WO1998021960A1

WO1998021960A1 - Novel solid compositions with base of insoluble cellulose derivative and 1-aryl-pyrazole derivative

Info

Publication number: WO1998021960A1
Application number: PCT/FR1997/002066
Authority: WO
Inventors: Marc Grenet; Masato Kobayakawa; Norihiko Nakakura; Takashi Nakatsui; Günther Maurer; Eberhard Teufel
Original assignee: Rhone-Poulenc Agrochimie
Priority date: 1996-11-22
Filing date: 1997-11-17
Publication date: 1998-05-28
Also published as: MA24403A1; AU5225798A; HRP970631A2; TNSN97186A1

Abstract

The invention concerns a solid composition of a water-insoluble cellulose derivative containing an effective amount of at least a 1-arylpyrazole derivative more particularly a composition in which the 1- arylpyrazole derivative is distributed homogeneously in the insoluble cellulose derivative, in particular in the form of a solid solution. The invention also concerns a method for preparing the above compositions and their use in fighting against insect pests, particularly against termites.

Description

New solid compositions based on insoluble cellulose derivative and 1-aryl-pyrazole derivative.

The present invention relates to a new insecticidal composition based on 1-aryl pyrazole derivative, its preparation process and its use for the control of harmful insects.

The interest of 1-arylpyrazoles in combating insects, in particular against termites, is known from patent applications WO 87/3781. WO 93/6089, WO 94/21606 or EP 2951 17. Different formulations of 1 -arylpyrazoles are described in the state of the art, in particular in the form of powders, gels, aqueous concentrated suspensions or emulsifiable compositions based on a weakly polar solvent and an emulsifying agent (WO 96/16544)

One of the main problems for the formulation of an insecticidal compound is that of preventing the insecticidal compound from coming into contact with the user of the formulation.

The object of the present invention consists of a new formulation of derivative of 1 -arylpyrazoles concentrated homogeneous and stable over time, which is effective against harmful insects, in particular against termites, while allowing easy handling and improved safety .

The present invention therefore relates to a new solid composition of a water-insoluble cellulose derivative comprising an effective amount of at least one 1-arylpyrazole derivative.

Advantageously, the term 1 -arylpyrazole according to the invention means a compound of general formula (I)

in which,

Ri is a halogen atom or a CN or methyl group; R ₂ is S (O) _n R ₃ ; R ₃ is an alkyl or haloalkyl radical; R represents a hydrogen or halogen atom; an alkyl radical. haloalkyl

NR ₅ R ₆ , -S (O) _m R ₇ , C (O) R ₇ , -C (O) OR ₇ , -N = C (R ₉ ) (R, ₀ ) or -OR ₈ . R ₅ and R ₆ represent, independently of one another, a hydrogen atom, an alkyl, haloalkyl, -C (O) alkyl, -S (O) _r CF3 radical; or R5 and R ₆ may together form a divalent alkylene radical which may be interrupted by one or two divalent heteroatoms, such as oxygen or sulfur; R ₇ represents an alkyl or haloalkyl radical; Rg represents an alkyl, haloalkyl radical or a hydrogen atom; R ₉ represents an alkyl radical or a hydrogen atom; Rio represents a phenyl or heteroaryl group optionally substituted by one or more halogen atoms or groups such as OH, -O-alkyl, -S-alkyl, cyano, or alkyl; X represents a trivalent nitrogen atom or a C-R12 radical, the other three valences of the carbon atom being part of the aromatic ring; Rn ^and R-12 represent, independently of one another, a hydrogen or halogen atom; Ri 3 represents a halogen atom or a haloalkyl, haloalkoxy group, -

S (O) _q CF ₃ or -SF ₅ ; m, n, q, r represent, independently of one another, an integer equal to 0.1 or 2; with the proviso that, when R _] is methyl, then R ₃ is a haloalkyl group, R ₄ is NLb. A.! ₁ is Cl, R ₁₃ is CF ₃ , and X is N.

According to the present invention, alkyl radicals mean straight or branched chain alkyl radicals, and generally comprise from 1 to 6 carbon atoms. This definition also applies to the alkyl radicals comprising radicals comprising an alkyl part, such as the alkoxy, alkylthio, alkylcarbonyl, haloalkyl or haloalkoxy radicals.

Advantageously, the ring formed by the divalent alkylene radical representing R5 and Rg as well as by the nitrogen atom to which R5 and Rg are attached, is a 5, 6 or 7-membered ring.

According to the present invention, the term “halogen atom” means fluorine, chlorine, bromine or iodine atoms, preferably fluorine or chlorine. This definition also applies to the halogen atoms of the haloalkyl or haloalkoxy radicals.

A preferred class of compounds of formula (I) consists of the compounds such that R 1 is CN, and / or R ₃ is haloalkyl, and / or R ₄ is NH ₂ , and / or R ₁ and R ₁₂ are independently the one of the other a halogen atom, and / or R ₁₃ is haloalkyl. A compound of formula (I) very particularly preferred in the invention is l- [2,6-Cl ₂ 4-CF ₃ phenyl] 3-CN 4- [SO-CF ₃ ] 5-NH ₂ pyrazole. hereinafter referred to as fipronil.

The preparation of compounds of formula (I) can be carried out according to one or other of the methods described in patent applications WO 87/3781, 93/6089, 94/21606 or European patent 295117, or any other method relating to the skill of a person skilled in the art of chemical synthesis.

The insoluble cellulose derivative can be in the form of powder, particles, granules, fibers, woven or nonwoven webs, etc. The insoluble cellulose derivative is advantageously an aliphatic cellulose ester, preferably a cellulose acetate, more preferably a cellulose acetate, the degree of polymerization of which is between 150 and 250 units, preferably between 150 and 220 and / or one degree acetylation between 1.2 and 2.8, preferably between 1.9 and 2.5. The effective amount of 1-arylpyrazole derivative in the composition according to the invention will depend on the final form of the insecticidal composition, its use and the target insects of said composition.

