CA1120745A - Flowable 2-chloro-n-isopropylacetanilide - Google Patents
Flowable 2-chloro-n-isopropylacetanilideInfo
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- CA1120745A CA1120745A CA000347785A CA347785A CA1120745A CA 1120745 A CA1120745 A CA 1120745A CA 000347785 A CA000347785 A CA 000347785A CA 347785 A CA347785 A CA 347785A CA 1120745 A CA1120745 A CA 1120745A
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Abstract
ABSTRACT OF THE DISCLOSURE
A flowable aqueous suspension concentrate of 2-chloro-N-isopropylacetanilide having desirable storage and dispersion properties contains, by weight, from 30 to 60 percent of finely divided particulate 2-chloro-N--isopropylacetanilide; from 1 to 10 percent of (a) an anionic surfactant or (b) a nonionic surfactant or (c) a mixture of an anionic surfactant with a nonionic surfac-tant; up to 1.0 percent of a heteropolysaccharide gum;
from 1 to 10 percent of an anticaking agent selected from a suitable absorbent clay, diatomaceous earth, or a finely divided precipitated hydrated silica or a mix-ture of any such clay or diatomaceous earth with such hydrated silica; from 0.1 to 6 percent of a dispersing agent; up to 1 percent of an antifoaming agent and the balance substantially water. The flowable concentrate vehicle is additionally applicable to herbicide mixtures containing 2-chloro-N-isopropylacetanilide at a concen-tration of at least 30 percent by weight and additionally one or more active herbicide ingredients for use in con-trolling broadleaf weeds.
A flowable aqueous suspension concentrate of 2-chloro-N-isopropylacetanilide having desirable storage and dispersion properties contains, by weight, from 30 to 60 percent of finely divided particulate 2-chloro-N--isopropylacetanilide; from 1 to 10 percent of (a) an anionic surfactant or (b) a nonionic surfactant or (c) a mixture of an anionic surfactant with a nonionic surfac-tant; up to 1.0 percent of a heteropolysaccharide gum;
from 1 to 10 percent of an anticaking agent selected from a suitable absorbent clay, diatomaceous earth, or a finely divided precipitated hydrated silica or a mix-ture of any such clay or diatomaceous earth with such hydrated silica; from 0.1 to 6 percent of a dispersing agent; up to 1 percent of an antifoaming agent and the balance substantially water. The flowable concentrate vehicle is additionally applicable to herbicide mixtures containing 2-chloro-N-isopropylacetanilide at a concen-tration of at least 30 percent by weight and additionally one or more active herbicide ingredients for use in con-trolling broadleaf weeds.
Description
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This invention relates to a flowable aqueous ~-suspension concentrate of the herbicide 2-chloro-N--isopropylacetanilide (propachlor) or a herbicidal mixture of 2-chloro-N-isopropylacetanilide and a triazine herbicide such as 2-chloro-4-(ethylamino)-6-(isopropyl-amino)-s-triazine, having not only desirable storage properties but also being readily dispersible as a tank mix in the field. The invention further relates to a flowable aqueous suspension concentrate of the herbicide
This invention relates to a flowable aqueous ~-suspension concentrate of the herbicide 2-chloro-N--isopropylacetanilide (propachlor) or a herbicidal mixture of 2-chloro-N-isopropylacetanilide and a triazine herbicide such as 2-chloro-4-(ethylamino)-6-(isopropyl-amino)-s-triazine, having not only desirable storage properties but also being readily dispersible as a tank mix in the field. The invention further relates to a flowable aqueous suspension concentrate of the herbicide
2-chloro-N-isopropylacetanilide containing at least 30 percent by weight of 2-chloro-N-isopropylacetanilide and at least one or more active herbicide ingredient useful in controlling broadleaf weeds, particularly those which are sparingly soluble in water or the aqueous suspension vehicle and even more particularly wherein problems are encountered with the propachlor in the mixture.
The preparation of suitable aqueous suspension concentrates of sparingly soluble pesticides has been an important objective of formulators. While wettable 20 powders have been in use for some time, such compositions ;
are frequently undesirable, particularly in the case ~'' ~ 18,246A-F
-- ~; , where the active ingredient is difficult to handle because of such properties as skin sensitivity. Thls is particularly true in the case of the herbicide propachlor.
A description of desired properties of sus-pension concentrates and means for obtaining such proper-ties are described in the chapter by H. Schaller and H. Niessen, entitled "Properties of Suspension Concentrates", in the text, Pesticide Chemistry, Volume V, Gordon and Breach Science Publishers, New York, NY, 1972, p. 441.
French Patent No. 2,247,976 describes aqueous suspensions of pesticides made up of a salt solution as a suspension medium. The French patent describes the preparation of aqueous suspensions of pesticides having a melting point above 50C and a solubility in the suspension medium of less than 500 parts per million (ppm) at 25C and employs in such compo-sitions a major proportion of a soluble salt such as sodium sulfate, ammonium sulfate or sodium biphosphate;
sodium lignosulfate; an anionic surfactant such as sodium alkyl benzene sulfonate, sodium alkyl naphtha-lene sulfonate, or sodium dioctylsulfosuccinate; and, in some mixtures, a combination of kaolinite clay and synthetic silica; the pesticide employed; and the balance water. Such compositions are taught to contain from about 8 to about 40 percent by weight of the pesticide, from 40 to about 91.9 percent by weight of the soluble inorganic salt, from 0.1 to 10 percent by weight of lignosulfate salt, up to 3 percent of a wetting agent, a corrosion inhibitor, if desired, in minor amount and the balance substantially water.
Such compositions contain no xanthan gum and no non-ionic surfactant.
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~3 Of particular interest is U.S. Patent 3,948,636 and its British counterpart 1,421,092 as w~ll as its South African counterpart identified as Patent Appli-cation No. 74/2789. These patents describe and claim flowable aqueous suspension concentrates of relatively insoluble pesticides such as propachlor, i.e., 2-chloro--N-isopropylacetanilide, containing from 10 to 60 per-cent by weight of the pesticide, from 1 to 10 percent of a nonionic surfactant, from 0.02 to 1 percent o~ a heteropolysaccharide gum, up to 10 percent of an anticaking agent, up to 5 percent of an antifoaming agent and up to 10 percent of a freeæing point depres-sant, and the balance water.
Such a concentrate composition suffers from the disadvantage that crystal growth, sometimes called Ostwald-ripening, appears to take place, and in any event the suspension settles out on accelerated storage (at about 50C) of more than 7 weeks and resùspension thereafter becomes increasingly difficult. Moreover, the patented composition suffers from the further disadvantage that it does not disperse as well as would be desired on preparation of a tank mix. This is particularly noted if the water employed in making up the tank mix is hard water such as might be drawn from a well in the field. The xanthan gum of the composition is of little utility when dilution is made to the tank mix and no dispersant is provided in the patented formulation.
Propachlor is particularly difficult to work with since it has a solubility in water at 25C of approximately 580 ppm by weight while at 40C the solubility rises to about 1000 ppm by weight. At this level of solubility, crystal growth can occur leading 18,246A-F ~3-: ~ . . - . . -:. - ~ . . . ; -~ ~; - . , to particle size enlargement and sedimentation or gelation of suspended particles in a pesticide formu-lation under normal storage conditions which can range from ambient winter temperatures to about 50C. If the settled particles are not readily resuspended and/or are not readily dispersible on dilution with water, the formulation is commercially unacceptable to most users.
The problem is made more difficult by the fact propachlor tends to crystallize as thin enlongated crystals.
The triazine herbicides of commercial interest are sparingly soluble in water, less soluble than pro-pachlor, and are not difficult to formulate. The problems with propachlor must still be met in a pro-pachlor-triazine mixture to be suspended in a flowable suspension concentrate. Likewise, the problems with propachlor must still be met in making a suitable flowable suspension concentrate of a mixture of pro-pachlor and one or more other active herbicides useful for the control of broadleaf weeds wherein at leasi 30 percent by weight propachlor is contained in the concentrate.
