NZ228265A

NZ228265A - Insecticidal formulation comprising liquid co 2 and a cosolvent as carrier, and it being pressurised by nitrogen gas

Info

Publication number: NZ228265A
Application number: NZ228265A
Authority: NZ
Inventors: Jean-Louis Pean; Jean-Luc Mizandjian
Original assignee: Air Liquide
Priority date: 1988-03-10
Filing date: 1989-03-08
Publication date: 1990-09-26
Also published as: ES2010434A6; AU610369B2; JPH03500174A; KR900700006A; BR8906376A; DE68912463D1; WO1989008391A1; EP0357741A1; ZA891740B; EP0357741B1; AR244937A1; CA1311191C; FR2628294B1; FR2628294A1; AU3213289A

Description

<div id="description" class="application article clearfix"> 22 8 2 6 5 Priority Date(s); .. ....... Complete Specification Fiied^. Class: . ftp.1. hYfS/o^.ob; Puw'ication Data''!i»??» P.O. Journal, Nov , ...JSSfe; No.: Date: NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION HPACKED INSECTICIDE MIXTURES AND INSECTICIDE TREATMENT PROCESS" I/We, L'AIR LIQUIDE, SOCIETE ANONYME POUR L1 ETUDE ET L'EXPLOITATION DES PROCEDES GEORGES CLAUDE, 75 quai d'Orsay 75321, Paris, Cedex 07, France, a French company hereby declare the invention for which I / we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - - 1 - (followed by page la) 22 8 2 6 5 - 14- PACKED INSECTICIDE MIXTURES AND INSECTICIDE TREATMENT PROCESS The present invention relates to packed insecticide mixtures and preventive and curative treatment processes. The combat against the presence of insects has for purpose to avoid the degradation of plants and food products when they are being produced, transferred, stored, and to ensure the maintenance of the hygiene of the sanitary or growing premises. The insecticides are employed in accordance with various techniques. The ULV (ultra low volume) methods employ electric appliances which fractionate the insecticide solution under the effect of centrifugal force on the periphery of a rapidly rotating disk. The atomization technique consists in putting the insecticide in solution in an aqueous phase and spraying the mixture by pressurizing in a pump and passage through a nozzle. The insecticide is in this way diffused in a surrounding atmosphere onto the plants and walls of the infested places in the form of droplets of a diameter greater than or equal to 200 micrometers. The relatively large size of the drops obtained limits the effectiveness of the treatment owing to the presence of nontreated zones and stratification, and the use of pumps for pressurizing the insecticide gives rise to frequent problems of clogging. This technique is less and less in use. Insecticides ready to use may be employed in solution in 228265 - 2 - organic solvents according to the nebulization technique. This technique consists in dispersing droplets of about 50 micrometers in the atmosphere by injection with compressed air in specially designed nozzles. This treatment requires the use of an air compressor and the weight of the particles obtained often results in a poor homogenization of the insecticide in the surrounding air and on the treated surfaces. The insecticide treatment for the protection of plant and food products and for maintaining the hygiene of the premises requires the use of a ready-to-use insecticide, a homogeneous diffusion of the product in the atmosphere and effective treatment of all the surfaces and a simple and even automated operation. Insecticide mixtures packed under pressure have been found which permit a preventive or curative treatment of various agricultural and industrial premises under excellent conditions of effectiveness. These insecticide mixtures packed under pressure are constituted by the insecticide product in the form dissolved in liquid carbon dioxide and a cosolvent maintained at the ambient temperature under pressure equal to at least the vapour pressure of the carbon dioxide, namely 5.8 MPa to 20 Megapascals (MPa). The insecticide mixtures are preferably packed under a pressure of between 8 and 20 MPa by pressurization with gaseous nitrogen. 22 8 2 65 - 3 - The carbon dioxide is employed as a solvent agent and a propellant of the mixture: insecticide product-cosolvent. The pressurization with gaseous nitrogen permits an improved purging of thedistribution pipes and avoids the formation of carbon dioxide ice. It has furthermore been found that the pressurization with gaseous N2 ensures a homogeneous injection of the insecticide mixture by a more regular rate of flow. As an example, the relative variation of the withdrawing rate of flow from a storage cylinder is 25% with C02 at 60 bars, 20°C whereas it is only 5% with CO^ pressurized with gaseous nitrogen at 100 bars, 20°C. The addition of nitrogen also results in a dissolving of this gas in a liquid CO ^ and the atomization - expansion of the mixture to atmospheric pressure - generally finer droplets than with CO ^alone since they are fractionated by the desoption of the initially dissolved nitrogen. Depending on the chemical nature of the insecticide product, one third or the