Advantageously, the effective amount of 1-arylpyrazole derivative in the composition according to the invention is between 0.0001 and 50% by weight relative to the total weight of the composition, preferably between 0.05 and 25% in weight.

The composition according to the invention can be in different solid forms, in the form of fibers, woven or nonwoven webs obtained with said fibers, in the form of solid particles or also of granules.

For a composition in the form of fibers, the effective amount of 1-arylpyrazole derivative is advantageously between 0.1 and 15% by weight.

For a composition in the form of woven or nonwoven webs, the effective amount of 1-arylpyrazole derivative is between 0.01 and 25 g / m ^, advantageously between 0.1 and 10 g / m ^, or even for some uses between 1 and 5 g / m ^. For a composition in the form of particles, the effective amount of derivative of

1 -arylpyrazole is advantageously between 0.05 and 10% by weight.

For a composition in the form of granules, the effective amount of 1-arylpyrazole derivative is advantageously less than approximately 10% by weight, preferably less than 7% by weight, more preferably between 0.05 and 5% by weight. Fibers

When the composition according to the invention is in the form of fibers, the fibers are cut into fragments of size generally between approximately 2 and approximately 30 mm, preferably between approximately 6 and approximately 18 mm. In addition, the fibers of the composition according to the invention may have a section of various shape, such as circular, in "Y", in "X", or in "I". Their weight per unit of length varies from approximately 1 to approximately 25 decitex, a range of 1 to 5 decitex being more particularly preferred for a more effective release of 1 -arylpyrazole over time. One decitex is the weight expressed in grams per 10,000 m of fiber. The corresponding average diameter is generally between approximately 10 and approximately 100 μm, preferably from 15 to 50 μm. Tablecloths When the composition according to the invention is in the form of a woven or nonwoven web obtained with the above fibers, it preferably has a thickness of between approximately 0.05 mm and approximately 2 cm, preferably between 0.1 and 1 cm, and depending on use, more preferably between 1 and 5 mm. The weight per m ^ of the sheet according to the invention is advantageously between approximately 1 and approximately 2500 g / m ^. It will depend in particular on the subsequent use of the sheet according to the invention. In the case of a tablecloth to be deposited under the foundations of a house to fight against termites, the weight per m ^ of the tablecloth according to the invention is preferably between 100 and 1000 g / m.2. In the case of a tablecloth useful as a support for germination and cultivation of seeds, in particular rice, to protect them against insects, the weight per m 2 of the tablecloth according to the invention is advantageously between 5 and 100 g / rn- ^. preferably between 10 and 70 g / m ^.

According to a preferred embodiment of the invention, the sheet has an air permeability of between approximately 50 and approximately 10,000 ls ^~ lm "2, preferably between 70 and 5000 ls" lm "2. The permeability to air is measured by the amount of air that passes through two opposite surfaces of a standard surface of the web (approximately

20 to 50 cm ^) according to one of the following equivalent standard methods: ISO9237, AFNOR G07-111, ASTM D737 or DIN 53887.

The dimensions of the woven or nonwoven webs according to the invention will vary according to their method of manufacture and their use. It can for example be a large tablecloth to be deposited under the foundations of a house to fight against termites. In this case, the width of the sheet according to the invention is between approximately 20 cm and approximately 4 m, advantageously between 30 cm and 3 m.

When the tablecloth according to the invention is used as a support for seeds and crops, it can advantageously be used in a sowing box. Sowing boxes, also called in English "seeding box" or "nursery box", are commonly used by rice farmers to obtain, after sowing, seedlings of rice which are then conveniently transplanted (or transplanted) into submerged rice fields, usually by mechanical means. The tablecloth according to the invention is very simply placed by the rice cultivator in a sowing box. It suffices to place it on a first layer of soil, generally between 1 and 5 cm in height. The rice grains are sown on the tablecloth, and the whole is covered with a second layer of soil, generally between 0.5 and 2 cm in height. The height of the first layer of soil is generally between 1 and 5 cm. The height of the second soil layer, also called the surface layer, is advantageously between 0.5 and 2 cm, preferably between 1 and 2 cm. The bottom of the box can be covered, under the first layer of soil, with a paper usually qualified in English as a "liner" of weight per unit of suitable surface. This variant is particularly advantageous when the seed boxes are stored on the ground. during the period of time between sowing and transplanting. In fact, in the absence of such a layer of paper, the roots of the rice seedlings would be likely to cross the bottom of the box (pierced with multiple holes to facilitate the flow of the irrigation water), and to take root in the ground; which could damage the rice seedlings, and would considerably hamper the removal of the boxes for transplanting. The weight per unit area of the liner is generally between 20 and 80 g / m ² , preferably between 30 and 50 g / m ² . The size of the sowing box and the tablecloth is usually chosen to correspond to 100 to 300 boxes per hectare of culture, preferably 200 boxes. These boxes are generally rectangles of length usually between 50 and 65 cm, and of width between 20 and 35 cm. A rectangle of 58 by 28 cm is commonly used. The quantity of rice seeds contained in the boxes corresponds to a sowing of 10 to 300 kg / ha, preferably from 20 to 200 kg / ha.

Particles

When the solid composition according to the invention is in the form of particles, it is advantageously microparticles of substantially spherical shape and of a size between approximately 0.3 and approximately 200 μm, preferably between 1 and 50 μm, again more preferably between 5 and 20 μm. By the term substantially spherical, according to the invention is meant a shape which can be approached geometrically by a sphere or an ellipsoid, and which can be described by a single size parameter. These microparticles have an advantageous suspension in water.

