Abstract:
The invention pertains to new composition and a method for increasing the solubility of various agricultural compounds in water at a low pH. The compounds included in this patent are typically not soluble at pH ranges less than 7 to produce commercially viable liquid concentrates. This method requires the use of tallowamine ethoxylates and phosphate esters to lower the pH of various compounds and also keep them soluble in water.

Description:
BACKGROUND OF THE INVENTION 
     Many agricultural formulations contain water soluble salts. These salts, often alkylamine salts, are generally not as active as their acid equivalents. For example, 2,4-Dichlorophenoxyacetic acid (2,4-D acid) is known to be more herbicidally active than the dimethylamine salt of 2, 4-D. However, the 2, 4-D acid is not soluble in water. Solvents used to formulate, 2,4-D acid are known to be phytotoxic to plants and enhance herbicide volatility and subsequent drift to non-target areas. In another example, boron is known to be available to plants only in the boric acid form. However, boric acid is only soluble at relatively low concentrations in water, while the monoethanolamine salt of boric acid is known to be much more soluble. 
     U.S. Pat. No. 4,332,609 issued to Ott, which is incorporated by reference in its entirety, discusses the means of producing just such a water soluble concentrate of boric acid and monothanolamine. The disadvantage is that the plants must convert this boric acid monoethanolamine complex to boric acid in order to use it. Furthermore, boron is often applied in conjunction with a variety of agricultural pesticides which are subject to degradation at high pH ranges. The boric acid monothanolamine salt produces high pH solutions and therefore is detrimental to many pesticides. 
     Fattyamine ethoxylates have been known to be used in agricultural formulations in the past. Specifically, tallowamine ethoxylate surfactant is known to enhance glyphosate activity and translocation. 
     Phosphate esters of alkylphenolethoxylate and alcohol ethoxylates have been used in agriculture traditionally as buffering agents and compatibility agents. U.S. Pat. No. 4,770,694 assigned to Kao Corp., which is incorporated by reference in its entirety, describes the use of phosphate esters to suspend a water insoluble biocide. However, Kao does not discuss the pH as a relevant factor in solubility, and further does not address water soluble compounds. 
     U.S. Pat. No. 4,440,562 assigned to Monsanto Company, which is incorporated by reference in its entirety, describes the use of phosphate esters to couple the isopropylamine salt of glyphosate into the water insoluble 2-haloacetanilide herbicide. Again, pH is not a relevant factor and this patent does not address the use of other pesticides than glyphosate. 
     U.S. Pat. No. 5,389,598 assigned to Monsanto Company, which is incorporated by reference in its entirety, describes a storage stable aqueous composition containing 
     (a) water-soluble pesticide or plant growth modifying agent, 
     (b) an alkylamine surfactant, 
     (c) a C 6  -C 22  saturated or unsaturated alkyl monocarboxylic or dicarboxylic acid 
     (d) and water. 
     The third ingredient (c) C 6  -C 22  saturated or unsaturated alkyl monocarboxylic or dicarboxylic acid is essential and must be present in a ratio alkoxylated alkylamine surfactant to C 6  -C 22  saturated alkyl mono or dicarboxylic acid from at least about 2:1. Our invention works with none, essentially none or even a low ratio less than 2:1 such as 1:1 or less of amine to mono-or dicarboxlic acid. Preferably, there is essentially none or even no C 6  -C 22  saturated alkyl mono or dicarboxylic acid present. Furthermore, this patent requires the use of acetylenic diol surfactants which are not required by this invention. In fact, this invention works without any acetylenic diol surfactants being present or essentially no acetylenic diol surfactants being present. 
     SUMMARY OF THE INVENTION 
     The present invention is a homogenous agricultural liquid composition containing at least an acidic ester surfactant, and an amine containing surfactant, preferably a fatty amine ethoxylate surfactant, at least one other agricultural chemical. The agricultural chemical referred to herein, can used in agricultural or non-applications. The agricultural applications include, but are not limited to pesticide, fertilizer, or plant growth regulators. The non-agricultural applications include, but are not limited to forestry, aquatics, right of way (such as the areas along roads or medians), turf (such as lawns, golf courses etc.) ornamental (such as plants for their beauty) municipal (parks, school, open land, etc). 
     Optionally, other surfactants or formulation aids can be added. The formulation can have a pH of less than about 7. It is also possible to add a buffering agent to further decrease the pH of the composition. Preferably, the acidic ester surfactant is a phosphate ester and the fatty amine is a tallowamine ethoxylate. The composition allows water soluble salts of agricultural chemicals to remain stable and soluble at lower than normal pH ranges. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     It has been surprisingly discovered that a wide range of water soluble compounds can be stabilized at lower than normal pH ranges using a combination of acidic ester surfactants and amine containing surfactants such as but not limited to fatty amine ethoxylates. In addition, the composition can contain a phosphate ester surfactant and a tallowamine ethoxylate surfactant. 