cosolvent may be chosen from a large number of compounds, such as paraffin, naphthene, olefin, aromatic compound, chlorinated hydrocarbon, and deodorized petroleum. Methylene chloride and deodorized petroleum are excellent cosolvents. There will preferably be used a deodorized petroleum, a mixutre of C8 to C11 hydrocarbons having a boiling point at atmospheric pressure of 100 to 150°C. The insecticide product may be chosen from known, currently employed, insecticides, natural pyrethines, 22 8 2 - 4 - synthetic pyrethrinoids or from among phosphorated organos. There will preferably be employed a synthetic pyrethrine such as deltamethrine or bioresmethrine. In this particular case, the contents by weight of the compounds of the aerosol of the insecticide mixture may between 0.01 and 3% for the pyrethrinoids, 1 to 30% for the cosolvent, the complement made up to 100 by carbon dioxide and nitrogen to obtain a pressurization of 5.8 to 20 MPa for a maximum temperature of 50°C. The use of a synergizing agent up to a content by weight of 30% may be advantageous. In order to reinforce the insecticide power of the product a synergizing agent may be added in the mixture, preferably piperonyl butoxide. The insecticide treatment is carried out by an aerosolization technique in which a mixture under pressure is dispersed in the form of fine droplets of from 0.1 to 50 micrometers, through an atomization means. The presence of the liquid carbon dioxide on the upstream side and its vaporization on the downstrean side of atomization means increases the fractionating energy and the size of the drops produced is smaller than that usually obtained with compressed air. The fine atomized droplets follow the convection movements in the treated premises while limiting any stratification. Each reservoir of insecticide mixture is equipped with a plunger tube for drawing off in the liquid phase and feeding a distribution piping. The aerosolization is achieved 22 8 2 6 - 5 - through an atomization system, for example through a nozzle having a whirling effect. The injection system, a non-limitative example of which is shown in Fig. 1 of the accompanying drawing comprises one or more storages (1) of insecticide/carbon dioxide/cosolvent mixture with a plunger tube (2) which feeds a distribution piping (3) through a valve (4), the aerosolization being obtained through one or more nozzles or an atomization system (5). Each treatment is carried out by cycles of injections and the valve (4) can be controlled by a timer (6). The circuit is equipped with safety means, an expansion valve (7) for example. The inside diameter of the injection pipe will be greater than or equal to 4mm so as to avoid pressure drops between the storage and the injection. The atomization system is constituted by one or more nozzles placed on the mixture conducting piping. The diameter of the outlet of the nozzles will be between 0.12 and 0.5 mm so as to obtain a mean size of the droplets of 1 micrometer.There will preferably be employed nozzles having a whirling effect (inclined supply passages of the outlet orifice) and the projection of the product is ensured over a distance of about 10 meters in the form of a solid cone having an apex angle of 5 to 10°. The size of the droplets obtained is on the order of 1 micrometer and permits a homogeneous diffusion of the 22 8 2 - 6 - product in space or on the treated surface. This size, about 10 to 20 times smaller than that obtained by conventional atomization - nebulization treatments, is due to a pressurization of the mixture higher than or equal to 60 bars, 2°C and is accentuated by, upon a complementary pressurization with nitrogen, desorption - fractionating energy of dissolved N issuing from the expansion of the mixture. It has been found that the presence of a dissolved gas, such as nitrogen, in liquid carbon dioxide at a pressure equal to or higher than 8 MPa, avoids during the emptying dropping to a pressure range in which the carbon dioxide is solid, which avoids clogging and bad operation (irregular rate of flow, incomplete restitution of the mixture employed). The insecticide - liquid carbon dioxide - cosolvent mixtures packed under pressure permit a preventive or curative treatment by aerosolization of agricultural, public or industrial premises. There may be mentioned greenhouses, agricultural hangers, silos and grain conveying system, the storage enclosures and the transport of foodstuffs and the sanitary and growing premises. The treatment ensures a knocking down or lethal effect on flying insects (flies, mosquitos, lepidoptera...), crawling insects (ants, cockroaches...) and coleoptera, in particular of stored foodstuffs (rhizopertha, sitophilus, tribolium). 