter is Noigen ET102 (a product of Daiich-Kogyo-Seiyaku Co. Ltd, a polyoxyethlene lauryl ether which has 5 molar in average of oxyethylen unit in), which is a surfactant obtained by reaction of ethylene oxide with a fatty alcohol.

These surfactants, including the particularly preferred one, can be used alone or in combination. If they are used in combination, the ratio at which they are combined should be determined by a person skilled in the art.

The oily substances to be used in the instant invention are in general hydrophobic liquids, such as olive oil, palm oil, soybean oil, liquid paraffin or the like. If desired, liquid pesticidal active ingredients can also be used as an oily substance. In such cases, the formulation according to the instant invention contains liquid- as well as solid pesticidal active ingredients, thereby performing a plurality of pesticidal effects.

Such liquid pesticidal active ingredients can be herbicides, fungicides, insecticides and/or .planr growth regulators.

Examples of liquid insecticides include cyanophos, fenthion, fenitrothion, dichlofenthion, pirimiphos-methyl, diazinon, isoxathion, oxydeprofos, malathion, phenthoate, formothion, thiometon, disulfoton, prothiofos, sulprofos, profenofos, pyraclofos, dichlorvos, naled, chlorfenvinphos, propaphos, isofenphos, ethion, carbosulfan, benfuracarb, allethrin, permethrin, cyhalothrin, cyfluthrin, fenvalerate, flucythrinate, fluvalinate, cycloprothrin, silafluofen, potassium oleate, propargite, halfenprox, ethoprophos, fosthiazate, chlorpicrin and metam-ammoniunL

Examples of liquid fungicides include calcium polysulfide, edifenphos, propiconazole, pefurazoate, pyrifenox, tetraconazole, echlomezol, dinocap, metalaxyl-M and benthiazole. Examples of liquid herbicides include triclopyr, fluazifop, orbencarb, esprocarb, molinate, pretilachlor, metolachlor, dimethenamid, pelargonic acid, dalapon, piperophos, butamifos, glyphosate-trimesium, sethoxydim, clethodim, S-metalachlor and cynmethylin. Examples of liquid plant regulators include mepiquat-chloride, decylalcohol and piperonyl butoxide.

Among the above oily substances, soybean oil and liquid parafine are particularly preferred.

These oily substances, including the particularly preferred one, can be used alone or in combination. If they are used in combination, the ratio at which they are combined should be empirically determined by the person skilled in the art.

The surfactant and the oily substance are admixed in a weight ratio of usually 100:1-100:100, preferably 100:2-100:80, more preferably 100:5-100:60, most preferred 100:10-100:40, thereby obtaining the mixture comprising at least one surfactant and at least one oily substance. If a combination of liquid surfactants and/or a combination of oily substances are used in the mixture, the total weight of the liquid surfactants and/or the total weight of the oily substances are respectively regarded as the weight of the surfactant and/or the weight of the oily substance.

In a preferred embodiment of the instant invention, the solid pesticidal active ingredient is used in an amount of 10-50%, preferably 15-40%, by weight, the mixture comprising at least one surfactant and at least one oily substance in an amount of 1-30%, preferably 5-20%, by weight, based on the total weight of the formulation.

It is sometimes advantageous that a carrier is also adhered to the surface of Kaga Balloon particles coated with the mixture comprising at least one surfactant and at least one oily substance. Examples of such carriers include water-soluble salts e.g. ammonium sulfate, ammonium nitrate and sodium acetate; sugars e.g. glucose, lactose and fructose; water-soluble polymers e.g. polyvinyl alcohol and polyvinyl acetate; natural mineral fillers e.g. zeolite, calcite, talcum, kaolin, montmorillonite and attapulgite; highly dispersed silisic acid; highly dispersed absorbent polymers; porous materials e.g. broken brick, sepiolite, white carbon and bentonite.

This carrier or a mixture of carriers can be used alone or in combination with the pesticidal active ingredient, the weight ratio of which should be determined by a person skilled in the art. If a carrier is to be adhered, the amount thereof should be selected such that the total amount of the solid pesticidal active ingredient and the carrier is 10-60%, preferably 15-60%, by weight based on the total weight of the formulation. If a liquid pesticidal active ingredient is used as an oily substance in the preparation of the mixture comprising at least one surfactant and at least one oily substance, it is preferred that a porpous carrier e.g. white carbon is also adhered to the surface of Kaga Balloon.