     The acid ester surfactants are of the formula ##STR1## and more preferably of the formula (I) for the diester, ##STR2## or of the formula (II) for the monoester ##STR3## where 
     R 1  is --H or and alkyl or akylaryl group, 
     R 2  is --H, or an alkyl or alkylaryl group, 
     x, z, a, and c are identical or different and are moles of ethylene oxide and are a number from 0 to 100, and preferably from 1 to 100, 
     y and b are identical or different and represent moles of propylene oxide and are a number from 0 to 100, and the sum of x+y+z+a+b+c should be at least 2, and preferably at least 4. 
     M is either hydrogen or a counterion such as an alkali metal, an alkaline earth metal, ammonium, alkanolamine or the like. 
     The preferred acid ester surfactant is a phosphate ester of nonyl-or octylphenol ethoxylates. The acid ester surfactant is more preferably a phosphate ester of linear or branched alcohol ethoxylates. The acid ester surfactant can be present in an amount from about 1 to about 99% of the composition. The acid ester surfactant is preferably present in an amount sufficient to reduce the pH of the product to less than about 7. 
     The fattyamine alkoxylate can be of the formula ##STR4## 
     where n&#39; and n&#34; are identical or different and are a number from 2 to 4 and y&#39; and z&#39; are identical or different and are a number from 0 to 100 with the sum of y&#39; and z&#39; is from 2 to about 110 and most preferably from 2 to about 50. 
     The fattyamine alkoxylate is preferably of the formula ##STR5## 
     where R 3  is a C 8  -C 25  alkyl, preferably a fatty alkyl group, x and a are moles of ethylene oxide, and y and b are moles of propylene oxide, 
     x and a are identical or different and are a number from 1 to 100 and 
     y and b are identical or different and are a number from 0 to 100 and preferably from 21 to 100 and most preferably from 2 to about 50. 
     Additionally, the fatty amine alkoxylate can be a block copolymer derived from the sequential addition of ethylene oxide and propylene oxide to ethylenediamine of the formula ##STR6## 
     where x, b, r, d are moles of ethylene oxide being identical or different and being da number from 0 to 100, and preferably from 1 to 100, 
     y, a, s, c are moles of propylene oxide being identical or different and being a number from 0 to 100. Preferably the sum of x+b+r+d+y+a+s+c is at least 2, and more preferably the sum is at least 4. 
     The most preferred fatty amine alkoxylate surfactant is a tallowamine ethoxylate. The fatty amine containing surfactant can be present in an amount from about 1 to about 99%. Preferably, the fatty amine containing surfactant is present in an amount sufficient to enhance the efficacy of the crop protection chemicals. 
     The agricultural chemical can be a fertilizer containing boron, zinc, copper, iron, blends of nitrogen phosphorous and potash or mixtures thereof. The agricultural chemical can be a crop protecting chemical such as but not limited to a herbicide. The herbicide can be, but not limited to, dimethylamine (DMA) salt of 2,4-dichlorophenoxyacetic acid, DMA salt of dicamba, sodium salt of dicamba, isopropylamine (IPA) salt of glyphosate, IPA salt of 2,4-dichlorophenoxyacetic acid, sodium salt of acifluorfen, sodium-salt of bentazon, sodium salt of imazethapyr, ammonium salt of imazaquin, IPA salt of imazapyr, sodium salt of asulam or mixtures thereof. The agricultural chemical can be present in an amount from about 1 to about 99%. 
     The composition can contain micronutrients such as boron. In example I, Ott&#39;s patented composition of a monoethanolamine salt of boric acid is further unexpectedly improved by using a blend of phosphate ester and an amine surfactant such as tallowamine ethoxylate. 
     The agricultural formulation can also contain additional surfactants. The preferred additional surfactants include, but are not limited to: 
     a) sorbitan fatty acid ester, 
     b) polyethoxylated derivative of a sorbitan fatty acid ester, 
     c) fatty alkanolamides of the formula ##STR7## wherein R is an alkyl group having about 6 to about 25 carbon atoms; R&#39; and R&#34; independently of one another are selected from the group consisting of hydrogen, ##STR8## d) peg esters of the formula ##STR9## wherein R is a fatty alkyl having from about 2 to about 25 carbon atoms, R&#39; is a fatty alkyl having from about 2 to about 25 carbon atoms or H and m is a number from 1 to about 100, 
     e) silicone surfactants of the formula ##STR10## wherein R and R&#39; independently from one another are hydrogen, alkyl having from 1 to about 20 carbon atoms, preferably 1 to 4 carbon atoms or an alkyl ester group having 1 to 20 carbon atoms, preferably 1 to 4 carbon atoms, x is a number from about 1 to about 100, preferably from about 1 to about 5, a is a number from about 3 to about 25, b is a number from about 0 to about 25, n is a number from about 2 to about 4 and 
     f) ethoxylated fatty acids ##STR11## wherein R is an alkyl group having from about 6 to about 25 carbon atoms, n is a number from 1 to about 100, 
     g) alkyl ethoxylates 
     