According to a preferred embodiment of the invention, the microparticles are hollow and are in the form of an envelope or shell with a thickness of between 0.1 and 3 μm, preferably between 0.5 and 1.5 μm. Such a thickness is particularly suitable for termites which can consume microparticles with greater ease, improving the effectiveness of 1-arylpyrazole derivatives against these insects.

An advantageous measurement technique for measuring the thickness of the envelope consists in including 0.1 g of microparticles in a 5% agarose gel, in bringing the said gel to a temperature of - 40 ° C, and cutting at this temperature with a steel blade. The cutting surface is then observed by environmental scanning microscopy, the sample being placed in an observation chamber in the presence of water vapor at a pressure between 5 and 12 mmHg. A magnification of around 1000 is used.

Pellets

The granules according to the invention preferably have a length of between approximately 0.5 and 2 mm, preferably of approximately 1 mm, and an average diameter of between approximately 0.5 and 2 mm, preferably of approximately 1 mm. . Such a size of granules is particularly suitable for the fight against termites.

The composition according to the invention can also comprise the usual additives used in the preparation of the various forms above. Among these additives, mention may be made of binders, dyes, surfactants, diluents or plasticizers. The binders are particularly suitable for the preparation of woven or nonwoven fibrous webs according to the invention. Among the binders used, a binder soluble or dispersible in water is preferred, generally in the form of cut fibers. Such binders are well known in the art. These are water-soluble or water-dispersible polymers, which are either natural polymers such as polysaccharides, or semi-synthetic polymers such as carboxymethylcellulose and its salts, or synthetic polymers, such as polyvinyl alcohol or polyvinylpyrrolidone. Polyvinyl alcohol is particularly preferred.

In the sheets according to the invention, the weight ratio of binder / weight of fibers comprising the agrochemical product is generally between 1 and 20%, preferably between 5 and 15%.

Surfactants and diluents are particularly suitable for the compositions according to the invention in the form of particles which can advantageously be used in pesticidal compositions comprising at least 50

%, preferably at least 95% of particles as described above, in combination with at least one surfactant, and optionally a diluent.

The surfactant can be a dispersing or wetting agent of ionic type or non-ionic or a mixture of such surfactants. Mention may be made, for example, of salts of polyacrylic acids, of salts of lignosulfonic acids. salts of phenolsulfonic or naphthalenesulfonic acids, polycondensates of ethylene oxide on fatty alcohols or on fatty acids or on fatty amines, substituted phenols (in particular alkylphenols or arylphenols), salts of esters of sulfosuccinic acids, taurine derivatives (in particular alkyltaurates), phosphoric esters of polyoxyethylated alcohols or phenols, esters of fatty acids and of polyols, the derivatives containing sulfates, sulfonates and phosphates of the above compounds. By the term "diluent" is meant according to the invention an organic or mineral, natural or synthetic material, with which the particles according to the invention are combined to facilitate their application on the places to be treated. This support can be solid (clays, natural or synthetic silicates, silica, resins, waxes, etc.) or liquid (generally water). According to a preferred variant, the nature and the dose of the surfactant (s) are chosen such that the wettability time of the solid composition is between 10 seconds and 3 minutes, preferably between 10 and 50 seconds, and the rate of suspensibility is greater than 50%, preferably 70%. The following definitions are used for the expressions "wettability time". and "suspensibility rate".

The wettability time is measured according to the MT 53.3.1 technique described in the CIPAC HANDBOOK, volume 1 pages 966-967, published by GR Raw in 1970. It essentially consists in measuring the wetting time of 5 g of solid composition out of 100 ml of water. The rate of suspensibility is measured according to the MT 15.1 note 4 technique described in the CIPAC HANDBOOK, volume 1 pages 861-865. It essentially consists in pouring 2.5 g of solid composition into a 250 ml test tube containing 250 ml of hard water, turning the test tube and its contents 30 times, leaving to stand for 30 min and measuring the mass of material contained in the lower 25 ml (10% of the volume of the test piece) of the test piece; the rate of suspensibility is then expressed by the percentage of matter remaining in suspension in the upper 90% of the test piece.

To obtain the solid composition according to the invention, the particles are intimately mixed in appropriate mixers with the additional substances. This gives sprayable powders whose wettability and suspension are advantageous and which can be suspended with water at any desired concentration to prepare the liquid intended to be sprayed. The plasticizing agents are preferably used for the preparation of the compositions according to the invention in the form of granules. In this case, the amount of plasticizer is advantageously greater than or equal to 10% by weight relative to the total weight of the composition, preferably greater than approximately 20% by weight, more preferably between 20 and 50% by weight.

Among the usual plasticizers, mention may be made of all the plasticizers known as plasticizers for cellulose acetate, in particular those described in [reference to be completed], and more particularly polyol esters such as glycerol triacetate (triacetin) or diacetate of triethylene glycol, or esters of hydroxy carboxylic acids such as esters of citric acid or phthalic acid.

According to a preferred embodiment of the invention, the 1-arylpyrazole derivative is distributed homogeneously in the insoluble cellulose derivative, more preferably in the form of a solid solution.

According to the present invention, the term "solid solution" means a homogeneous molecular distribution of the 1-arylpyrazole derivative in the cellulose derivative.