In accordance with this invention a flowable a~ueous suspension concentrate of propachlor or a propachlor-triazine mixture or a mixture of propachlor and at least one additional active herbicide useful for the control of broadleaf weeds wherein the concentrate contains at least 30 percent by weight propachlor having improved storage properties and further improved dis-persibility on preparation of tank mixes in the field consists essentially of, by weight:
from 30 to 60 percent of particulate propachlor or propachlor-triazine mixture or mixture of propachlor 1~,246A-F -~-., .
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and at least one other said herbicide having a particle size mainly in the range of 1 to 10 microns;
from 1 to 10 percent of an anionic surfactant or a nonionic surfactant, or a mixture of an anionic S surfactant and a nonionic surfactant;
up to 1.0 percent of a heteropolysaccharide gum;
from 1 to 10 percent of an anticaking agent selected from ball clays of the kaolinite group such as Bandy Tan, Gleason, ~tratton, or Barden clay; diatomites such as Celite~ 209 diatomaceous earth, Celatom~ MM-309 diatomaceous earth; a finely divided precipitated hydrated silica; and a mixture of any such ciays or diatomite with such hydrated silica;
- 15 from 0.1 to 6 percent of a dispersing agent, with the proviso that when the surfactant is a nonionic surfactant or a mixture containing more than 4 parts nonionic surfactant per part of anionic surfactant the proportion O$ dispersing agent is at least 1.0 percent;
up to 1.0 percent of an antifoaming agent;
and the baIance substantially water;
the composition essentially having a viscosity at 25C of 200 to 3500 centipoises and preferably 700 to 2000 centipoises as determined by a Brookfield Viscometer Model RVT (No. 3 spindle - 10 rpm).
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Generally it is desirable to include in the composition from 2 to 15 percent of a freezing point depressant. Also it is essential when the composition is not to be used immediately to add an effective amount of a preservative to prevent or inhibit microbial growth, generally 0.1 to 0.25 percent by weight being sufficient, based on the total formulation.
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The composition of the invention is a flow-able aqueous suspension concentxate of propachlor, or propachlor-triazine herbicide mixture or mixture of propachlor with at least one additional herbicide S useful in controlling broadleaf weeds wherein the concentrate contains at least 30 percent by weight propachlor exhibiting substantially improved storage stability and water dispersibil:ity over the compo-sitions described in U.S. Patent 3,948,636. Like the compositions there described, the present compo-sition is capable of incorporat:ing high solids in concentration, e.g., up to and including 6 pounds of propachlor or total herbicide solids per gallon.
On careful selection of ingredients here set forth, up to the theoretical maximum concentration somewhat above 6 pounds of propachlor or herbicide mixture per gallon may be properly suspended.
In general, the propachlor content of the flowable compositions of this invention may vary from 30 to 60 percent by weight. In those compositions, containing high solids content of commercial interest, the propachlor content typically varies from 40 to 60 percent by weight. In practice, the propachlor and any other sparingly soluble herbicide actively present are employed in a finely divided form having an average particle size ranging preferably between 1 to 10 microns. It is desirable that the propachlor and other insolubles have an average particle size within the stated range so that the greatest particle surface per unit of weight will be provided, thereby allowing the solids to be most homogenously suspended.
In preparing the flowable aqueous suspension concen-trate of the invention, it is necessary, in order to 1~,246A-F -6-.
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bring the propachlor and any other solids to the desired average particle size, to subject the particulate material to air milling, or preferably sand milling or ball milling after initial hammer milling or other eonventional comminuting treatment known in the art.
It is to be noted, moreover that it i6 also possible to prepare suitable compositions which incor-porate, in addition to the propachlor, one or more solid, water-soluble pesticide components. Water soluble components have a solubility greater than 2000 ppm. In such composition, the soluble pesticide will of course be in solution in water as the con-tinuous phase. Other suitable active herbicides inelude dieamba, i.e., 2,5-diehloro-6-methoxy benzoie aeid and amine salts thereof as well as sparingly soluble esters; 2,4-dichlorophenoxyacetic acid and ; amine salts thereof as well as the sparingly soluble butoxyethanol ester; bifenox and linuron as well as i the aforementioned herbicidal triazines. Sparingly soluble compounds are those having a solubility below 1500 ppm and preferably below 200 ppm.
The three-way eombination o~ heteropolysae-eharide gum, the surfactant or surfactants and the dispersant employed in combination comprise an important dispersing-suspending system in an important embodiment of the flowable pesticide composition of this inven-tion. It is critical to employ these components in eertain prescribed ratios both in relation to each other and to the concentration of pesticide component~
in order to obtain compositions with the desired storage stability and water dispersibility.
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In another preferred embodiment, the gum is substantially or entirely omitted, while the relative proportion of surfactant is increased in preparing higher propachlor solids compositions containing 5 or more pounds propachlor per gallon. In such embodiment in which the propachlor or propachlor-triazine com-ponent or other solids mixture is relatively high and the gum is largely or entirely omitted, the surfactant and dispersant serve as the dispersing suspending system.
The terms "heteropolysaccharide" and "hetero-polysaccharide gum" as used-herein are meant to include the use of the polysaccharide in the form of the colloid and its salts, e.g. amine derivatives prepared by the method disclosed for example in U.S. Patent 3,244,595.
The heteropolysaccharde which is commonly designated in the art as the xanthan gum is a high molecular weight linear cellular material prepared by the action o~ bacteria of the genus Xanthomonas on carbohydrates.
It has a molecular weight in excess of 200,000, pre-ferably over one million. A variety of carbohydrates can be fermented with various species of this genus Xanthomonas to produce the heteropolysaccharide.
Examples of suitable bacterium species of the genus Xanthomonas include X. campestris, X. carothee, X. inconue, X. begoniae, X. malvacerum, X. vesicatoria, _ translucens, and X. vaculorum, among others.
Suitable carbohydrates include, glucose, sucrose, fructose, maltose, lactose, galactose, soluble starch, corn starch, potato starch, and the like. Preparation of heteropolysaccharides suitably used herein is described in greater detail but not solely in U.S.
18,246A-F o8_ Patent 3,020,~06. It is to be understood that neither the heteropolysaccharides per se nor their preparation consitute a part of the present invention.
The surfactant system employed in the sus-pending-dispersing system of the flowable composition of this invention is either a b:Lend of anionic and nonionic surfactants or composed entirely of either a nonionic surfactant or an anionic surfactant. A
blend consisting of up to 4 parts nonionic per part anionic surfactant is treated or used in the same manner as anionic surfactant, while a blend consis-ting of more than 4 parts nonionic per part o~
anionic surfactant is treated or used in the same manner as nonionic surfactant used as sole dispersant.
Specific suitable anionic surfactants are selected from the following classes or types of materials:
ethoxylated monohydric sulfated alcohol salts of sodium, potassium, alkaline earth metals, ammonium, alkyl amines, alkanolamines or blends thereof (also 20 designated in the art as alkyl polyether alcohol ;
sulfates); ethoxylated sulfated alkylphenol salts of sodium, potassium, alkaline earth me-tals, ammonium, alkyl amines, or alkanolamines or blends thereof (also designated in the art as alkylaryl polyether alcohol sulfates); and the sodium, potassium, alkaline earth metal, or ammonium salts of alkyl phenoxybenzene disulfonates.
Specific suitable nonionic surfactants are selected from the following classes or types of non-ionic surfactant materials: ethoxylated alkyl phenols(also designated in the art as alkylaryl polyether alcohols); ethoxylated aliphatic alcohols (or alkyl ~polyether alcohols); ethoxylated fatty acids (or .
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polyoxyethylene fatty acid esters); ethoxylated anhydrosorbitol esters (or polyethylene sorbitan fatty acid esters); ethoxylated polyoxypropylene glycols (polyalkylene oxide block copolymers);
ethoxylated polyoxypropylene monohydric alcohols (polyalkylene oxide block copolymers of monohydric alcohols); and ethoxylated polyoxypropylene alkyl phenols (polyalkylene oxide block copolymers of alkyl phenols).