The process for the production of the pesticidal formulation according to the instant invention is extraordinarily simple. Firstly, a mixture comprising at least one surfactant and at least one oily substance is prepared. Then, Kaga Balloon particles are coated with the thus prepared mixture, onto which at least one powdered pesticidal active ingredient optionally with a powdered carrier is adhered, thereby yielding the formulation according to the instant invention.

The mixture comprising at least one surfactant and at least one oily substance is prepared simply by admixing at least one surfactant and at least one oily substance in amounts as mentioned above. If the surfactant is liquid and unacceptably viscose at room temperature, then such liquid surfactant should be heated to a temperature at which the viscosity thereof is sufficiently reduced and, thereafter, the surfactant is admixed with the oily substance. If the surfactant is a solid, then it should have a particle size of 1-100_/2 m, preferably 1-50 μ m. Adjustment of the particle diameter can be done for example by ball-milling. The preparation of the mixture is carried out using appropriate mixing/stirring means well known in the art e.g. a mixer. The soild pesticidal active ingredient to be adhered to the surface of Kaga Balloon particles is a powder having a particle size of usually 1-300 μ m, preferably 1-200 μ m, more preferably 1-100 m, most preferred 1-50 μ. m. Such a powdered solid pesticidal active ingredient can be prepared simply by grinding a solid pesticidal active ingredient by means of any commonly applied equipment e.g. a ball mill, a pin mill or the like. If a carrier is also to be adhered to the surface of Kaga Baloon particles, the desired carrier is subject to grinding in the same manner as mentioned above and, then, uniformly mixed with the above prepared powdered solid pesticidal active ingredient using appropriate mixing means e.g a ribbon mixer. Particle size of the water-soluble carrier is usually 1-300 μ m, preferably 1-200 μ m, more preferably 1-100 μ m, most preferred 1-50 m. From the viewpoint of reduction in process steps, it is advantageous to grind, using a piece of equipment as mentioned above, a mixture from a carrier and a solid pesticidal active ingredient and, then, subject to further mixing by appropriate mixing means e.g. a ribbon mixer. If more than one solid pesticidal active ingredients and/or carriers are to be adhered to the surface of Kaga Balloon particles, mixtures of such solid pesticidal active ingredients and/or carriers, admixed in desired weight ratios, are ground and/or mixed as mentioned above.

Coating of Kaga Balloon particles with the mixture comprising at least one surfactant and at (east one oily substance is carried out by any method known in the art. For example, a desired amount of Kaga Baloon is charged into a mixer e.g. a concrete mixer, to which said mixture is sprayed or dropped till the surface of each Kaga Balloon particle becomes uniformly wet, i.e. coated with the mixture, with the mixer being operated, i.e. the Kaga Balloon particles being mixed/stirred. Subsequently, the above prepared powdered solid pesticidal active ingredient or the powdered mixture of solid pesticidal active ingredient and carrier is added to the Kaga Balloon particles coated with the mixture comprising at least one surfactant and at least one oily substance with the mixer being operated. The mixer is kept operating till the solid pesticidal active ingredient and the carrier, if any, uniformly adhere to the surface of each of the Kaga Balloon particles, thereby obtaining the formulation according to the instant invention. The powdered solid pesticidal active ingredient or the powdered mixture of solid pesticidal active ingredient and carrier can be added at once or dividedly in some parts.

For the preparation of the formulation of the instant invention, the powdered solid pesticidal active ingredient is used in a amount of 10-50%, preferably 15-40%, by weight, the mixture comprising at least one surfactant and at least one oily substance in an amount of 1-30%, preferably 5-20%, by weight, based on the total weight of the formulation. If also a carrier is to be adhered, the amount thereof should be selected such that the total amount of the solid pesticidal active ingredient and the carrier is 10-60%, preferably 15-60%, by weight based on the total weight of the formulation.