More preferably, the solid solution does not substantially comprise crystals of the 1-arylpyrazole derivative during observation under the scanning electron microscope of the solid composition or of a fraction or a section of this composition, at magnification. of 30,000. Advantageously, the solid composition according to the invention does not contain substantially pores. By the expression “does not contain substantially pores”, it is understood according to the invention that the pores present in the solid composition according to the invention have a diameter of less than about 10 nanometers, preferably less than 2 nanometers. Such a characteristic can also be observed by means of a scanning electron microscope. Due to the absence of pores, the 1-arylpyrazole derivative is not present in the pores but mixed uniformly with the insoluble cellulose derivative. This particularly advantageous property makes it possible to avoid the risks associated with direct contact of the user's skin with the insecticidal compound. The present invention also relates to a process for the preparation of the compositions according to the invention, said process consisting in mixing the cellulose derivative and the 1-arylpyrazole derivatives, alone or optionally in the presence of a suitable solvent or additive and then to give them the final form appropriate to the use that will be made of it. According to a preferred embodiment of the invention, a fusion of the insoluble cellulose derivative and the 1-arylpyrazole derivatives is carried out, alone or optionally in the presence of a solvent or ^a suitable additive, in particular for the preparation of compositions wherein the derivative of 1 -arylpyrazole is distributed homogeneously in the insoluble cellulose derivative.

For the preparation of fibers, the 1 -arylpyrazole is incorporated into the fibers by mixing the product in solution in a first organic solvent suitable for solubilizing the derivatives of 1 -arylpyrazoles, with a solution of the cellulose derivative in a second organic solvent suitable for dissolve the cellulose derivatives, the first and second organic solvents being compatible and preferably identical. The mixture is then extruded through an appropriate die, generally metallic, and solidified by evaporation of the solvent (s). The fiber thus prepared is then cut into fragments to the desired size. The suitable solvent is advantageously acetone.

The particles according to the invention can be prepared according to a similar process by dissolving the 1-arylpyrazole derivative and the cellulose derivative in an appropriate solvent, advantageously acetone, then by spraying said solution, and drying. A suitable device for this purpose is, in particular, an atomizer equipped with a multi-fluid nozzle, in which the organic solution is sprayed with air at a pressure between 2 and 8 bar, preferably between 4 and 6 bar , the spraying being carried out in the presence of a stream of drying air brought to a temperature between 80 and 160 ° C, preferably between 90 and 110 ° C, at a flow rate between 30 and 150 m ³ normal per hour .

The granules according to the invention are advantageously prepared by coextrusion. the cellulose derivative, the derivative of 1 -arylpyrazole and optionally sets introduced plasticizer or premixed and then introduced into a feed hopper ^of an extruder, the molten mixture is extruded through a suitable die to obtain the diameter noodles which are then cut to the desired length.

The present invention finally relates to a method of combating insects, preferably against termites, characterized in that an effective dose of at least one 1-arylpyrazole derivative is applied in the form of a composition as defined previously, in a place frequented or likely to be frequented by the said insects.

The composition according to the invention is particularly suitable for the fight against termites. The effective dose applied depends on the nature of the soil or the building material, and on the desired persistence of action. This dose is generally between 0.05 mg / m ² and 5 g / m ² , preferably between 0.1 mg / m ² and 0.5 g / m ² .

The composition in the form of particles can be applied by spraying or - iσ -

by injection on or in the place to be treated. The volume of the spray or injection liquid is generally between 1 and 5 1 / m ² .

The composition in the form of a sheet is advantageously used to protect the foundations of buildings against termites, the sheet being deposited on the ground before the foundations are made. When the tablecloth is used to border the hollows of building foundations, the strips are advantageously arranged in parallel to one another with overlapping of each other over the required length. An important advantage of the sheet according to the invention is that its effectiveness is maintained even when the strips do not overlap completely, and even if they include a substantial number of cuts, holes or tears.

The following examples are given purely by way of illustration of the present invention and should in no way be interpreted as limiting the scope. In these examples, the compound of formula (I) used is: l- [2,6-Cl ₂ 4-CF ₃ phenyl] 3-CN 4- [SO-CF ₃ ] 5-NH ₂ pyrazole, also called fipronil . It is understood that the same examples can be carried out with other derivatives of 1 -arylpyrazole. The percentages are weight percentages.

Example I: Tablecloth to protect the foundations of buildings against termites

Example 1.1

Cellulose acetate and fipronil are dissolved in acetone, so as to obtain a spinning solution containing (percentage by weight): cellulose acetate: 30% fipronil: 1% acetone: 69%

This solution is extruded through a suitable die into an area where a current of hot air circulates where a filament is formed by evaporation of the solvent. This continuous filament, of circular section, is cut into fragments 18 mm long. These fragments have a diameter of approximately 80 μm and a linear weight of 15 decitex. Sections of these fragments are examined by scanning electron microscopy with a magnification of 30,000: no pores or fipronil crystals are observed. The fipronil content of the fiber is around 3%.

The above fragments are mixed with polyvinyl alcohol fibers 2 mm in length as a binder, in an amount of 10% by weight of polyvinyl alcohol. This mixture is processed by agglomeration using a paper-making machine Η

conventional. The nonwoven web obtained with the appearance of paper has a thickness of 2 mm, a weight per unit area equal to 150 g / m ² , and a fipronil content of approximately 3 g / m ² . The air permeability of this nonwoven web is 2000 1. s "'. Nr ² .

A 30 mm disc of this nonwoven tablecloth is placed on a horizontal wooden board and used to close the open end of a vertical cylindrical chamber with a length of 110 mm and an internal diameter of 25 mm. This chamber is filled to two thirds of its height with ordinary sand. 50 termites of the species Reticulitermes santonensis are introduced into the upper third of the chamber. The sand is maintained at a constant rate of humidity during the test, by daily introducing water (1 volume of water for 4 volumes of sand). The nonwoven disc is sealed in the vertical chamber using an appropriate adhesive, non-toxic to termites. After 4 days, a mortality rate of 100% is observed. The mortality rate observed on a control device with the same disc without fipronil is 0%. This test demonstrates the excellent effectiveness of the sheets according to the invention against termites.

Example 1.2

The test of Example 1.1 is reproduced by introducing termites of the species Heterotermes indicola in place of Reticulitermes santonensis. After 5 days, the same results are observed as for Example 1.1.