. Of these the preferred surfactants are a blend of:
(a) (1) ethoxylated monohydric alcohol, i.e., alkyl polyether alcohol sulfates of the general formula:
+
C10 to C15 linear or branched chain alkyl group, y is an integer of from 2 to 19 and M is a cation selected from ammonium, calcium, magnesium, potassium, sodium and zinc;
(2) ethoxylated, sulfated alkyl phenols, i.e., alkylaryl polyether alcohol sulfates of the . general formula:
R ~ o-(cH2cH2o)y-cE2cH2oso3 M
wherein R is a C8 to C12 linear or branched chain alkyl, y is an integer of 3 to 13 and M is a 25 - cation selected from ammonium,- calcium, magnesium, potassium, sodium and zinc; alone or in admixture with one or more of the following nonionic surfactants:
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(b) (1) ethoxylated polyoxypropylene glycols, i.e., polyalkylene oxide block copolymers of the general formu]a:
HOCH2 C~I2 O- ( CH2 CH20 ) X- ( C3H6 ) y wherein x is an integer of from 5 to 95 and y is an integer from 5 to 150 and the average molecular weight of the copolymer is in the range of 1800 to 9000;
(2) ethoxylated polyoxypropylene monohydric alcohols, i.e., polyalkylene oxide block copolymer of mononydric alcohols of the general formula:
R-ocH2cH2o-(cH2cH2o)x (c3H6o)y wherein R is a Cl to C8 linear or branched - chain alkyl group, x is an integer of from 5 to-70 y is an integer of from 5 to 55 and the average molecular weight of the copolymer is in the range of 2400 to 3500; and (3~ ethoxylated polyoxypropylene alkyl phenol, i.e., polyalkylene oxide block copolymer of alkyl phenol of the general formula:
- R ~ (CH2CH2O)X-(C3H6O)y wherein R is a C8 to C12 linear or branched chain alkyl group, x is an integer of 30 to 60, y is an integer of 5 to 35, and the average molecular weight of the copolymer is about 3000.
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Utilizing these surfactant systems, formula-tions are obtained with optimum water dispersibility and adequate storage stability. Within this class, `
especially preferred combinations of surfactants are 18,246A-F -11-.. , ~, , :. i - .I , ~ ~ . --.
... . . ~.: .. ~ - , ~12-any of (a) alkyl polyether alcohol sulfate wherein R is a C12 alkyl, y is an integer selected from 3 and 4 and M is sodium or ammonium; or alkylaryl polyether alcohol sul-fate wherein R is a C9 alkyl, y averages 3 and M is sodium or ammonium; with one or more of (b) polyalkylene oxide block copolymer wherein the weight percent of the polyoxyethylene units in the mo:Lecule range from 30 to 60 percent of the average molecular weight of the polymer;
polyalkylene oxide block copolymer of monohydric alcohol wherein R is a C4 alkyl; and polyalkylene oxide block copolymer of alkyl phenol wherein R is a Cg alkyl, the surfactants being otherwise as described in the general categories above.
In compositions containing a higher propachlor solids content, such as 40 to 60 percent by weight, the xanthan gum generally is employed in an amount ranging from 0.1 to 0.5 percent by weight; the surfactant in an amount ranging generally from 2 to 7 percent by weight;
and the dispersant in an amount ranging from 0.5 to 4 percent by weight, and most preferably in an amount ranging from 0.5 to 2 percent by weight. If each of these components were employed separately as the sole suspending or wetting agent in otherwise similar for-mulations, the troublesome solid pesticide component, i.e., propachlor, would soon settle out of the continuous water phase. ~epending upon the length of time allowed to stand after the settling of the solid, it would become increasingly difficult to resuspend the solids, even with vigorous and prolonged agitation.
In the pesticide composition of this inven-tion, it is necessary to employ each of the hetero-polysaccharide and surface active agent (or wetting 18,246A-F -12- -. .
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agent) and dispersant components within the ranges stated above in order to obtain the desired compo-sition properties. Formulations containing amounts of these components outside the stated ranges will either be too low or too high in viscosity and non-flowable, exhibiting inferior water dispersibility and unsatisfactory storage stability of the sus-pension concentrate.
In the pesticide composition of this inven-tion containing the heteropolysaccharide gum as well as dispersant and one of (a) an anionic surfactant, (b) a nonionic surfactant, or (c) both an anionic and a nonionic surfactant, it is necessary to employ each within the ranges stated hereinabove in order to assuredly obtain the desired composition properties.
- Formulations containing amounts of these components outside the stated ranges will either be too low in viscosity with a tendency to settle out solids or too high in viscosity and nonflowable, exhibiting inferior water dispersibility on dilution and unsatisfactory storage stability.
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In concentrate compositions containing 5 pounds or more propachlor per gallon of concentrate, the composition tends to be thicker, i.e., more vis-cous, because of the higher solids content. This ispreferably overcome by reducing and/or altogether omitting the amount of heteropolysaccharide gum other-wise employed, while employing the surfactant at a concentration of at least 6 percent by weight, and 18,246A-F i13-, .
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~14--preferably also increasing the dispersant to aneffective amount above 1 percent by weight, gen-erally to 2 percent by weight.
Compositions having viscosities ranying from 300 to 4500 centipoises (cps), and more preferably 700 to 3500 (cps), as measured with a Brookfield Viscometer, Model RVT (No. 3 Spindle - 10 rpm) gen-erally will exhibit the desired flowability char-acteristics. As preYiously mentioned, the hetero-polysaccharide gum and the described surfactantsand the dispersant, in combination, comprise one of the dispersing-suspending systems of the flowable propachlor compositions of this invention. In compositions containing higher propachlor content, such as, at least 50 percent by weight of propachlor, a desirable dispersing-suspending system contains more surfactant, more dispersant and little or no gum. These components must be ratioed properly to each other and to the propachlor concentration in order to obtain compositions with desirable storage stability and water dispersibility.
Thus, the ratio, by weight, of propachlor to the anticaking agent, or flow-aid, should be in the range of from 5.5 to 1 to 26 to 1. Nonionic surfactant may be omitted altogether but preferably is employed in a ratio of, by weight, 1 to 2 with respect to the amount of anionic surfactant in the composition. The dispersant should be used in an effective amount within the range herein recited as needed to obtain ready dispersibility of the solids on dilution in making a tank mix and as an inhibitor of crystal growth.
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Also critical to the storage stability of these compositions is both the type and concentration of the inert carriers used in these formulations functioning as flow-aids or anticaking aids.
Numerous pesticidal dust diluents and car-riers are known to the art. The "Handbook of Insec-ticide Dust Diluents and Carriers" by T. C. Watkins and L. B. Norton, Dorland Books, Caldwell, New Jersey (1955) lists many of those commonly used in the trade for those purposes. We have found that many of those are also commonly used in the art for flowable pes-ticidal compositions that will not serve to maintain, in combination with the present suspending-dispersing system, the desired storage stability of the composition . 15 under extreme storage conditions. The suitable inert carriers are selected from the ball (China) clays such as Bandy Tan, Gleason, Stratton and Barden clays; the diatomites sold as, Celite~ 209 and Celatom~ MN-39;
and a finely divided synthetic precipitated hydrated silicon dioxide (silica) such as the silica sold under the trademarks or tradenames Cab-0-Sil~ and Hi-Sil~, e.g., Hi-Sil~ 233. Any of these are used alone or in combination. For optimum performance character-istics, a blend of a silica and a ball clay of the kaolinite group is preferred. In such a blend, the silica content can range from 5 to 95 percent by - weight of the combination with the preferred com-bination containing 25 to 75 weight percent silica and the balance the ball clay. The total composition, as indicated above, contains from 1 to 10 percent by weight of the anticaking or flow-aid. Preferably the total flowable composition contains from 3 to 8 percent by weight of the anticaking aid.
