MXPA01008533A

MXPA01008533A - Inhibiting growth of microorganisms in water-based pesticide suspensions

Info

Publication number: MXPA01008533A
Application number: MXPA/A/2001/008533A
Authority: MX
Inventors: Karen L Eagles; Donald W Edson
Original assignee: Bayer Corporation
Priority date: 1999-03-08
Filing date: 2001-08-23
Publication date: 2002-05-09

Abstract

The present invention provides a composition for inhibiting the growth of microorganisms in water-based pesticide suspensions. In accordance with this invention, the composition comprises from about 0.01%to about 60%by weight of a pesticide;from about 0%to about 20%by weight of a surfactant;from about 0%to about 20%by weight of an antifreeze agent;from about 0%to about 5%by weight of a viscosity builder;from about 0.5%to about 2%by weight of acetic acid;and from about 10%to about 99.49%by weight of water. In a preferred embodiment of the invention, the acetic acid has a pH of from about 3 to about 5.

Description

INHIBITION OF THE GROWTH OF MICROORGANISMS IN SUSPENSIONS OF PESTICIDES BASED ON WATER TECHNICAL FIELD OF THE INVENTION The present invention relates to a composition for inhibiting or eliminating the growth of microorganisms in water-based pesticidal suspensions. More specifically, the composition of the present invention consists of a pesticide, a surfactant, an antifreeze agent, a viscosity improver, acetic acid and water. The acetic acid is present in an amount of about 0.5% to about 2% by weight of the total pesticide suspension. The pH of the acetic acid is from about 3 to about 5. BACKGROUND OF THE INVENTION A pesticidal suspension is a homogeneous mixture of small solid particles of pesticide suspended in a liquid medium. The growth of microorganisms in the pesticidal suspension can cause the formation of a solid precipitate and, therefore, a loss of homogeneity in the mixture. The formation of the precipitate and the loss of homogeneity can lead to a failure of the product due to non-uniform applications of the pesticide and to sealing of de-purifiers and nozzles used with the application equipment. A practice developed in the art is the combination or formulation of pesticidal compounds with a preservative to reduce or eliminate the growth of microorganisms in pesticide suspensions. In U.S. Pat. No. 5,283,231 describes formaldehyde, sodium benzoate, glutaraldehyde, and pentachlorophenol as effective preservatives to prevent microbial spoilage in suspensions of low-melting dinitroaniline pesticides. Not all preservatives are effective against all types of microorganisms in all pesticide suspensions. Therefore, there is a need in the art to determine specific preservatives that are effective in a particular fluid aqueous pesticidal composition (i) to reduce or eliminate the growth of microorganisms, (ii) being at the same time easy to handle during its preparation and use and (iii) maintaining an excellent shelf life even during prolonged storage. OBJECTS OF THE INVENTION It is an object of the present invention to provide a composition for inhibiting or eliminating the growth of microorganisms in suspensions of water-based pesticides. This and other objects that will be apparent to those skilled in the art are achieved by the addition of acetic acid to the water-based pesticidal formulation. The composition of the water-based pesticidal formulation includes from about 0.01% to about 60% by weight of a pesticide, from about 0% to about 20% by weight of a surfactant, of about 0% by weight. about 20% by weight of an antifreeze agent, from about 0% to about 5% of a viscosity improver and from about 10% to about 99.49% of water. Acetic acid is added to the pesticide formulation based on water in an amount of about 0.5% to about 2% by weight of the formulation. The pH of the acetic acid is from about 3 to about 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The composition of the pesticidal suspension of the present invention consists of a combination of a pesticidal formulation based on water and acetic acid. The pesticidal formulation includes a pesticide, a surfactant, a thickener, an antifreeze agent and water. The pesticide is selected from the group consisting of an insecticide, a fungicide and a herbicide. Preferably, the insecticide is imidaclo-prid, the fungicide is tebuconazole and the herbicide is metribuzin. The pesticide is present in an amount such that it re-presents from about 0.01% to about 60% by weight of the total pesticidal suspension. Surfactants are used to reduce the surface tension at the water-solid interface and, therefore, they increase the tendency of the water to contact the entire surface of the particles of the active component. Suitable surfactants include wetting agents and dispersing agents. In addition, both anionic and nonionic surfactants are useful. Examples of anionic surfactants include arylalkyl sulphonates and alkyl naphthalenesulfonates. Nonionic surfactants include arylalkyl polyether alcohols, polyalkylene oxide block copolymers, polyalkylene oxide block copolymer monohydric alcohols and alkylphenols of polyalkylene oxide block copolymers. Preferred surfactants include condensates of naphthalene and formaldehyde, sulfonates of naphthalene, alkyl naphthalene sulfonates, lignosulfonates, block copolymers of ethylene oxide and propylene oxide, ethoxylates of alkylalcohols, ethoxylates of al-quilphenols, sodium dodecylbenzenesulfonates, ethoxylates of tristyrylphenol, block copolymers of alkylethylene oxide and propylene oxide, polyacrylates and phosphate esters. The amount of surfactant in the pesticidal formulation is such that it represents from about 0% to about 20% by weight of the total pesticide suspension. A viscosity improver is generally an anionic water-soluble or water-dispersible colloid possessing shear thinning properties, low temperature sensitivity, good stability in both acidic and basic media and compatibility with most inorganic materials. Suitable thickening agents include thickeners. Examples of viscosity improvers include polysaccharide gums, such as xanthan gum, guar gum, gum arabic, organically modified montmorillonite clays, attapulgite clays, carboxy-vinyl copolymers and cellulose ethers. Preferred viscosity improvers include xanthan gum, aluminum magnesium silicates, thickeners of plant extracts and thickeners of cellulose derivatives. The viscosity improver is present in an amount such that it represents from about 0% to about 5% by weight of the total pesticidal suspension.