Example 1.3

Example 1.1 is reproduced with a 30 mm disc, which includes a 1 cm hole in its center, in parallel with a 30 mm disc without holes, for sheets which have fipronil contents of 0.5 g. / m ² , 3 g / m ² and 6 g / m ² . The effectiveness of these discs, measured in number of days necessary to observe a mortality rate of 100% is reported in the Table below.

These results demonstrate that the effectiveness of the sheet according to the invention is preserved even when it is perforated.

Example 1.4 Four 30 mm discs of cellulose acetate fibers with a fipronil content of 0, 0.5, 3 and 6 g / m ² are obtained by the process of Example 1.1. These four discs are used in test devices comparable to that described in Example 1.1. Each disc is placed on a horizontal wooden table A. A second horizontal wooden board B, 1 cm thick, is placed on the disc and a vertical cylindrical chamber as in Example 1.1, is fixed on wooden board B so that the disc and the vertical chamber are co- axial

The test of Example 1.1 is repeated by introducing 250 termites into each of the four test devices. The following results are seen after 3 weeks.

For the disc without fipronil: the mortality rate is 0%; in addition, table B is pierced by termites, a hole of 1 cm in diameter is observed on the disc, as well as signs of attacks by termites in table A .. For the disc with a fipronil content of 0.5 g / m ² : The mortality rate is 98%; table B is pierced, as is the disc with a 3 mm diameter hole, but table A shows no sign of termite attack. For the disc with a fipronil content of 3 g / m ² : the mortality rate is 100%; Table B is drilled as is the disc with a 1 mm diameter hole, but Table A shows no signs of termite attack. For discs with a fipronil content of 6 g / m ² : the mortality rate is 100%; table B is not pierced by termites and the disc like table A born shows no signs of attack by termites.

Example 1.5

Example 1.1 is reproduced with three nonwoven webs containing fipronil at contents of 0.5, 3 and 6 g / m ² . The discs are previously kept for 3 weeks in non-sterile soil, with an atmosphere of 80% relative humidity and at a temperature of 30 ° C. After 6 days, there is a mortality rate of

100% for the three layers.

This test shows that the sheets according to the invention retain their effectiveness even when they are buried in the ground for a certain time.

Example II: Tablecloth for seedling box

Example II.1

A cellulose acetate is used, the degree of acetylation of which is 2.5, which is dissolved with fipronil in acetone, so as to obtain a spinning solution containing (percentage by weight): cellulose acetate: 33 % fipronil: 2% acetone: 65%

This viscous solution is extruded through an appropriate die into an area where a current of hot air circulates where a filament is formed by evaporation of the solvent. This continuous filament, of circular section, is cut into 12 mm fragments. These fragments have a diameter of approximately 80 μm and a linear weight of 15 decitex. Sections of these fragments are examined by scanning electron microscopy with a magnification of 30,000: no pores or fipronil crystals are observed. The fipronil content of the fiber is 6%. The preceding fragments are mixed with polyvinyl alcohol in the form of fibers 2 mm in length, at a rate of 10 g of polyvinyl alcohol per 100 g of cellulose acetate with fipronil. This mixture is treated by agglomeration using a paper-making machine. The nonwoven sheet obtained has the appearance of paper, has a thickness of 1.5 mm, a weight per unit area equal to 55 g / m ² , and contains an amount of fipronil of approximately 3 g / m ^2. biodegradability rate after 6 months is greater than 80%.

Example II.2: Effect of the application in a sowing box of the nonwoven of Example 1 on the protection of rice in submerged rice fields against the leafhopper (Nilaparvata lugens) and the leaf reel (Cnaphalacrosis medicalis)

We cut from the tablecloth prepared according to Example II.l, rectangles of 28 by 58 cm. The bottom of sowing boxes (28 x 58 cm interior dimensions) and 3 cm high is lined with 37 g / m ² density paper on which a first 2 cm layer of soil is spread. height. The rectangular sheet according to the invention, previously cut, is placed on this layer. 250 g of rice grains (Koshihikari variety) are then sown, then a second layer of soil 1 cm high is placed to cover the grains. Each seedling box thus prepared contains 0.5 g of fipronil. The seed boxes are then placed for 3 days in an enclosure at a temperature of 30 ° C and a relative humidity of 100%. We observe. 3 days after sowing, a root-up rate substantially equal to 0%. The seed boxes are then placed in the greenhouse for 11 days, at an average temperature of 20 ° C, and a relative humidity of 60%. Fourteen days after sowing, the rice seedlings are transplanted into a submerged paddy field. Thirty-nine days after transplanting, 2 whole rice plants are removed from the rice field, which are introduced into a test tube at the bottom of which has been placed a cotton pad soaked in water. The infestation is then carried out by introducing into the said test tube 10 insect pests known under the English term "brown planthopper", also under the Latin name Nilaparvata lugens, or in French "leafhopper". Three days after the infestation, we count the number of dead insects which we divide by the number of insects introduced and we obtain a mortality rate of 74%. Also thirty-nine days after transplanting, 2 sheets of rice plants are taken from the rice field, which are placed in a Petri dish. The infestation is then carried out by introducing into the so-called Petri dish 5 larvae of insect pests known under the English term "rice leaffolder", in Latin Cnaphalacrosis - Î4 -

medicalis. or in French "enrouleuse des feuilles". Five days after the infestation, count the number of dead larvae which is divided by the total number of introduced larvae and a mortality rate of 62% is obtained. This example shows that the tablecloth according to the invention applied conveniently at the time of sowing does not harm the germination of the seeds and moreover provides rice plants, more than a month after transplanting in submerged paddy fields, good protection against insects harmful. Example II.3

The procedure of Example I 1 is repeated, by preparing a fiber containing 13% by weight of fipronil, by cutting fiber fragments with a length of 6 mm, and by preparing a nonwoven web of weight per unit of area equal to 25 g / m ² . This sheet has a thickness of 1 mm and contains approximately 3 g / m ² of fipronil. Its biodegradability rate after 6 months is also greater than 80%.