22 8 2 65 - 7 - A driving out and persistent effect is also noted on suports such as sheet metal and building blocks. The process may also be applied to the disinsectization in public hygiene in closed premises (hotels, stores, industries, offices...) or areas in the open air (agricultural areas, farmyards, parkings, sports grounds...). The following examples of disinsectization which are in no way limited are given. Example 1 : In order to disinsectize a greenhouse producing cucumbers divided into transverse rows of plants, 30 kg cylinders filled in accordance with the invention are employed, one cylinder being used for 1,700 cu. m of the treated premises. The geometry of the treated volume is the following: length = 47in, width = 15.75m (5 rows of plants) and height about 2.2m. The cylinder of the insecticide mixture is placed in the centre of the premises to be treated and is "equipped with two injection tubes having a diameter of 4/6 mm and a length of 3 in. Each tube is provided at its end with two nozzles 0.25 mm in diameter located in a horizontal plane at about 1.2 m from the ground. Fed under a pressure of 5.8 MPa with the insecticide mixture each nozzle has a rate of flow of 1 g of mixture per second. Fig. 2 of the accompaning drawing is a schematic of the arrangement, S designates the storage of the insecticide mixture, the 22 8 2 6 - 8 - dotted lines the hedges of plants and the letters A, B, C, D, and E the points at which the insects are counted. The composition of the injected mixture is as follows: Deltamethrine 4.25 g 5 Methylene Chloride (CH2C12 1.68 kg Liquid CO^ 25.32 kg CO^in a gaseous phase 2.0 kg The insecticide treatment lasting 2 hours is followed by •JO an incubation of 24 hours and a counting of the insects at various points of the treated premises, in accordance with Fig. 2. The observed mortality of the bugs is complete whereas there is a great reduction in the aleurodes (white fly). The population of aleurodes is added up on 4 sheets and inserted in Table 1. TABLE 1 Counting Points Before Treatment 24H After Treatmnet 1 5 20 PT A 15 1 PT B 25 4 PT C 15 1 PT D 20 3 PT E 15 4 25 22 8 2 6 - 9 - Example 2; A bottle of mixture packed in accordance with the invention is employed for the disinsectization of an agricultural hanger. This premises has a width of 11 m, a length of 14 m, the height of the sides is 5 m and the height of the central top is 6 in. The total volume is about 750 cu. in. The formulation of the mixture is the following (fractions by weight): - deltamethrine 0.6% - piperonyl butoxide 3 % - deodorized petroleum solvent 27 % (solvens 100) - gaseous CO^ and for a sufficient quantity 15 pressurization to 80 bars The mixture is initially put in condition with liquid CO at a pressure of 60 bars, then pressurized with gaseous nitrogen to 80 bars. The mass of nitrogen introduced for pressurizing the mixture at 60 bars, 20°C to 80 bars is 1 0 20 equal to 10-15% of the mass of CO^employed. For the treatment, there is employed a pressurized cylinder containing 1,667g of mixture in the liquid phase (deltamethrine: 10 g, solvens 100: 450 g, piperonyl butoxide: 50 g and CO : 1,157 g) and 158 g of CO in a 2 2 25 gaseous phase. The compl mentary nitrogen is added in the amount 100-150 g. The dose of insecticide employed is controlled by the 22 8 2 - 10 - duration of the injection at a constant rate of flow. The treating apparatus is installed on a small side of the premises on the central axis. The cylinder of insecticide mixture is equipped with a 5 plunger tube connected with a stainless steel piping having an inside diameter of 4 mm and a length of 10 mm. The piping extends from the cylinder vertically, describes a hairpin bend and redescends to the point of injection placed about one meter from the ground. A nozzle having a whirling 10 effect of the make "LECHLER", type K 212 09511, having an outlet diameter of 0.25 mm is placed at the end of the piping and its supply is remote controlled by an electrically operated valve placed immediately on the downstream side of the nozzle. 15 The injection is effected at a constant rate of flow ( 5%) of 80g of mixture per minute in the form of a solid cone having an apex angle of 5° with a directed jet of 10m; a mist is formed between 10 and 15 m, materializing the terminal zone of the blowing effect. 20 The insecticide dose applied is 1.125 g of synergized deltamethrine, namely 1.5 synergized deltamethrine per 1000 cu. m. It permitted obtaining a mortality of 100% of insects placed at various points of the premises such as shown in Fig. 3: flies, rhizoperta dominica, setophilus 25 granarius, tribolium confusum, ants and lepidoptera. A driving out effect is in particular observed on Setophilus yranarius and Tribolium confusum. 22 8 2 6 11 A persistent effect is moreover observed on a support of the sheet metal, building block type (Table 2) or haricot bean leaves. This table shows the mean of the final effect in % of mortality. It has been found that the vertical and bent position of the injection tube of 10 m did not modify the characteristics of the injection, regularity of the flow, deposit in the piping. TABLE 2 1 0 Mean of final effect (% mortality) Sheet Metal Building block 1 5 S. granarius 71% 75% T. confusum 44% 24% R. Dominica 92% 1 00% </div>