The formulation according to the instant invention is preferably wrapped in a bag made of a water-soluble polymer such as polyvinylalcohol, polyvinylacetate, polyvinylpyrrolidone, carboxymethylcellulose or the like. By employing this technique, it is enabled to apply the formulation according to the instant invention without being exposed thereto. The amount of formulation to be contained in the water-soluble bag is 5-200g, preferably 10-150g, most preferred 15-100g. Another possible way of application of the formulation according to the instant invention is to pack it in bottles or bags having a hole through which the formulation can be scattered. By employing this technique, the formulation of the instant invention can, due to its excellent spreadability, be applied in the same manner as the flowable formulations which are scattered from the sides of the rice fields.

Examples

The instant invention will further be explained with reference to the following examples, which of course are meant to illustrate the invention .

Preparation Examples

Example 1

Firstly, 25.5 parts by weight of Pyroquilon tech. (a fungicide of Syngenta Japan K.K.) and 24.5 parts by weigt of ammonium sulfate were admixed and milled by means of a commercially available pin mill operating at a rotation speed of 500-1 OOOrpm to thereby obtain a solid mixture. Then, 2 parts by weight of New Kargen EP-70G (a sodium dialkyl sulfosuccinate, a product of Takemoto Yushi Co., Ltd.) and 8 parts by weight of liquid parafine were admixed to obtain a liquid mixture, which liquid mixture was then gradually added to 40 parts by weight of Kaga Balloon No. 3 (a Product of Kagalite Kogyo Co., Ltd.) placed in the drum of a commercially available coating pan operating at a rotation speed of 20-60rpm, whereby each of the particles of Kaga Balloon No. 3 was uniformly coated with said liquid mixture. Subsequently, the above prepared solid mixture was gradually added to the thus coated Kaga Balloon No. 3 with the coating pan being kept operating at the rotation speed of 20-60rpm, whereby the particles of the solid mixture adhered uniformly to the surface of each of the particles of Kaga Balloon No.3, thereby yielding a formulation of the instant invention. The adhesion of the particles of solid mixture took about 5 minutes.

After completion of the above process, the thus obtained formulation was taken out of the drum of the coating pan and the particles of solid mixture not adhered to the surface of particles of Kaga Balloon No. 3 were removed by shaking the formulation on a 500 μ m mesh sieve. By measuring the weight of formulation remaining on the sieve, it was determined that the yield of the formulation was 98%. Visual observation revealed that the particles of the solid mixture uniformly adhered to the surface of the particles of Kaga Balloon No. 3.

Example 2

A formulation of the instant invention was prepared in the same manner as in Example 1 except that 46 parts by weight of Pyroquilon tech. and 4 parts by weight of ammonium sulfate were respectively used in place of 25.5 parts by weight of Pyroquilon tech. and 24.5 parts by weight of ammonium sulfate. The yield of this formulation was 98%. Visual observation revealed that the particles of the solid mixture uniformly adhered to the surface of the particles of Kaga Balloon No. 3.

Example 3

A formulation of the instant invention was prepared in the same manner as in Example 1 except that 46 parts by weight of Thiamethoxam (an insecticide of Syngenta Japan K.K.) and 4 parts by weight of ammonium sulfate were respectively used in place of 25.5 parts by weight of Pyroquilon tech. and 24.5 parts by weight of ammonium sulfate. The yield of this formulation was 98%. Visual observation also revealed that the particles of the solid mixture uniformly adhered to the surface of the particles of Kaga Balloon No. 3. Example 4

A formulation of the instant invention was prepared in the same manner as in Example 1 except that 2 parts by weight of Noigen ET102 (polyoxyethlene lauryl ether which has 5 molar of oxyethylen unit in, a product of Daiich-Kogyo-Seiyaku Co. Ltd.) and 8 parts by weight of soybean oil were respectively used in place of 2 parts by weight of New Kargen EP-70G (a sodium dialkyl sulfosuccinate, a product of Takemoto Yushi Co., Ltd.) and 8 parts by weight of liquid parafine. The yield of this formulation was 98%. Visual observation also revealed that the particles of the solid mixture uniformly adhered to the surface of the particles of Kaga Balloon No. 3.

Comparative Example 1

A comparative formulation was prepared in the same manner as in Example 2 except that 40 parts by weight of Pearlite L (foamed Kagalite, a product of KAGALITE KOGYO Co., LTD.) were used in place of 40 parts by weight of Kaga Balloon No. 3. The yield of this comparative formulation was 92%. Due to the brittleness of Peralite L, it was observed that many particles thereof were crashed during the preparation of this comparative formulation.