Example II.4: Laboratory study of the root-up of rice grains sown on the tablecloths prepared according to examples II.l and II.3 For the purpose of this laboratory study, micro-boxes of specific sowing are used , dimensions 11 by 16 cm and height 3 cm. Such sowing boxes are not usually used under practical conditions by rice growers. A non-woven sheet prepared according to Example II.l, and a non-woven sheet prepared according to Example II.3 is applied in a similar manner to that described in Example II.2 in each of these two micro-boxes. . 400 grains

(i.e. 13.3 g) of rice grains (Koshihikari variety) are sown in each case. Such a sowing density is about half that of what is usually practiced by farmers, and generally results in a greater root-up phenomenon. In both cases, the height of the lower soil layer, located under the nonwoven web, is 2 cm, and the height of the upper soil layer, covering the seeds, is 0.8 cm.

This height of the surface layer, less than the minimum height of 1 cm generally recommended, is usually a factor aggravating the phenomenon of root-up.

These 2 sowing boxes are placed for 3 days in an enclosure at a temperature of 28 ° C and with a relative humidity of 100%). 3 days after sowing, we measure by estimation the number of grains of rice that gave rise to the root-up phenomenon, that is to say the number of seeds which, because of the growth of their root, were raised above the top soil layer, which number is divided by the number of seeds sown, to get a root-up rate. We thus obtain for the prepared tablecloth:

- according to Example II.1, a root-up rate of 9%; and - according to example II.3, a root-up rate of 4%.

Example II.4 shows that, even under severe application conditions, in the sense that they normally favor a high root-up rate, the layers according to the invention give rise to a root-up rate which is acceptable to the rice farmer.

Example III: Microparticles

Example III.1

Cellulose acetate is used having a degree of polymerization of between 150 and 220 and a degree of acetylation of between 2.2 and 2.5. Cellulose acetate is dissolved with fipronil in acetone, with stirring, to obtain a solution containing: cellulose acetate 10% fipronil 1% acetone 89% This solution is filtered through a non-woven sieve with an upper mesh opening at

5 μm. Then it is directed to an atomizer, at a flow rate of 1 1 / hour, in which it is sprayed at room temperature, by means of a 2.4 mm diameter bi-fluid nozzle, in the presence of air brought to a flow rate of 100 m ³ normal per hour and at a pressure of 5 bars. The product obtained is then dried with air brought to a temperature of 100 ° C. Cellulose acetate microparticles having 10% by weight of fipronil are obtained, of substantially spherical shape, of size between 1 μm and 50 μm, preferably between 5 and 20 μm.

It does not appear during observation with a scanning electron microscope, at 30,000 magnification, any crystal. It is deduced therefrom that the compound is in solid solution in cellulose acetate. A sample of the microparticles obtained, prepared according to the procedure described in the description, is observed by environmental scanning electron microscopy, at a magnification of 1000. It can be seen that the microparticles are hollow and have the shape of a shell with a thickness of between 0.5 and 1.5 μm. These microparticles have a substantially spherical shape, more or less flattened, and have folds or folds on their surface.

Observation of the microparticles with a scanning electron microscope does not reveal pores, or at least a pore size less than 2 nanometers. due to the magnification used. Example III.2 Example III.1 is repeated, using an organic acetone solution containing: - 15 -

cellulose acetate 10% fipronil 0.1% acetone 89.9%

Cellulose acetate microparticles having 1% by weight of fipronil and the same shape and structure characteristics are obtained. Example III.3

Example III.1 is repeated, using an organic acetone solution containing: cellulose acetate 10% fipronil 0.01% acetone 89.99%

Cellulose acetate microparticles having 0.1% by weight of fipronil and the same shape and structure characteristics are obtained. Example III.4 The microparticles prepared according to Example 1 are mixed with the following powdery ingredients, in the proportions indicated: sodium alkyl naphthalene sulfonate: 2% sodium polynaphthalene sulfonate 10% microparticles prepared according to Example 1 88% Obtained a product having the appearance of a powder whose wettability is?. and the suspensibility rate greater than 50%, thus lending itself perfectly to mixing with water and spraying. Example III.5

A vertically arranged glass tube is used, the diameter of which is approximately 2 cm, the height of 15 cm, and the thickness 2 mm, closed at its 2 ends with aluminum foil. In this tube, we place, starting from the bottom:

- on a height of 5 cm a mixture of thin wooden sticks and paper strips, in which are installed 80 worker termites and 1 soldier termite of the species Reticulitermes santonensis, then - an agar separator layer of about 3 cm in height; then

- a layer of sand 5 cm high treated (or not treated for the control) with a certain amount of one of the samples of microparticles prepared according to one of examples 1 to 3; then

- an agar separating layer about 1 cm high; then - a layer of thin strips of paper 1 cm high, which is a target food source for termites. The samples of microparticles tested are those with 10% and 0.1% fipronil, described in Examples III.1 and III.3 respectively. The entire contents of the tube are regularly rewetted during the duration of the test. The treatment of the sand layer is carried out by incorporating a determined quantity of microparticles according to the invention, in an equally determined volume of sand, then homogenization of the assembly before taking the sample placed in the glass tube. We thus have the quantity or dose of microparticles applied by volume of sand expressed by weight of fipronil (in mg) per cm ³ of soil. This volume dose. taking into account the practical methods of application by specialists, is also expressed in weight per unit of surface treated, (or surface dose) considering that the product penetrates under the conditions of practice on 5 cm of soil. The doses thus applied are indicated in the table below. For the duration of the test, the entire device is kept in the dark, except at the time of the readings, and at room temperature. The readings are taken 1, 2, 3, 4, 7 days after the start of the test, counting on the number of visible termites, the number of dead termites and the number of living ones. We calculate the mortality rate equal to the number of dead termites divided by the total number of visible termites. In the case of the control device (with untreated layer of sand), the termites explore the layer of sand over its entire height (5 cm penetration, clearly visible galleries), up to the target food layer. Up to 5 days after the start of the test, the observed mortality rate is 0%.