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The novel and highly essential component of the present suspension concentrate is a dis-persant which facilitates the dispersion or dilution of the suspension concentrate with water in the pre-paration of the final mix in the field, generally referred to as a tank mix. It should be noted that it may be possible to prepare an entirely satisfactory looking and performing suspension concentrate so far as can be ascertained in the concentrate form which is not at all satisfactory upon dilution as the solids tend to settle rapidly, and/or to agglomerate, especially when the tank mix is made up using hard water. It is therefore essential to include in the composition an adequate dispersant.
Even more importantly the dispersant is critical to concentrate stability under various storage conditions such as during freeze-thaw cycles which lead or tend to lead to crystal growth.
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For purposes of the present description and the appended claims a disp~rsant is defined as a polar organic material with dispersant properties which does not lower the surface tension of water more than 30 percent from the normal 72 dynes per square centimeter in contrast to surfactants which lower surface tension of water 50 percent or more-.
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Suitable dispersants are selected from the sodium, potassium, ammonium, calcium, magnesium or zinc salts of the commonly available lignosulfonic acids, the sodium salt being preferred, or, the poly-merized alkyl or alkylaryl sulfonic acid salts, suchas, the potassium, sodiurn, calcium or an~lonium salts, with the sodiurn salt bein~ preferred. A specific 18,246A-F 16-:.
r-j example of a suitable sodium salt of polymerized alkyl, alkylaryl or aralkyl sulfonic acid is:
Daxad~ 27, sodium salt of benzoid alkyl sulfonic acid.
The amount of dispersant used should be in the range of from 0.1 to 6 weight percent, with the preferred amount being in the range of 0.5 to 4 percent and the most preferred amount being 0.5 to 2 percent by weight. Functionally, the dispersant retards or preven-ts settling of the suspended solids and is believed to aid in the prevention or inhibition of crystal growth of the propachlor solids in the aqueous concentrate, as during freeze-thaw cycles.
Should the propachlor or other active herbicide employed in making the suspension concen~
trate of the invention contain acidic manufacturing contaminants causing a 10 weight percent water dis-persion thereof to e~hibit a p~ below 4, then compo-sitions to meet the objectives of this invention must contain somewhat more dispersant than stated above as may readily be determined by trial and error.
Below pH 1 the use of additional dispersant does not compensate adequately for the increased acidity.
Minor quantities of one or more additional compone~ts are preferably included in the composition to provide a highly useful and convenient, practical pesticide composition concentrate. A freezing point depressant is preferably incorporated into the compo-sition to ensure good formulation properties are maintined under adverse storage conditions such as low temperature conditions. A number of freezing point depressants known to the art may be used, 18,246A-F
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however, the best performance is obtained using from 2 to 10 percent by weight of a lower alkylene glycol, such as ethylene glycol or propylene glycol.
In order to facilitate preparation of a tank mix in the field without the formation of undue foam because of the presence of a surfactant and dispersant components hereof, it is highly useful to employ an antifoaming agent. The various commercially available silicone materials or emulsions such as Dow Corning Antifoam A~ are examples of suitable antifoaming agents which may be incorporated in the flowable concentrate in an amount ranging generally from ~.05 to 1 percent by weight of the total compo-sition. A specific example of an antifoaming agent is dimethylpolysiloxane.
It is also generally preferred to employ a preservative to prevent the growth of bacteria and/or fungi in the concentrate during storage. Any of a number of bactericides and fungicides may be employed that are compatible with the present system. A highly satisfactory preservative useable in the present invention is sodium ortho phenyl phenate sold under the trademark Dowicide~ A. Other suitable preservatives are formaldehyde and sodium pentachlorophenate.
Water is employed in sufficient amount ~o serve as the continuous phase for the dispersed pro-pachlor and to achieve reasonahle viscosity charac-teristics compatible with the need for supplying a concentrate with sufficient active solids content.
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In preferred compositions, i.e., those which incor-porate high concentrations of propachlor, from 20 to 40 percent by weight of water will generally be employed.
The order of addition of the ingredients is not especially critical to the preparation of the composition, although it is preferred to mix the heteropolysaccharide gum (if employed), the surfac-tant, the antifoam agent, the freezing point aid, any preservative employed, any soluble herbicide and the dispersant with the continuous water phase before adding the solid propachlor and other sparingly - soluble pesticide and the anticaking aid. The pre-paration is carried out at ambient -temperature with mild agitation, no heat or undue pressure being required to obtain a homogenous suspension. How-ever, in order to ensure that the pesticide ingredient will have the desired average particle size, it is necessary beforehand to subject the propachlor by itself or in combination with any of the above men-tioned ingredients to air milling, hammer milling, ball milling or other conventional comminuting treatment known to the art.
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In combinations of propachlor and most any of the triazine herbicides previously employed as wettable powders, e.g., weight ratios of 2 to 3 parts propachlor per part of triazine have been generally suitable considering the relative dosage rate of each to be applied in the control of undesired vegetation.
The same ratios are desirably employed in preparing a flowable aqueous suspension concentrate of a pro-pachlor-triazine herbicide mixture according to the invention.
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The criteria set forth above for the pre-paration of flowable concentrates containing propachlor only are generally applicable to the preparation of flowable concentrates of the mixtures. The solids - 5 should be comminuted during some stage of preparation of the flowable concentrate to bring the insoluble solid herbicide to a fineness in the range o~ l to 10 microns average particle size in order that the solids are rather readily suspended initially.
The problems of propachlor remain because its solubility is just sufficiently high to create crystal growth possibilities on storage with atten-dant settling out and caking and finally dispersibility problems in the field when tank mixes are prepared.
The triazines of commercial interest are rather sparingly soluble in water. The principal triazines of interest include the s-triazine herbicides atrazine, i.e., 2-chloro-4-(ethylamino)-6-(isopropyl-amino)-s-triazine, having a reported solubility in water at 27C of 33 parts per million by weight (ppmw);
cyanazine, i.e., 2-[[4-chloro-6-(ethylamino)-s-triazin--2-yl]amino]-2-methylpropionitrile, having a reported solubility in water at 23C of 160 ppmw and at 25C
of 171 ppmw; propazine, i.e., 2-chloro-4,6-bis(iso-propylamino)-s-triazine, having a reported solubility in water at 20C of 8.6 ppmw; cyprazine, i.e., 2-chloro--4-(cyclopropylamino)-6-(isopropylamino)-2-triazine, having a reported solubility in water at 25C of 6.9 ppmw and at 40C of about 195 ppmw; and simazine, i.e., 2-chloro-4,6-bis(ethylamino)~s-triazine, having a reported solubility in water at 20C of 5 ppmw and at 85C of 84 ppmw;`and the as-triazine metribuzin, . .
18,246A-F -20-.
,. . . , ~. , ~.. ; . ,, ~ .
..
i.e., 4-amino-6-tert-butyl~3-(methylthio)-as-triazin--5(4H)one ha~ing a water solubility at 20C of 1220 ppmw.
Any of the triazine herbicidal compounds of commercial utility, such as the foregoing, and other sparingly soluble broadleaf herbicides may be combined with propachlor in the weight ratios indicated and in the preparation of an aqueous flowable sus-pension concentrate according to the invention and substantially in the manner described above for flowable concentrates containing propachlor only, achieving the advantages of stability, i.e., rela-tive freedom from serious adverse settling and caking on extended storage, and good dispersibility charac-teristics on preparing tank mixes, even with hard oralkaline waters.
In preparing a flowable concentrate of propachlor and triazine mixture, the total amount - - -of herbicidal solids suspended is in the range of propachlor solids suspended as described hereinabove.
Thus, a 4 pound gallon of the combination of propachlor and a triazine suitably contains, by way of illustration 2.88 pounds of propachlor and 1.12 pounds of triazine, such as atrazine, in one embodiment and 3 pounds of propachlor and 1 pound of triazine in another embodiment.
Similarly, a 5 pound gallon of the combination of propachlor and a triazine such as propazine suitably contains, by way of illustration, 3.6 pounds of pro-pachlor and 1.4 pounds of propazine.
In preparing a flowable concentrate of pro-pachlor and at least one other broadleaf herbicide 18,246A-F 21-.:
' ! ' .
