MXPA99005683A - Microemulsion insect control compositions - Google Patents

Abstract

Disclosed herein are microemulsion insecticides that do not contain conventional actives. The microemulsion form permits insects to be killed by an oil/surfactant combination.

Description

COMPOSITIONS OF MICROEMU LSION FOR INSECT CONTROL BACKGROUND OF THE INVENTION The present invention relates to microemulsions capable of killing insects without the use of conventional insecticides. It is particularly useful for killing crawling insects that have hard, waxy exoskeletons. The hydrocarbon solvents assist in tearing down insects. Unfortunately, many hydrocarbons are flammable and, as a result, conventional insect control agents are sometimes delivered via oil / water type emulsions. See, for example, U.S. Patent 5, 145,604. The description of this patent, and of all other publications referred to herein are incorporated by reference, as if fully set forth herein. However, many oil / water emulsions of the prior art are unstable. The user should shake the container shortly before using it to recreate the emulsion on a temporary basis. Consequently, the technique developed much more stable micoremulsions containing water, hydrocarbon, conventional insecticide, and one or more emulsifiers. See, for example, U.S. Patent 5, 037,653. For purposes of this application, a "microemulsion" is a stable, transparent dispersion of oil and water, where the dispersed phase consists mainly of small droplets with diameters between 10 and 1,000 millimicrons. However, because such prior art insecticides contain conventional insecticidal actives, they are subject to severe regulatory control, have a relatively high cost, have limitations in their use (for example, not too close to food), and sometimes they are perceived by the public as environmentally undesirable. Some have tried to apply surfactant solutions directly to insects, as a more natural insecticide approach. See, for example, U.S. Patent 5,489,433. However, this approach is not very effective against hard body insects, such as cockroaches. Thus, there is a need for environmentally safe insect control compositions.

BRIEF DESCRIPTION OF THE INVENTION In one aspect, the invention provides a microemulsion. The total hydrocarbon solvent in the microemulsion is above 20% and below 60% (by weight). If a hydrocarbon impeller is used it is part of the hydrocarbon solvent, and the portion of the hydrocarbon solvent apart from the impeller is preferably between 15% and 35% (by weight) of the global microemulsion. Preferably, the microemulsion is capable of causing "knockdown" of at least 80% of a population of German cockroaches in the "Standard Test" described below, in one minute or less. The surfactant is between 1% and 20% by weight of the microemulsion, and at least 10% by weight of the microemulsion is water (preferably above 30%). Importantly, there is essentially no "Conventional Insecticide Active", as the term is defined below. The above microemulsions are preferably delivered in the form of an aerosol. It is preferred that 5% or more (eg, 10-25%) by weight of the microemulsion is a hydrocarbon promoter dispersed in the microemulsion. A wide variety of gaseous hydrocarbons can be used for this purpose. They usually liquefy under the pressure conditions of an aerosol can and become part of the hydrocarbon solvent. For example, the impeller can be dimethyl ether, difluoroethane, propane, butane, isobutane and mixtures thereof. A particularly preferred impeller is B-70 from Phillips Petroleum, which is a propane / n-butane / isobutane mixture, 55/27/18 (% mol). Another is A-70 from Phillips Petroleum, a 45/55 (% mol) mixture of propane / isobutane. For purposes of this patent, a "hydrocarbon" only has carbon and hydrogen. A wide variety of other hydrocarbon solvents can be used (apart from the impeller). Preferably, these non-driving hydrocarbons have between 6 and 20 carbons. Examples include hexane, benzene, toluene, xylene, mineral spirits, mineral oils, d-limonene, heavy aromatic naphtha, kerosene, paraffins, and other alkanes and alkenes. Exxon / Esso EXXSOL brand hydrocarbons are particularly preferred. Normally these mixtures are hydrocarbons below C20 (alkanes, alkenes). EXXSOL D-95 and EXXSOL D-60 are especially preferred.