The results in the case of treatment are shown in the table below. In this table, the penetration corresponds to the height traveled in the layer of sand treated, 7 days after the start of the test, by termites (maximum length of the galleries observed).

Mortality results show excellent efficacy of the compositions according to the invention. Furthermore, the treated sand layer is. for all the doses tested, free of visible galleries + over its entire height. In other words, the layer thus treated constitutes an impassable barrier.

Example IV: Granules

Example IV.1: Preparation of the granules

For the preparation of the granules according to the invention, a laboratory twin-screw extruder is used, separated into 15 individual zones. The screws have a diameter of 25 mm and a length of 48 cm. The temperature of the different zones is as follows: - zone 1 30 ° C

- zones 2 and 3 110 ° C

- zone 4 150 ° C

- zones 5 to 1 1 180 ° C - zones 12 to 15 190 ° C. The extruder rotates at a speed of 150 revolutions / minute to obtain a homogeneous melt, which is extruded through a circular nozzle to form a rod allowing the formation by means of a granulator of granules of 1 mm in length and 1 mm in diameter. The yield of the extruder is 4 kg / h of granules. Cellulose acetate having a degree of polymerization of 220 and an degree of acetylation of 2.5 is used.

The plasticizer is triacetin.

The cellulose acetate is introduced into the first zone of the extruder, the plasticizer in the second zone of the extruder in a proportion by weight of 1 relative to the weight of the cellulose acetate, and the fipronil in the third. area of the extradeuse in a proportion of 5% by weight.

Granules are obtained comprising by weight 47.5% of cellulose acetate. 47.5% plasticizer (triacetin) and 5% fipronil. Example IV.2: Analysis of the granules Four samples of granules containing respectively 0%, 0.1%, 1% and 5% by weight of fipronil obtained by the process according to example IV.1 were examined by scanning electron microscopy in strictly comparative conditions. 1 Observation methods Random selection of samples. A continuous uniform layer of the granules to be studied is first deposited on a smooth non-hard surface (sheet of cardboard) which allows to exert a slight pressure on the granules without deforming them.

For ^observation to the native state, a scanning object holders standard microscopy is covered with double-sided tape whose protection is removed. The adhesive is brought into contact with the bed of granules and 20 to 30 granules are retained on the sticky surface. This sample is kept dry until the metallization step

For the observation of the internal structure, the granules are collected on a plastic support constituted by the leveled surface of an inclusion capsule for ultramicro tomie filled with polymerized epoxy resin, by means of a drop of glue. cyanoacryhque (which takes almost instantaneously) spread over the surface.

Cutting technique

The samples intended for the examination of the internal structure are cut on an ultramicrotome equipped with a diamond knife and the smooth surfaces thus released immediately undergo metallization. Metallization

The samples, whether or not cut, are transferred to a sputtering apparatus and receive a layer of gold of approximately 10 nm thick, under a rarefied atmosphere of argon. They are then kept in a desiccator until the time of observation. Observation

The preparations are observed under an acceleration of 10 KV using a Hitachi S800 electron microscope equipped with a field emission gun whose theoretical resolution is better than 2nm.

3 Results External surfaces and original cut faces (whole granules)

The granules have the shape of a short cylinder whose diameter is roughly equal to the height. Thanks to the random collection mode and the roughly isodimensional shape of the granules, these can be found fixed either laterally or by their end, which allows observation of both the cylindrical lateral surface and the sections. Observations are made in a range of magnifications between 60 and 5000.

All the granules have the same general appearance linked to the extrusion mode: the lateral faces are relatively smooth, with traces left by the die while the ends are partially cut transversely and partially broken. The control granules have the appearance of a solidified amorphous material, with a more or less flaky break, fairly characteristic of hard plastics. Any crystal texture is not visible on any of the observed faces and no trace of heterogeneity can be seen even at the highest magnifications.

The granules with 0.1, 1, and 5% of active material cannot be distinguished from the control granule with 0%. No trace of texture or heterogeneity appears. even magnified 5000 times. The addition of the active ingredient does not in any way modify the microscopic appearance of the granules.

Granules cut in the microtome (fresh sections)

The fresh sections made on the control granules and with a concentration less than or equal to 5% do not show any differences. A perfectly smooth surface is observed in all cases.

4 Comments and conclusion

Observations made with different concentrations of Fipronil in the cellulose acetate matrix show that the addition of the active ingredient does not in any way modify the texture of the granules and that no form of crystallization is visible up to an equal concentration. at 5 %.

The active ingredient can be considered as being in the dissolved state in the cellulose acetate matrix, considered in turn as a solvent of “infinite” viscosity. A real solid solution of fipronil in cellulose acetate is therefore obtained.

Claims

- 2 ~ 1 - CLAIMS

1. Solid composition of a water-insoluble cellulose derivative characterized in that it comprises an effective amount of at least one derivative of 1 - arylpyrazole.