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wherein a triazine is not included unless there is more than one additional broadleaf herbicide, the composition contains at least 30 percent by weight propachlor and is one in which problems of storage stability and final dispersibility as a tank mix are encountered unless prepared according to this invention.
~.
The following examples serve to illustrate the invention and not to limit the claims thereof.
Example l A flowable aqueous suspension concentrate of propachlor is prepared having the following composition:
~eight Ingredients Percent 15 Propachlor-tech. grade (95% active) 43.95 Hi-Sil~ 233 hydrated precipitated silica 1.80 Bandy Tan clay 3.59 p-Nonylphenoxy ethoxylated ethanol sulfate, ammonium salt 2.00 20 Ethoxyiated polyoxypropylene butanol 4.00 Antifoam A~ (dimethylpolysiloxane) 0.25 Kelzan heteropolysaccharide gum (Galaxy XB~ is equivalent) 0.12 Ethylene glycol 5.00 -25 Polyfon H~ lignosulfonate salt 1.00 Water Balance .
18,246A-F -22-.' ' : ' . " ' ' ', '" ' ` , ` ' ~ ' ' "'`~ . ~ '' i '`, ''. ' In general, it is preferred to add the pre-scribed amounts of surfactant and ethylene glycol, such as those set forth above, to the water. This is followed by the lignosulfonate salt and the antifoam ingredient. The heteropolysaccharide gum is normally added as a 2 percent by weight aqueous solution pre-viously prepared or premixed. The foregoing ingre-dients are all added while mixing of the composition continues and with continued agitation, the clay, silica and propachlor are incorporated into the solution. This homogenous composition or suspension is then subjected to one of the conventional com-minuting treatments known in the art, preferably sand milling, to assure that the propachlor solid will have the desired average particle size pre-ferably between 1 and 10 microns average diameter.
The so-prepared composition appears grayish opaque in color. It has a Brookfield viscosity at 23C of 1100 to 1200 cps as determined at 10 rpm. The pH is in the range of 5.5 to 6.5. The specific gravity is 1.15 grams per cc. The concentration of the pesti-cide is 4 pounds active ingredient per gallon.
The formulation is of quite thin consistency and pours easily. When poured into water it exhibits excellent bloom spreading out uniformly into the water and good dispersibility, i.e., no settling of solids.
The medium particle size of the propachlor is 4 to 8 microns with 98~2 percent being less than 20 microns average diameter. Upon dilution of 1 part formulation concentrate per 99 parts water (alkaline 300 ppm water and 100 ppm, 500 ppm and 1000 ppm calcium hard-ness, respectively) there is less than 0.1 milliliter of sediment after one hour in each of the ~ilutions 18,246A-F -23-.
. . , :'- :: ;: - ' .
so prepared. Redispersibility of sediment after 24 hours was good. The formulation shows good physical and chemical stability under accelerated tempera~ure storage at 50C. After more than three months storage at 50C, the formulation shows no significant loss in the active assay, only little liquid separation which readily redisperses to a homogenous suspension on shaking, no gelling, sediment or tendency to agglomerate or become thixotropic. The formulation has passed 10 freeze-thaw cycles (two per week) with no lumps, agglomeration or sediment visible, very little liquid separation which easily redisperses on shaking to a free-flowing homogenous suspension.
Example 2 15 A flowable aqueous suspension concentrate of propachlor was prepared having the ~ollowing composition:
Weight Inaredients Percent -20 Propachlor-tech. grade (about 95% active)57.9 Hi-Sil~ 233 precipitated silica 2.23 Bandy Tan Clay 2.23 p-Nonylphenoxy ethoxylated ethanol sulfate, ammonium salt 2.0 25 Ethoxylated polyoxypropylene butanol 4.0 Antifoam A~ 0.2 Polyfon H~ sodium lignosulfonate 1.5 Ethylene glycol 3.0 Water Balance 18,246A-F -2~-.
~, .
~25-On preparation of the foregoing composition in a manner similar to that described for Example l, the following physical properties were noted:
The so-prepared composition appears grayish opaque in color. It has a Brookfield viscosity at 23C of 3100 cps as determined at 10 rpm. The pH
is in the range of 5.5 to 6.5. The specific gravity is 1.114 grams per cc. The concentration of the pesticide concentration is 5.22 pounds active ingre-dient per gallon.
The formulation pours easily and when pouredinto water exhibits excellent bloom. ~he median par-ticle size of the propachlor is well within the range of 1 to 10 microns. Upon dilution of l part formula-tion concentrate per 99 parts water in several testsusing water of 100 to lQ00 ppm calcium hardness, there is less than 0.1 milliliter of sediment after one hour in each of the dilutions prepared.
The formulation on accelerated temperature ;
20 storage at 50C for more than three months showed no , significant loss in the active assay, only little liquid separation which readily redispersed to a homogenous suspension on shaking, no gelling, sedi-ment or tendency to agglomerate or become thixotropic.
The formulation has passed 10 freeze-thaw cycles (two per week) with no lumps, agglomerate or sediment - visible, very littie liquid separation which easily redispersed on shaking to a free-flowing homogenous -suspension.
18,246~-F -25-.
; "~ ::~.. ': ' '' ~. ' .. . . : , :~ :: :- . .
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Examples 3 and 4 Flowable aqueous suspension concentrates of propachlor were prepared according to the invention from a purified grade propachlor using substantially the procedure of Example 1 wherein comminution is carried out using a ceramic kall mill with ceramic balls for 24 hours. Each concentrate contained by weight 0.12 percent Galaxy XB~ heteropolysaccharide gum with an average molecular weight greater than 200,000; 0.2 percent Polyfon H~ sodium lignosulfonate;
0.45 percent Dow-Corning Antifoam B~, an alkylpoly siloxane; 2 percent of Steol~ 4N sodium lauryl ether sulfate and 2 percent of Terric~ 200 polyalkylene oxide (ethylene oxide-propylene oxide) copolymer of nonylphenyl, 41.8 percent by weight propachlor, 5 per-cent by weight ethylene glycol; in addition to anti-caking agent and the balance water. The antical~ing , agent used in the proportions thereo~ are set forth in Table 1, along with "initial viscosity" values.
"I~itial viscosity" values are determined when the concentrate is freshly prepared. If the initial viscosity does not fall within the range of about 20 to about 3500 as determined at about 25C
with a Brookfield Viscometer, Model RVT (No. 3 spindle - 10 rpm), the composition, especially if somewhat more viscous, may be stable and redispersible but is sufficently hard to handle to be of little or no commerical interest and is therefore outside the scope of this invention.
Test portions of each of the compositions of Examples 3 and 4 remained satisfactory after being subjected to 10 freeze-thaw cycles in one test and 18,246A-F -26-.: . - --, . .
a.3 to at least three months accelerated storage at 50C, showing little or no settling and exhibiting ready dispersability in water to a dilution of 1 to 99 by volume.
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Similar ~ine results like those achieved in Examples 3 and 4 are obtained using Hi-Sil~ 233 alone in place of Bandy Tan clay in the amounts there employed.
Examples 5-8 Flowable aqueous suspension concentrates of propachlor were prepared according to the invention from a purified grade propachlor using substantially the procedure of Example l and wherein the comminution to 1-10 microns was carried out using a ceramic ball mill with ceramic balls and milling for 24 hours to reduce the propachlor particle size to an average value in the range of 1 to lO microns. Each concen-trate contained, by weight, 41.8 percent propachlor,
The preparation of suitable aqueous suspension concentrates of sparingly soluble pesticides has been an important objective of formulators. While wettable 20 powders have been in use for some time, such compositions ;
are frequently undesirable, particularly in the case ~'' ~ 18,246A-F
-- ~; , where the active ingredient is difficult to handle because of such properties as skin sensitivity. Thls is particularly true in the case of the herbicide propachlor.
A description of desired properties of sus-pension concentrates and means for obtaining such proper-ties are described in the chapter by H. Schaller and H. Niessen, entitled "Properties of Suspension Concentrates", in the text, Pesticide Chemistry, Volume V, Gordon and Breach Science Publishers, New York, NY, 1972, p. 441.