Comparative Example 2

A comparative formulation was prepared in the same manner as in Example 2 except that 40 parts by weight of G-Lite (foamed glass, a product of KAGALITE KOGYO Co., LTD.) were used in place of 40 parts by weight of Kaga Balloon No. 3. The yield of this comparative formulation was 71%. It was observed that the adhesion of the particles of the solid mixture to the surface of the particles of G-Lite was insufficient. Many particles of the solid mixture remained unadhered and sticked to the wall of the drum of the coating pan.

Comparative Example 3

A comparative formulation was prepared in the same manner as in Example 2 except that 40 parts by weight of Cork (milled cork, a product of KAGALITE KOGYO Co., LTD.) were used in place of 40 parts by weight of Kaga Balloon No. 3. The yield of this comparative formulation was 80%. It was observed that the adhesion of the particles of the solid mixture to the surface of the particles of Cork was insufficient. Many particles of the solid mixture remained unadhered.

Comparative Example 4

A comparative formulation was prepared in the same manner as in Example 2 except that 40 parts by weight of Bermiculite (bermiculite, a product of KAGALITE KOGYO Co., LTD.) were used in place of 40 parts by weight of Kaga Balloon No. 3. The yield of this comparative formulation was 91%. It was observed that the adhesion of the particles of the solid mixture to the surface of the particles of Bermiculite was insufficient. Many particles of the solid mixture remained unadhered.

Test Examples

Test Example 1

Into a container whose width, height and length are respectively 10cm, 10cm and 4m, 20 I of water were poured so as to adjust the depth thereof to 5cm. Then, 5g of the formulation prepared in Example 1 were put on the surface of the thus filled water at a position 50cm distant from one end of this container. Time required for the formulation to reach a position 1 , 2 or 3 meters distant from the position at which the formulation was put was measured. The time thus measured was respectively 9, 23 or 40 sec. After the particles of the formulation terminated their motion, floatability, and uniformity of diffusion, of the particles were visually observed. The floatability and uniformity of diffusion of the particles were both excellent. Moreover, it was also examined whether there was any sedimentation of the particles at the position at which the formulation was put after the particles of the formulation substantially terminated their motion. This examination revealed that there was almost no such sedimentation.

Test Example 2

Tests were carried out in the same manner as in Test Example 1 except that the formulation prepared in Example 2 was used in place of the formulation prepared in Example 1. Time required for reaching the the position 1 , 2 or 3 meters distant from the position at which the formulation was put was respectively 9, 22 or 39 sec. The floatability and uniformity of diffusion of the particles were both excellent. There was observed a little sedimantation at the position at which the formulation was put.

Test Example 3

Tests were carried out in the same manner as in Test Example 1 except that the formulation prepared in Example 3 was used in place of the formulation prepared in Example 1. Time required for reaching the the position 1 , 2 or 3 meters distant from the position at which the formulation was put was respectively 10, 23 or 40 sec. The floatability and uniformity of diffusion of the particles were both excellent. There was observed a little sedimantation at the position at which the formulation was put.

Test Example 4

Tests were carried out in the same manner as in Test Example 1 except that the formulation prepared in Example 4 was used in place of the formulation prepared in Example 1. Time required for reaching the the position 1 , 2 or 3 meters distant from the position at which the formulation was put was respectively 11 , 27 or 50 sec. The floatability and uniformity of diffusion of the particles were both excellent. There was observed a little sedimantation at the position where the formulation was put.

Comparative Test Example 1

Tests were carried out in the same manner as in Test Example 1 except that the formulation prepared in Comparative Example 1 was used in place of the formulation prepared in Example 1. Time required for reaching the the position 1 , 2 or 3 meters distant from the position at which the formulation was put was respectively 11 , 27 or 53 sec. The floatability of the particles was poor and some particles sedimented while the diffusion of the particles was uniform. There was observed more sedimantation of particles than in Test Examples 1-3 at the position at which the formulation was put. Comparative Test Example 2

Tests were carried out in the same manner as in Test Example 1 except that the formulation prepared in Comparative Example 2 was used in place of the formulation prepared in Example 1. Time required for reaching the the position 1 , 2 or 3 meters distant from the position at which the formulation was put was respectively 19, 41 or 110 sec. The floatability of the particles was good. However, the particles tended to aggregate and the uniformity of diffusion was very poor. There was observed profound sedimantation of particles at the position at which the formulation was put.