2. Composition according to claim 1, characterized in that the 1 -arylpyrazole derivative is a compound of general formula (I)

wherein, Ri is a halogen atom or a CN or methyl group;

R ₂ is S (O) _n R ₃ ;

R ₃ is an alkyl or haloalkyl radical;

R4 represents a hydrogen or halogen atom; an alkyl, haloalkyl radical NR ₅ R6, -S (O) _m R ₇ , C (O) R ₇ , -C (O) OR ₇ , -N = C (R ₉ ) (Rι ₀ ) or -OR ₈ , R ₅ and Rg represent, independently of one another, a hydrogen atom, an alkyl, haloalkyl, -C (O) alkyl, -S (O) _r CF ₃ radical; or R5 and R ^ may together form a divalent alkylene radical which may be interrupted by one or two divalent heteroatoms, such as oxygen or sulfur; R ₇ represents an alkyl or haloalkyl radical; Rg represents an alkyl, haloalkyl radical or a hydrogen atom;

R ₉ represents an alkyl radical or a hydrogen atom; Rio represents a phenyl or heteroaryl group optionally substituted by one or more halogen atoms or groups such as OH, -O-alkyl, -S-alkyl, cyano, or alkyl; X represents a tri valent nitrogen atom or a C-Rι ₂ radical, the other three valences of the carbon atom being part of the aromatic cycle; Ruet R _i2 represent, independently of one another, a hydrogen or halogen atom; Ri 3 represents a halogen atom or a haloalkyl, haloalkoxy group, -S (O) _q CF ₃ or -SF ₅ ; m, n, q, r represent, independently of one another, an integer equal to 0, 1 or 2; with the proviso that, when Ri is methyl, then R3 is a haloalkyl group, R4 is NH, Ru is Cl, Rι ₃ is CF ₃ , and X is N.

3. Composition according to claim 2, characterized in that R _j is CN, and or R3 is a haloalkyl radical, and / or R4 is NH, and / or Ru and R ι are independently of each other an atom of halogen, and / or Rj ₃ is a haloalkyl radical.

4. Composition according to one of claims 1 to 3, characterized in that the derivative of 1 -arylpyrazole is fipronil.

5. Composition according to one of claims 1 to 4, characterized in that the insoluble cellulose derivative is an aliphatic ester of cellulose, preferably a cellulose acetate.

6. Composition according to claim 5, characterized in that the insoluble cellulose derivative is a cellulose acetate whose degree of polymerization is between 150 and 250 units, preferably between 150 and 220.

7. Composition according to one of claims 5 or 6, characterized in that the cellulose acetate has a degree of acetylation of between 1.2 and 2.8, preferably between 1.9 and 2.5.

8. Composition according to one of claims 1 to 7, characterized in that the effective amount of 1-arylpyrazole derivative is between 0.0001 and 50% by weight, preferably between 0.05 and 25% by weight.

9. Composition according to one of claims 1 to 8, characterized in that it is in the form of fibers.

10. Composition according to claim 9, characterized in that the effective amount of 1 -arylpyrazole derivative is between 0.1 and 15% by weight.

1 1. Composition according to one of claims 1 to 8, characterized in that it is in the form of a woven or nonwoven web obtained with the fibers according to claims 9 or 10.

12. Composition according to claim 11, characterized in that the effective amount of 1-arylpyrazole derivative is between 0.01 and 25 g / m ^, advantageously between 0.1 and 10 g / m ^, or even for certain uses between 1 and 5 g / m ^.

13. Composition according to one of claims 11 or 12, characterized in that it further comprises a binder, the weight ratio binder / fibers comprising the derivative of 1 arylpyrazole being between 1 and 20%, preferably between 5 and 15%.

14. Composition according to one of claims 1 to 8, characterized in that it is in the form of particles.

15. Composition according to claim 14, characterized in that the effective amount of 1 -arylpyrazole derivative is between 0.05 and 10% by weight.

16. Composition according to one of claims 13 or 14, characterized in that the particles are microparticles of substantially spherical shape and of a size between approximately 0.3 and approximately 200 μm, preferably between 1 and 50 μm, even more preferably between 5 and 20 μm.

17. Composition according to Claim 16, characterized in that the microparticles are hollow and are in the form of an envelope or shell with a thickness between 0.1 and 3 μm, preferably between 0.5 and 1.5 μm.

18. Composition according to one of claims 13 to 17, characterized in that it further comprises surfactants and / or diluents.

19. Composition according to one of claims 1 to 8, characterized in that it is in the form of granules.

20. Composition according to claim 19, characterized in that the effective amount of 1-arylpyrazole derivative is less than about 10% by weight, preferably less than 7% by weight, more preferably between 0.05 and 5% by weight.

21. Composition according to one of claims 19 or 20, characterized in that the granules have a length of between approximately 0.5 and 2 mm, preferably of approximately 1 mm, and an average diameter of between approximately 0.5 and 2 mm, preferably about 1 mm.

22. Composition according to one of claims 19 to 21, characterized in that it further comprises a plasticizing agent.

23. Composition according to claim 22, characterized in that the amount of plasticizer greater than or equal to 10% by weight relative to the total weight of the composition, preferably greater than approximately 20% by weight, more preferably between 20 and 50 % in weight.

24. Composition according to one of claims 1 to 8, characterized in that it is in the form of powder.

25. Composition according to one of claims 1 to 24, characterized in that the 1-arylpyrazole derivative is distributed homogeneously in the insoluble cellulose derivative.

26. Composition according to claim 25. characterized in that it is in the form of a solid solution.

27. Composition according to one of claims 25 or 26, characterized in that it does not contain substantially pores.

28. Process for the preparation of the compositions according to one of claims 1 to 27, characterized in that the insoluble cellulose and the derivatives of 1- arylpyrazoles are mixed, alone or optionally in the presence of a solvent or an additive appropriate, then they are given the final form appropriate to the use to which it will be put.

29. Process according to claim 28, characterized in that a fusion of the insoluble cellulose derivative and the 1-arylpyrazole derivatives is carried out, alone or optionally in the presence of a suitable solvent or additive.

30. A method of combating harmful insects, characterized in that an effective dose of at least one 1-arylpyrazole derivative is applied in the form of a composition according to one of claims 1 to 27, in one place frequented or likely to be frequented by said insects.

31. Method according to claim 30, characterized in that the harmful insects are termites.