Claims

<div id="claims" class="application article clearfix printTableText"> 22*265;WHAT fy'.'.'C CLAIM ~ 12;1. A packed insecticide mixture constituted by the insecticide product in the form dissolved in liquid carbon dioxide and a cosolvent maintained at ambient;5 temperature at a pressure of 8 to 20 MPa by pressurization with gaseous nitrogen.;2. A packed insecticide mixture according to claim 1, wherein the cosolvent is chosen from among paraffin, naphthene, olefin, aromatic compounds, chlorinated;10 hydrocarbons and deodorized petroleum.;3. A packed insecticide mixture according to claim 2, wherein the cosolvent is methylene chloride.;4. a packed insecticide mixture according to claim 2, wherein the cosolvent is deodorized petroleum, a mixture of C8;15 to C11 hydrocarbons having a boiling point of between 100 and 150°C at atmospheric pressure.;5. A packed insecticide mixture according to any one of claims 1 to 4, wherein the insecticide product belongs to the class of pyrethrinoids, pyrethrins and synthetic;20 pyrethrinoids.;6. A packed insecticide mixture according to any one of claims 1 to 5, wherein the composition by weight is the following: 0.01 to 3% of jgyrethrinoid, 1 to 30% of cosolvent, complement to 100 by carbon dioxide and nitrogen.;25 7., A packed insecticide mixture according to claim 6,;wherein they contain a synergizing agent -^iiatx^duced in a;proportion by weight of at the most 30% by;T £ >v of;the mixture.;!(* '3 AUG 1990 w 228265 -13,- 8. A packed insecticide mixture according to claim J_,— wherein the synergizing agent is piperonyl butoxide. 9. An insecticide treatment employing an insecticide mixture according to any one of the claims 1 to 8, v/herein the treatment is effected by aerosolization in which the insecticide mixture is dispersed in the form of fine droplets through an atomization means. 10. An insecticide treatment, substantially as herein before described v/ith reference to Example 1 or Example 2 of the description. 11. A packed insecticide mixture substantially as herein described with reference to the examples and drawings. OATED THIS 3OJ<>0AY OF A. J, PARK & -SON PER t ahents for theWpu£antf , f </div>