         RO(CH.sub.2 CH.sub.2 O).sub.x H 
    
     wherein R is an alkyl group having from about 1 to about 50 carbon atoms and x is a number from 1 to about 100, 
     h) alkylphenol ethoxylates ##STR12## wherein R is H or an alkyl having from about 1 to about 20 carbons, R&#39; is H or an alkyl having from about 1 to about 20 carbons and n is a number from 1 to about 100, 
     i) polypropylene glycols ##STR13## wherein n is a number from 1 to about 100, j) tristyrylphenol alkoxylates, 
     k) amine ethoxylates ##STR14## wherein x and y independently of one another are a number from about 1 to about 100 and R is an alkyl having from 1 to about 25 carbon atoms, 
     l) N-Acyl Sarcosines and Sodium N-Acyl Sarcosinates, 
     m) alkylaryl polyethoxy phosphate ester, 
     n) alkylaryl polyethoxy carboxylate ester, 
     o) tristyrylphenol alkoxylate phosphate esters, 
     p) tristyrylphenol alkoxylate carboxylate esters, 
     q) Phosphate esters of block copolymers of ethylene and propylene oxide or 
     r) alkylpolyglucosides. 
     Additionally, buffering agents can be added to the composition to further reduce the pH. The buffering agents include, but are not limited to, 
     a) alkylaryl polyethoxy phosphate ester, 
     b) C 1  -C 6  carboxylic acids, 
     c) C 1  -C 6  dicarboxylic acids, 
     d) phosphoric acid, 
     e) citric acid, 
     f) glutaric acid, 
     g) gluconic acid, 
     h) lactic acid, 
     i) glycolic acid, 
     j) acrylic acid, 
     k) carboxylated alcohol ethoxylate, preferably of the formula 
     
         R--O(CH.sub.2 CH.sub.2 O).sub.x H 
    
     R is a carboxylic acid having from 1 to about 25 carbon atoms and x is from 1 to about 20 moles ethylene oxide, 
     l) ethoxylated alkylaryl phosphate esters; 
     m) ethoxylated alkylphenol carboxylate esters; 
     n) tristyrylphenol alkoxylate phosphate esters; 
     o) tristyrylphenol alkoxylate carboxylate esters; 
     p) fatty acids and blends thereof and 
     q) phosphate esters of block copolymers of ethylene and propylene oxide. 
     The formulation can optionally contain water insoluble agricultural chemicals such as but not limited to pesticides. The pesticides can be, but are not limited to ester of dichlorophenoxyacetic acid, trifluralin, pendimethalin, propanil, atrazine, benefin, chloroimuron, linuron, alachlor, metalochlor or mixtures thereof. 
     Furthermore the agricultural formulation can have a surface tension of less than 60 dynes as measured by the Du Nuoy Surface Tensiometer at a concentration of 1-10%. 
     The formulation is made by mixing all the ingredients together. Other optional ingredients include but are not limited to dyes, thickeners, anti-corrosion agent, anti-caking agents, stabilizers, gel inhibitors, anti-freezes, anti-foam agents, mixtures thereof and the like. 
     The following examples are listed to help illustrate the advantage of the new agricultural formulation. 
    