An antifreeze agent is a depressant of the freezing point. Examples of antifreeze agents include relatively low molecular weight aliphatic alcohols. Preferred antifreeze agents include glycols, glycerin and urea. The amount of antifreeze agent in the pesticidal formulation is such that it represents from about 0% to about 20% by weight of the total pesticidal suspension. The acetic acid in the composition serves as a preservative, which is used to reduce or eliminate the growth of microorganisms in the mixture. The acetic acid is present in an amount such that it represents from about 0.5% to about 2% by weight of the total pesticidal suspension and, preferably, from about 0.6% to about 1% by weight. Further, in a preferred embodiment, the acetic acid has a pH of from about 3 to about 5. The composition of the pesticidal suspension also includes from about 10% to about 99.49% by weight of water. The composition of the pesticidal suspension of the present invention is generally as follows.

Having thus described our invention, the following examples are given as illustrative thereof and are not intended to be in any way limiting the specification and the claims. All weights and percentages given are parts by weight or percentages by weight, unless otherwise indicated. EXAMPLES Example 1 A study was carried out to demonstrate the effectiveness of adding from about 0.0% to about 1% by weight of acetic acid to inhibit or eliminate the growth of microorganisms in a suspension concentrate based on water (CS ) that contained 2 pounds per gallon of insecticide (ADMIRE 2F). The insecticidal formulation was mixed together and homogenized by m of a high shear mixer. The composition of the insecticidal formulation included approximately 21% by weight of a finely ground solid insecticide, approximately 4% by weight of a surfactant, approximately 10% by weight of an antifreeze agent, approximately 0.18% by weight. weight of a viscosity improver, approximately 64% by weight of water and acetic acid levels in the range of 0.0% to 1.0%, as seen in the following Table 1. Acetic acid had a pH in the range of 3 to 5. The samples were then inoculated with species of bacteria specific for the production site and evaluated for a period of 72 hours at a temperature of about 30 ° C. Table 1 Example 2 A study was conducted to demonstrate the effectiveness of 0.0% to 1% by weight of acetic acid in inhibiting or eliminating the growth of microorganisms in a water-based suspension concentrate (CS) containing 1, 6 pounds per gallon of insecticide (PROVADO 1.6F). The insecticide formulation was mixed together and homogenized by m of a high shear mixer. The composition of the insecticide formulation included about 17% by weight of a finely ground solid insecticide, about 4% by weight of a surfactant, about 10% by weight of an antifreeze agent, about 0.25% by weight of a viscosity improver, about 68% by weight of water and acetic acid levels in a range of 0.0% to 1.0%, as shown in Table 2 given below. The pH of the acetic acid was in the range of 3 to 5. The samples were then inoculated with species of bacteria that were specific to the production site and were evaluated over a period of 72 hours at a temperature of approximately 30 °. C.

Table 2 The results shown in Tables 1 and 2 show that the addition of from about 0.6% by weight to about 1% by weight of acetic acid to the pesticide-based water suspension was effective in eliminating the growth of microorganisms throughout the 72-hour trial period. Although the invention has been described in detail in the foregoing for purposes of illustration, it is to be understood that such detail has only that purpose and that those skilled in the art can make variations therein without deviating from the spirit and scope of the invention, except in what may be limited by the claims.

Claims

1. A composition for inhibiting or eliminating the growth of microorganisms in suspensions of water-based pesticides, consisting of: a. from about 0.01% to about 60% by weight of a pesticide, b. from about 0% to about 20% by weight of a surfactant, c. from about 0% to about 20% by weight of an antifreeze agent, d. from about 0% to about 5% by weight of a viscosity improver, e. from about 0.5% to about 2% by weight of acetic acid and f. from about 10% to about 99.49% by weight of water.

2. The composition of Claim 1, wherein the acetic acid is present in an amount of about 0.6% to about 1.0% by weight of the pesticidal suspension.

3. The composition of Claim 1, wherein the pesticide is selected from the group consisting of an insecticide, a herbicide and a fungicide.

4. The composition of Claim 2, wherein the insecticide is imidacloprid.

5. The composition of Claim 1, wherein the surfactant is selected from the group consisting of naphthalene / formaldehyde condensates, naphthalene sulfonates, alkyl naphthalenesulfonates, lignosulfonates, ethylene oxide / propylene oxide block copolymers, alkylalcohol ethoxylates , alkylphenol ethoxylates, sodium dodecylbenzenesulfonates, tristyrylphenol ethoxylates, alkylethylene oxide / propylene oxide block copolymers, polyacrylates and phosphate esters.

6. The composition of Claim 1, wherein the antifreeze agent is selected from the group consisting of glycerin, glycols and urea.

7. The composition of Claim 1, wherein the viscosity improver is selected from the group consisting of xanthan gum, aluminum magnesium silicates, thickeners of plant extracts and thickeners of cellulose derivatives.

8. The composition of Claim 1, wherein the pH of the acetic acid is from about 3 to about 5.