French Patent No. 2,247,976 describes aqueous suspensions of pesticides made up of a salt solution as a suspension medium. The French patent describes the preparation of aqueous suspensions of pesticides having a melting point above 50C and a solubility in the suspension medium of less than 500 parts per million (ppm) at 25C and employs in such compo-sitions a major proportion of a soluble salt such as sodium sulfate, ammonium sulfate or sodium biphosphate;
sodium lignosulfate; an anionic surfactant such as sodium alkyl benzene sulfonate, sodium alkyl naphtha-lene sulfonate, or sodium dioctylsulfosuccinate; and, in some mixtures, a combination of kaolinite clay and synthetic silica; the pesticide employed; and the balance water. Such compositions are taught to contain from about 8 to about 40 percent by weight of the pesticide, from 40 to about 91.9 percent by weight of the soluble inorganic salt, from 0.1 to 10 percent by weight of lignosulfate salt, up to 3 percent of a wetting agent, a corrosion inhibitor, if desired, in minor amount and the balance substantially water.
Such compositions contain no xanthan gum and no non-ionic surfactant.
18,246A-F 2-.
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~3 Of particular interest is U.S. Patent 3,948,636 and its British counterpart 1,421,092 as w~ll as its South African counterpart identified as Patent Appli-cation No. 74/2789. These patents describe and claim flowable aqueous suspension concentrates of relatively insoluble pesticides such as propachlor, i.e., 2-chloro--N-isopropylacetanilide, containing from 10 to 60 per-cent by weight of the pesticide, from 1 to 10 percent of a nonionic surfactant, from 0.02 to 1 percent o~ a heteropolysaccharide gum, up to 10 percent of an anticaking agent, up to 5 percent of an antifoaming agent and up to 10 percent of a freeæing point depres-sant, and the balance water.
Such a concentrate composition suffers from the disadvantage that crystal growth, sometimes called Ostwald-ripening, appears to take place, and in any event the suspension settles out on accelerated storage (at about 50C) of more than 7 weeks and resùspension thereafter becomes increasingly difficult. Moreover, the patented composition suffers from the further disadvantage that it does not disperse as well as would be desired on preparation of a tank mix. This is particularly noted if the water employed in making up the tank mix is hard water such as might be drawn from a well in the field. The xanthan gum of the composition is of little utility when dilution is made to the tank mix and no dispersant is provided in the patented formulation.
Propachlor is particularly difficult to work with since it has a solubility in water at 25C of approximately 580 ppm by weight while at 40C the solubility rises to about 1000 ppm by weight. At this level of solubility, crystal growth can occur leading 18,246A-F ~3-: ~ . . - . . -:. - ~ . . . ; -~ ~; - . , to particle size enlargement and sedimentation or gelation of suspended particles in a pesticide formu-lation under normal storage conditions which can range from ambient winter temperatures to about 50C. If the settled particles are not readily resuspended and/or are not readily dispersible on dilution with water, the formulation is commercially unacceptable to most users.
The problem is made more difficult by the fact propachlor tends to crystallize as thin enlongated crystals.
The triazine herbicides of commercial interest are sparingly soluble in water, less soluble than pro-pachlor, and are not difficult to formulate. The problems with propachlor must still be met in a pro-pachlor-triazine mixture to be suspended in a flowable suspension concentrate. Likewise, the problems with propachlor must still be met in making a suitable flowable suspension concentrate of a mixture of pro-pachlor and one or more other active herbicides useful for the control of broadleaf weeds wherein at leasi 30 percent by weight propachlor is contained in the concentrate.
In accordance with this invention a flowable a~ueous suspension concentrate of propachlor or a propachlor-triazine mixture or a mixture of propachlor and at least one additional active herbicide useful for the control of broadleaf weeds wherein the concentrate contains at least 30 percent by weight propachlor having improved storage properties and further improved dis-persibility on preparation of tank mixes in the field consists essentially of, by weight:
from 30 to 60 percent of particulate propachlor or propachlor-triazine mixture or mixture of propachlor 1~,246A-F -~-., .
. .
, ,, '' ~ ' ~ JJ~ ~
and at least one other said herbicide having a particle size mainly in the range of 1 to 10 microns;
from 1 to 10 percent of an anionic surfactant or a nonionic surfactant, or a mixture of an anionic S surfactant and a nonionic surfactant;
up to 1.0 percent of a heteropolysaccharide gum;
from 1 to 10 percent of an anticaking agent selected from ball clays of the kaolinite group such as Bandy Tan, Gleason, ~tratton, or Barden clay; diatomites such as Celite~ 209 diatomaceous earth, Celatom~ MM-309 diatomaceous earth; a finely divided precipitated hydrated silica; and a mixture of any such ciays or diatomite with such hydrated silica;
- 15 from 0.1 to 6 percent of a dispersing agent, with the proviso that when the surfactant is a nonionic surfactant or a mixture containing more than 4 parts nonionic surfactant per part of anionic surfactant the proportion O$ dispersing agent is at least 1.0 percent;
up to 1.0 percent of an antifoaming agent;
and the baIance substantially water;
the composition essentially having a viscosity at 25C of 200 to 3500 centipoises and preferably 700 to 2000 centipoises as determined by a Brookfield Viscometer Model RVT (No. 3 spindle - 10 rpm).
`,:
Generally it is desirable to include in the composition from 2 to 15 percent of a freezing point depressant. Also it is essential when the composition is not to be used immediately to add an effective amount of a preservative to prevent or inhibit microbial growth, generally 0.1 to 0.25 percent by weight being sufficient, based on the total formulation.
18,246A-F -S-, :; ~ " . .
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The composition of the invention is a flow-able aqueous suspension concentxate of propachlor, or propachlor-triazine herbicide mixture or mixture of propachlor with at least one additional herbicide S useful in controlling broadleaf weeds wherein the concentrate contains at least 30 percent by weight propachlor exhibiting substantially improved storage stability and water dispersibil:ity over the compo-sitions described in U.S. Patent 3,948,636. Like the compositions there described, the present compo-sition is capable of incorporat:ing high solids in concentration, e.g., up to and including 6 pounds of propachlor or total herbicide solids per gallon.
On careful selection of ingredients here set forth, up to the theoretical maximum concentration somewhat above 6 pounds of propachlor or herbicide mixture per gallon may be properly suspended.
In general, the propachlor content of the flowable compositions of this invention may vary from 30 to 60 percent by weight. In those compositions, containing high solids content of commercial interest, the propachlor content typically varies from 40 to 60 percent by weight. In practice, the propachlor and any other sparingly soluble herbicide actively present are employed in a finely divided form having an average particle size ranging preferably between 1 to 10 microns. It is desirable that the propachlor and other insolubles have an average particle size within the stated range so that the greatest particle surface per unit of weight will be provided, thereby allowing the solids to be most homogenously suspended.
In preparing the flowable aqueous suspension concen-trate of the invention, it is necessary, in order to 1~,246A-F -6-.
-- .. . .. . .
bring the propachlor and any other solids to the desired average particle size, to subject the particulate material to air milling, or preferably sand milling or ball milling after initial hammer milling or other eonventional comminuting treatment known in the art.
It is to be noted, moreover that it i6 also possible to prepare suitable compositions which incor-porate, in addition to the propachlor, one or more solid, water-soluble pesticide components. Water soluble components have a solubility greater than 2000 ppm. In such composition, the soluble pesticide will of course be in solution in water as the con-tinuous phase. Other suitable active herbicides inelude dieamba, i.e., 2,5-diehloro-6-methoxy benzoie aeid and amine salts thereof as well as sparingly soluble esters; 2,4-dichlorophenoxyacetic acid and ; amine salts thereof as well as the sparingly soluble butoxyethanol ester; bifenox and linuron as well as i the aforementioned herbicidal triazines. Sparingly soluble compounds are those having a solubility below 1500 ppm and preferably below 200 ppm.