The surfactants can be cationic, anionic, amphoteric and nonionic surfactants. However, we prefer to use a mixture of an anionic surfactant and a nonionic surfactant. See generally EP677.579. Especially preferred is an essentially equal mixture of isopropylamine sulfonate (Calimulse PRS, Pilot Chemical) and a tristyrylphenol, such as ethoxylated tristyrylphenol (Soprophor BSU, Rhone Poulenc). Other suitable nonionic surfactants are Soprophors 4D 384 and FL, and dentate polyethoxylates of primary and secondary aliphatic alcohols having from 8 to 24 carbon atoms in the alkyl alcohol chain. In addition, part or all of the ethylene oxide can be replaced by the propylene oxide. Still other suitable nonionic detergents are polyoxyalkylene alkyl phenols; polyalkylene esters of the major organic acids having 8 or more carbon atoms in the acid hydrophobe and 10 or more moles of ethylene oxide as a hydrophilic group; polyalkylene alkyl amines, whose hydrophobic group is from a primary, secondary or tertiary amine and whose ethylene oxide content is sufficiently high to impart both water solubility and non-ionic characteristics, usually derived from fatty acids with 8 or more carbons; polyalkylene alkyl amides having a hydrophobic group derived from an amide of a fatty acid or ester; fatty acid esters of glycols, polyalkylene oxide block copolymer and the like. Alkyl aryl sulfonates of 6 to 20 carbon atoms in the alkyl group are representative of suitable anionic surfactants; C10-C22 fatty acid soaps; C10-C22 fatty sulfates; C.sub.0 -C.sub.22 alkyl sulfonates, including the alkali metal salts of the major alkyl and linear paraffin sulphonic acids and salts thereof; dialkyl sulfosuccinates of alkali metals, ethoxylated alcohol sulphates, phosphate esters, taurates, and the like. See also U.S. Patent 5,037,653 for other surfactants. For purposes of this application, "Conventional Insecticidal Active" shall mean synthetic pyrethroids active as insecticides (eg, cypermethrin, cyfluthrin, lambda-cyhalothrin, aletrin forte, phenanthrin, d-phenatrin, tetramethrin, resmethrin, esbiothrin, allethrin, permethrin, d-trans allethrin and kadetrin), natural pyrethrum (e.g., pyrethrins), organophosphates (e.g., chlorpyrifos), carbamates (e.g., Baygon), and chlorinated hydrocarbons (e.g., methoxy-chloro), and heterocyclic (e.g. , phenyl pyrrole). In order to achieve acceptable performance at relatively low emulsifier levels, co-solvent alcohols can also be used. Preferably, a mixture of primary organic alcohols is added. One can be a primary aliphatic alcohol having a carbon content of between 3 and 12 carbons (e.g., 1-octanol (Alfol 8), 1-hexanol, 1-pentanol, or 1-butanol). The other may be a non-aromatic ether alcohol having less than 20 carbons (for example, diethylene glycol monohexyl ether (hexyl carbitol), diethylene glycol monobutyl ether, or propylene glycol monobutyl ether). In addition, certain glycols can be added, such as hexylene glycol, triethylene glycol or 1,4-butanediol.

When the microemulsion contains a gaseous impeller and is pressurized, the microemulsion can be atomized from an aerosol can. As an alternative, a pump atomization container (without impeller) can be used. The dew is projected, preferably directly on a creeping insect. Because the spray is a microemulsion, it is very stable. In this way, if the aerosol can has been shaken at the factory, a consumer does not need to shake the can before use. The hydrocarbon helps the emulsifier to penetrate the outer shell of the insect. Then the emulsifier is able to break down and thus kill more effectively. The particle size, due to the existence of the microemulsion, it is particularly important to help in the penetration of the shell. Because the hydrocarbon levels are high, the microemulsion has excellent demolition characteristics. Moreover, regardless of the high levels of hydrocarbons, the flammability is acceptably low. Deionized water (eg, 20-50% by weight) is preferred. In addition, other standard additives, such as corrosion inhibitors and fragrances, can be added. A preferred pH range for the microemulsion is between pH 6 and pH 8. Too low a pH can cause corrosion of the can and can also adversely affect the surfaces that are atomized. Too high a pH can adversely affect surfaces that are atomized or may cause consumer uneasiness.