Comparative Test Example 3

Tests were carried out in the same manner as in Test Example 1 except that the formulation prepared in Comparative Example 3 was used in place of the formulation prepared in Example 1. Time required for reaching the the position 1 , 2 or 3 meters distant from the position at which the formulation was put was respectively 5, 15 or 28 sec. The floatability of the particles was good. However, most of the particles tended to remain within the region between the position at which the formulation was put and a position 1 meter distant therefrom and, consequently, the uniformity of diffusion was very poor. There was observed a little sedimantation of particles at the position at which the formulation was put.

Comparative Test Example 4

Tests were carried out in the same manner as in Test Example 1 except that the formulation prepared in Comparative Example 4 was used in place of the formulation prepared in Example 1. Time required for reaching the the position 1 , 2 or 3 meters distant from the position at which the formulation was put was respectively 21 , 44 or 120 sec. The floatability of the particles was poor and some particles sedimented. The particles tended to aggregate and the uniformity of diffusion was very poor. There was observed profound sedimantation of particles at the position at which the formulation was put.

As described above, the instant invention provides pesticidal formulations with high active ingredient content, which diffuses rapidly, uniformly and substantially without sedimentation over the surface of water, efficientcly releasing pesticidal active ingredients throughout the water surface, thereby saving labor load of growers, storage volume during distribution as well as production costs thereof to a large extent. The instant invention is therefore extraordinarily valuable in view of current state of modern agriculture and agrochemicals industry as well.

Claims

What is claimed is:

1. A process for the preparation of a pesticidal formulation comprising the steps of

(a) mixing at least one surfactant with at least one oily substance

(b) coating Kaga Balloon particles with the mixture obtained in step (a) in a mixer

(c) adhering at least one pesticidal active ingredient to the coated Kaga Balloon particles obtained in step (b).

2. A process according to claim 1 , wherein at least one carrier is adhered to said particles obtained in step (c).

3. A process according to claim 1 , wherein a mixture of at least one pesticidal active ingredient with at least one carrier is adhered to said coated Kaga Balloon particles obtained in step (b).

4. A process according to claim 1 , wherein the pesticidal active ingredient is selected from the group consisting of insecticides, fungicides, herbicides and plant growth regulators.

5. A process according to claims 4, wherein said pesticidal active ingredient is solid.

6. A process according to claims 1 , wherein said oily substance is a liquid pesticidal active ingredient selected from the group consisting of insecticides, fungicides, herbicides and plant growth regulators.

7. A process according to claim 1 , wherein said surfactant exhibits an ability to reduce the surface tention of water down to 40 dyn/cm or less in a 0.1% aqueous solution.

8. A process according to claim 1 , wherein said surfactant is sodium dialkylsulfosuccinate.

9. A process according to claim 1 , wherein said surfactant is obtained by reaction of ethylene oxide, or by the combined reaction of ethylene oxide and propylene oxide, with a compound selected from the group of fatty alcohols, alkyl phenols, styrenephenols, fatty acids, fatty acid esters of polyhydroxy compounds, castor oil, fatty acid amides and fatty amines.

10. A process according to claim 1 , wherein said oily substance is selected from the group consisting of olive oil, palm oil, soybean oil and liquid paraffin.

11. A pesticidal formulation comprising particles coated with a surfactant, an oily substance and a pesticidal active ingredient characterised in that the particles are Kaga Balloon particles coated by a first layer comprising at least one surfactant and at least one oily substance, and by a second layer which is coated to the first layer comprising the solid pesticidal active ingredient.

12. A pesticidal formulation according to claim 10, characterised in that the second layer additionnaly contains at least one carrier.

13. An agrochemical product comprising a solid pesticidal formulation produced by a process according to claim 1.

14. An agrochemical product in form of a water-soluble bag made of water-soluble polymer, characterised in that it contains a solid pesticidal formulation produced by a process according to claim 1.

15. The use of the agrochemical product according to claims 12 and 13 in paddy fields.