The three-way eombination o~ heteropolysae-eharide gum, the surfactant or surfactants and the dispersant employed in combination comprise an important dispersing-suspending system in an important embodiment of the flowable pesticide composition of this inven-tion. It is critical to employ these components in eertain prescribed ratios both in relation to each other and to the concentration of pesticide component~
in order to obtain compositions with the desired storage stability and water dispersibility.
18,246A-F -7-.
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In another preferred embodiment, the gum is substantially or entirely omitted, while the relative proportion of surfactant is increased in preparing higher propachlor solids compositions containing 5 or more pounds propachlor per gallon. In such embodiment in which the propachlor or propachlor-triazine com-ponent or other solids mixture is relatively high and the gum is largely or entirely omitted, the surfactant and dispersant serve as the dispersing suspending system.
The terms "heteropolysaccharide" and "hetero-polysaccharide gum" as used-herein are meant to include the use of the polysaccharide in the form of the colloid and its salts, e.g. amine derivatives prepared by the method disclosed for example in U.S. Patent 3,244,595.
The heteropolysaccharde which is commonly designated in the art as the xanthan gum is a high molecular weight linear cellular material prepared by the action o~ bacteria of the genus Xanthomonas on carbohydrates.
It has a molecular weight in excess of 200,000, pre-ferably over one million. A variety of carbohydrates can be fermented with various species of this genus Xanthomonas to produce the heteropolysaccharide.
Examples of suitable bacterium species of the genus Xanthomonas include X. campestris, X. carothee, X. inconue, X. begoniae, X. malvacerum, X. vesicatoria, _ translucens, and X. vaculorum, among others.
Suitable carbohydrates include, glucose, sucrose, fructose, maltose, lactose, galactose, soluble starch, corn starch, potato starch, and the like. Preparation of heteropolysaccharides suitably used herein is described in greater detail but not solely in U.S.
18,246A-F o8_ Patent 3,020,~06. It is to be understood that neither the heteropolysaccharides per se nor their preparation consitute a part of the present invention.
The surfactant system employed in the sus-pending-dispersing system of the flowable composition of this invention is either a b:Lend of anionic and nonionic surfactants or composed entirely of either a nonionic surfactant or an anionic surfactant. A
blend consisting of up to 4 parts nonionic per part anionic surfactant is treated or used in the same manner as anionic surfactant, while a blend consis-ting of more than 4 parts nonionic per part o~
anionic surfactant is treated or used in the same manner as nonionic surfactant used as sole dispersant.
Specific suitable anionic surfactants are selected from the following classes or types of materials:
ethoxylated monohydric sulfated alcohol salts of sodium, potassium, alkaline earth metals, ammonium, alkyl amines, alkanolamines or blends thereof (also 20 designated in the art as alkyl polyether alcohol ;
sulfates); ethoxylated sulfated alkylphenol salts of sodium, potassium, alkaline earth me-tals, ammonium, alkyl amines, or alkanolamines or blends thereof (also designated in the art as alkylaryl polyether alcohol sulfates); and the sodium, potassium, alkaline earth metal, or ammonium salts of alkyl phenoxybenzene disulfonates.
Specific suitable nonionic surfactants are selected from the following classes or types of non-ionic surfactant materials: ethoxylated alkyl phenols(also designated in the art as alkylaryl polyether alcohols); ethoxylated aliphatic alcohols (or alkyl ~polyether alcohols); ethoxylated fatty acids (or .
18,246A-F 9- ~i . ~
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polyoxyethylene fatty acid esters); ethoxylated anhydrosorbitol esters (or polyethylene sorbitan fatty acid esters); ethoxylated polyoxypropylene glycols (polyalkylene oxide block copolymers);
ethoxylated polyoxypropylene monohydric alcohols (polyalkylene oxide block copolymers of monohydric alcohols); and ethoxylated polyoxypropylene alkyl phenols (polyalkylene oxide block copolymers of alkyl phenols).
. Of these the preferred surfactants are a blend of:
(a) (1) ethoxylated monohydric alcohol, i.e., alkyl polyether alcohol sulfates of the general formula:
+
C10 to C15 linear or branched chain alkyl group, y is an integer of from 2 to 19 and M is a cation selected from ammonium, calcium, magnesium, potassium, sodium and zinc;
(2) ethoxylated, sulfated alkyl phenols, i.e., alkylaryl polyether alcohol sulfates of the . general formula:
R ~ o-(cH2cH2o)y-cE2cH2oso3 M
wherein R is a C8 to C12 linear or branched chain alkyl, y is an integer of 3 to 13 and M is a 25 - cation selected from ammonium,- calcium, magnesium, potassium, sodium and zinc; alone or in admixture with one or more of the following nonionic surfactants:
18,246A-F ~10-:; ., i. :
(b) (1) ethoxylated polyoxypropylene glycols, i.e., polyalkylene oxide block copolymers of the general formu]a:
HOCH2 C~I2 O- ( CH2 CH20 ) X- ( C3H6 ) y wherein x is an integer of from 5 to 95 and y is an integer from 5 to 150 and the average molecular weight of the copolymer is in the range of 1800 to 9000;
(2) ethoxylated polyoxypropylene monohydric alcohols, i.e., polyalkylene oxide block copolymer of mononydric alcohols of the general formula:
R-ocH2cH2o-(cH2cH2o)x (c3H6o)y wherein R is a Cl to C8 linear or branched - chain alkyl group, x is an integer of from 5 to-70 y is an integer of from 5 to 55 and the average molecular weight of the copolymer is in the range of 2400 to 3500; and (3~ ethoxylated polyoxypropylene alkyl phenol, i.e., polyalkylene oxide block copolymer of alkyl phenol of the general formula:
- R ~ (CH2CH2O)X-(C3H6O)y wherein R is a C8 to C12 linear or branched chain alkyl group, x is an integer of 30 to 60, y is an integer of 5 to 35, and the average molecular weight of the copolymer is about 3000.
.
Utilizing these surfactant systems, formula-tions are obtained with optimum water dispersibility and adequate storage stability. Within this class, `
especially preferred combinations of surfactants are 18,246A-F -11-.. , ~, , :. i - .I , ~ ~ . --.
... . . ~.: .. ~ - , ~12-any of (a) alkyl polyether alcohol sulfate wherein R is a C12 alkyl, y is an integer selected from 3 and 4 and M is sodium or ammonium; or alkylaryl polyether alcohol sul-fate wherein R is a C9 alkyl, y averages 3 and M is sodium or ammonium; with one or more of (b) polyalkylene oxide block copolymer wherein the weight percent of the polyoxyethylene units in the mo:Lecule range from 30 to 60 percent of the average molecular weight of the polymer;
polyalkylene oxide block copolymer of monohydric alcohol wherein R is a C4 alkyl; and polyalkylene oxide block copolymer of alkyl phenol wherein R is a Cg alkyl, the surfactants being otherwise as described in the general categories above.
In compositions containing a higher propachlor solids content, such as 40 to 60 percent by weight, the xanthan gum generally is employed in an amount ranging from 0.1 to 0.5 percent by weight; the surfactant in an amount ranging generally from 2 to 7 percent by weight;
and the dispersant in an amount ranging from 0.5 to 4 percent by weight, and most preferably in an amount ranging from 0.5 to 2 percent by weight. If each of these components were employed separately as the sole suspending or wetting agent in otherwise similar for-mulations, the troublesome solid pesticide component, i.e., propachlor, would soon settle out of the continuous water phase. ~epending upon the length of time allowed to stand after the settling of the solid, it would become increasingly difficult to resuspend the solids, even with vigorous and prolonged agitation.
In the pesticide composition of this inven-tion, it is necessary to employ each of the hetero-polysaccharide and surface active agent (or wetting 18,246A-F -12- -. .
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agent) and dispersant components within the ranges stated above in order to obtain the desired compo-sition properties. Formulations containing amounts of these components outside the stated ranges will either be too low or too high in viscosity and non-flowable, exhibiting inferior water dispersibility and unsatisfactory storage stability of the sus-pension concentrate.