    
     EXAMPLE 1 
     
         ______________________________________Ingredients          % in formula______________________________________Monoethanolamine salt of boric acid                80.0Tallowamine ethoxylate surfactant                10.0Phosphate ester surfactant                10.0______________________________________ 
    
     The improvement of this formula is in the resulting pH of the composition. The monoethanolamine salt of boric acid has a pH of 9.0 on its own. The composition of Example 1 has a pH of 6.65. It is generally acknowledged in most agricultural applications that plants can only use boron in it&#39;s acidic form. However, the solubility of boric acid alone is very low at pH ranges less than 8.0. Therefore, as evidenced in the patent issued to Ott containing monoethanolamine salt composition, most agricultural boron formulations use high pH solutions to increase boron solubility, and rely on environmental conversion of the boron to lower pH form which can then be used by plants. 
     The patented composition can contain pesticides such as the dimethylamine salt of 2,4-Dichlorophenoxyacetic acid (2,4-D Amine). In Example 2, a dimethylamine salt of 2,4-D is formulated which with phosphate ester surfactants, tallowamine ethoxylate surfactant, and other wetting agents. The resulting composition has a pH of about 4.5, as opposed to conventional dimethylamine salt of 2,4-D formulations which have a pH of about 8.5. Furthermore, the formulation is significantly more compatible with liquid fertilizer solutions. In mixes containing only urea-ammonia nitrate fertilizer, the traditional 2,4-D Amine product formed crystals. The formulation in Example 2 produced a nice clear solution. 
     EXAMPLE 2 
     
         ______________________________________Ingredients         % in formula______________________________________Dimethylamine salt of 2,4-D               69.80Tallowamine ethoxylate surfactant               6.00Phosphate ester surfactant               14.00Citric acid         0.70Alcohol ethoxylate surfactant               2.00Water               7.50______________________________________ 
    
     The stability of the composition in Example 2 is excellent, over more than 2 months in accelerated storage tests, and therefore is expected to be stable at normal temperatures for at least 2 years. Furthermore, efficacy trials showed enhanced herbicide activity with the formulation of Example 2 when compared with commercial 2,4-D Amine products. 
     In Example 3 the compatibility of two water soluble herbicides is enhanced using phosphate ester surfactants and tallowamine ethoxylate surfacts. Plateau herbicide is a water-based formulation, containing the active ingredient, imazameth, and manufactured by American Cyanamid. Garlan 3A herbicide is a water based formulation containing the triethylamine salt of triclopyr, and manufactured by Dow Elanco. These two products cannot be mixed at normal use rates without dilution by water. A typical tank mix of these two herbicides would contain 4 ounces of Plateau and 32 ounces of Garlon 3A. A direct mixture of these herbicides salt out quickly. The addition of nearly 50 ounces of water is required to keep these herbicides solubilized for extended periods of time. The addition of as little as 21 ounces of an adjuvant containing tallowamine ethoxylates and phosphate ester surfactants maintains the solubility of the herbicide mixture. 
     In Example 4, a dimethylamine salt of 2,4-D is formulate with phosphate ester block copolymer surfactants, a block copolymer derived from the sequential addition of ethylene oxide and propylene oxide to ethylenediamine, and other wetting agents. The resulting composition has a pH of about 5.0, as opposed to conventional dimethylamine salt of 2,4-D formulations which have a pH of about 8.5. 
     EXAMPLE 4 
     
         ______________________________________Ingredients             % in formula______________________________________Dimethylamine salt of 2,4-D                   69.80EO/PO Block Copolymer of Ethylenediamine                   5.00Phosphate ester EO/PO Block Copolymer                   5.00Alcohol ethoxylate surfactant                   5.00Water                   15.20______________________________________ 
    
     The inventive composition can be used in a method of controlling vegetation by adding the inventive composition to foliage of plants. Further, the inventive composition can be used in a method of promoting plant growth and/or eliminating the damage caused by insects by adding the inventive composition to foliage of plants. 
     While there is shown and described certain specific structures embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described.