The insects that can kill themselves by means of these microemulsions include cockroaches (for example, the German, the American), ants, lepisma, and other crawling insects. The objectives of the present invention include providing an insecticide: (a) which does not have a Conventional Insecticidal Active; (b) which does not require to be stirred by a consumer before being used; (c) which is effective against crawling insects, such as cockroaches; (d) which is relatively inexpensive to produce; (e) which is suitable to be delivered in the form of an aerosol; and (f) which is suitable for use even near areas where food is present. These and still other objects and advantages of the present invention (e.g., methods for using such microemulsions), will be apparent from the description that follows. The following description is simply of the preferred embodiments. In this way, the claims should be observed in order to understand the full scope of the invention.

DETAILED DESCRIPTION DETAILED Experimental preparations The percentages are percentages by weight. Standard test on crawling insects To test the effectiveness of the compounds A-C (where A and B are compounds of the present invention, where C is a macroemulsion), direct atomization knock-down tests were run. In a set of experiments (the "Standard Test"), seven-week adult male German cockroaches were transferred into oiled, clean Lucite rings (5 cm high x 1 0 cm in diameter) with an aluminum screen (6x7 mesh / cm) attached to the bottom of the ring. The cockroach test vessels (each containing ten cockroaches) were placed in a Water Spray Tower and exposed to a targeted target discharge from above at a distance of 46 cm over 0.5 seconds. The Standard Test uses 1.5 g of the insecticide. As noted below, other amounts were also treated. Immediately after each exposure / discharge, the cockroaches were transferred to a clean greased glass battery jar for the selected observation periods. For purposes of this patent, it is considered that a knockdown is achieved once the cockroach is turned on its back (despite the movement of legs or antennae). This is because once such cockroaches turn on their back in these tests, they usually do not recover. % kill vs. time in seconds (s) Similar tests were conducted on other preferred formulations. It should be appreciated that the above description simply refers to several preferred forms of the invention. Other forms are also possible. For example, we have used other hydrocarbons, such as, d-limonene in our microemulsions.

INDUSTRIAL APPLICABILITY The present invention provides environmentally friendly insecticides. These should be particularly useful in cooking environments or as an atomizer for home plants.

Claims (9)

REIVI NDICATIONS

1 . A method for causing the felling of a crawling insect, comprising: applying an effective amount of a microemulsion to an outer surface of a creeping insect and thereby causing it to turn on its back; wherein the microemulsion comprises: hydrocarbon solvent, which is above 20% by weight, and below 60% by weight, of the microemulsion; surfactant, which is between 1% by weight and 20% by weight of the microemulsion; and at least 10% by weight of water; wherein the microemulsion contains essentially no compound selected from the group consisting of synthetic pyrethroids active as insecticides, natural pyrethrum, organophosphates active as insecticides, carbamates active as insecticides, chlorinated hydrocarbons active as insecticides, and heterocyclics active as insecticides.

2. The method of claim 1, wherein there is less than 6% by weight of surfactant.

3. The method of claim 1, wherein at least 10% by weight of the microemulsion is a hydrocarbon impeller and there is less than 35% by weight of the microemulsion, which is a hydrocarbon solvent apart from the impeller.

4. The method of claim 3, wherein the impeller is selected from the group consisting of dimethyl ether, difluoroethane, propane, butane and mixtures thereof. The method of claim 1, wherein the surfactant comprises an anionic surfactant and a nonionic surfactant. 6. The method of claim 1, wherein said microemulsion further comprises a co-solvent, which is an organic alcohol. The method of claim 6, wherein the organic alcohol comprises: a primary alcohol having between 3 and 12 carbons; and an ether alcohol having less than 20 carbons. The method of claim 7, wherein the primary alcohol is 1-octanol and the ether alcohol is diethylene glycol monohexyl ether. The method of claim 1, wherein the insect is selected from the group consisting of cockroaches, ants, earwigs, and lepisma.