In the pesticide composition of this inven-tion containing the heteropolysaccharide gum as well as dispersant and one of (a) an anionic surfactant, (b) a nonionic surfactant, or (c) both an anionic and a nonionic surfactant, it is necessary to employ each within the ranges stated hereinabove in order to assuredly obtain the desired composition properties.
- Formulations containing amounts of these components outside the stated ranges will either be too low in viscosity with a tendency to settle out solids or too high in viscosity and nonflowable, exhibiting inferior water dispersibility on dilution and unsatisfactory storage stability.
.
In concentrate compositions containing 5 pounds or more propachlor per gallon of concentrate, the composition tends to be thicker, i.e., more vis-cous, because of the higher solids content. This ispreferably overcome by reducing and/or altogether omitting the amount of heteropolysaccharide gum other-wise employed, while employing the surfactant at a concentration of at least 6 percent by weight, and 18,246A-F i13-, .
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.
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~14--preferably also increasing the dispersant to aneffective amount above 1 percent by weight, gen-erally to 2 percent by weight.
Compositions having viscosities ranying from 300 to 4500 centipoises (cps), and more preferably 700 to 3500 (cps), as measured with a Brookfield Viscometer, Model RVT (No. 3 Spindle - 10 rpm) gen-erally will exhibit the desired flowability char-acteristics. As preYiously mentioned, the hetero-polysaccharide gum and the described surfactantsand the dispersant, in combination, comprise one of the dispersing-suspending systems of the flowable propachlor compositions of this invention. In compositions containing higher propachlor content, such as, at least 50 percent by weight of propachlor, a desirable dispersing-suspending system contains more surfactant, more dispersant and little or no gum. These components must be ratioed properly to each other and to the propachlor concentration in order to obtain compositions with desirable storage stability and water dispersibility.
Thus, the ratio, by weight, of propachlor to the anticaking agent, or flow-aid, should be in the range of from 5.5 to 1 to 26 to 1. Nonionic surfactant may be omitted altogether but preferably is employed in a ratio of, by weight, 1 to 2 with respect to the amount of anionic surfactant in the composition. The dispersant should be used in an effective amount within the range herein recited as needed to obtain ready dispersibility of the solids on dilution in making a tank mix and as an inhibitor of crystal growth.
.
18,246A-F 14-,. . ~. , . ., .., . . . :.,::
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Also critical to the storage stability of these compositions is both the type and concentration of the inert carriers used in these formulations functioning as flow-aids or anticaking aids.
Numerous pesticidal dust diluents and car-riers are known to the art. The "Handbook of Insec-ticide Dust Diluents and Carriers" by T. C. Watkins and L. B. Norton, Dorland Books, Caldwell, New Jersey (1955) lists many of those commonly used in the trade for those purposes. We have found that many of those are also commonly used in the art for flowable pes-ticidal compositions that will not serve to maintain, in combination with the present suspending-dispersing system, the desired storage stability of the composition . 15 under extreme storage conditions. The suitable inert carriers are selected from the ball (China) clays such as Bandy Tan, Gleason, Stratton and Barden clays; the diatomites sold as, Celite~ 209 and Celatom~ MN-39;
and a finely divided synthetic precipitated hydrated silicon dioxide (silica) such as the silica sold under the trademarks or tradenames Cab-0-Sil~ and Hi-Sil~, e.g., Hi-Sil~ 233. Any of these are used alone or in combination. For optimum performance character-istics, a blend of a silica and a ball clay of the kaolinite group is preferred. In such a blend, the silica content can range from 5 to 95 percent by - weight of the combination with the preferred com-bination containing 25 to 75 weight percent silica and the balance the ball clay. The total composition, as indicated above, contains from 1 to 10 percent by weight of the anticaking or flow-aid. Preferably the total flowable composition contains from 3 to 8 percent by weight of the anticaking aid.
18,246A-F 15-,~ r ", ~ : . .. - . :
~ J~
The novel and highly essential component of the present suspension concentrate is a dis-persant which facilitates the dispersion or dilution of the suspension concentrate with water in the pre-paration of the final mix in the field, generally referred to as a tank mix. It should be noted that it may be possible to prepare an entirely satisfactory looking and performing suspension concentrate so far as can be ascertained in the concentrate form which is not at all satisfactory upon dilution as the solids tend to settle rapidly, and/or to agglomerate, especially when the tank mix is made up using hard water. It is therefore essential to include in the composition an adequate dispersant.
Even more importantly the dispersant is critical to concentrate stability under various storage conditions such as during freeze-thaw cycles which lead or tend to lead to crystal growth.
.. . ..
For purposes of the present description and the appended claims a disp~rsant is defined as a polar organic material with dispersant properties which does not lower the surface tension of water more than 30 percent from the normal 72 dynes per square centimeter in contrast to surfactants which lower surface tension of water 50 percent or more-.
'` ..:
Suitable dispersants are selected from the sodium, potassium, ammonium, calcium, magnesium or zinc salts of the commonly available lignosulfonic acids, the sodium salt being preferred, or, the poly-merized alkyl or alkylaryl sulfonic acid salts, suchas, the potassium, sodiurn, calcium or an~lonium salts, with the sodiurn salt bein~ preferred. A specific 18,246A-F 16-:.
r-j example of a suitable sodium salt of polymerized alkyl, alkylaryl or aralkyl sulfonic acid is:
Daxad~ 27, sodium salt of benzoid alkyl sulfonic acid.
The amount of dispersant used should be in the range of from 0.1 to 6 weight percent, with the preferred amount being in the range of 0.5 to 4 percent and the most preferred amount being 0.5 to 2 percent by weight. Functionally, the dispersant retards or preven-ts settling of the suspended solids and is believed to aid in the prevention or inhibition of crystal growth of the propachlor solids in the aqueous concentrate, as during freeze-thaw cycles.
Should the propachlor or other active herbicide employed in making the suspension concen~
trate of the invention contain acidic manufacturing contaminants causing a 10 weight percent water dis-persion thereof to e~hibit a p~ below 4, then compo-sitions to meet the objectives of this invention must contain somewhat more dispersant than stated above as may readily be determined by trial and error.
Below pH 1 the use of additional dispersant does not compensate adequately for the increased acidity.
Minor quantities of one or more additional compone~ts are preferably included in the composition to provide a highly useful and convenient, practical pesticide composition concentrate. A freezing point depressant is preferably incorporated into the compo-sition to ensure good formulation properties are maintined under adverse storage conditions such as low temperature conditions. A number of freezing point depressants known to the art may be used, 18,246A-F
. , , . . :
however, the best performance is obtained using from 2 to 10 percent by weight of a lower alkylene glycol, such as ethylene glycol or propylene glycol.
In order to facilitate preparation of a tank mix in the field without the formation of undue foam because of the presence of a surfactant and dispersant components hereof, it is highly useful to employ an antifoaming agent. The various commercially available silicone materials or emulsions such as Dow Corning Antifoam A~ are examples of suitable antifoaming agents which may be incorporated in the flowable concentrate in an amount ranging generally from ~.05 to 1 percent by weight of the total compo-sition. A specific example of an antifoaming agent is dimethylpolysiloxane.
It is also generally preferred to employ a preservative to prevent the growth of bacteria and/or fungi in the concentrate during storage. Any of a number of bactericides and fungicides may be employed that are compatible with the present system. A highly satisfactory preservative useable in the present invention is sodium ortho phenyl phenate sold under the trademark Dowicide~ A. Other suitable preservatives are formaldehyde and sodium pentachlorophenate.
Water is employed in sufficient amount ~o serve as the continuous phase for the dispersed pro-pachlor and to achieve reasonahle viscosity charac-teristics compatible with the need for supplying a concentrate with sufficient active solids content.
18,246A-F -18-~ . . , . , :
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In preferred compositions, i.e., those which incor-porate high concentrations of propachlor, from 20 to 40 percent by weight of water will generally be employed.
The order of addition of the ingredients is not especially critical to the preparation of the composition, although it is preferred to mix the heteropolysaccharide gum (if employed), the surfac-tant, the antifoam agent, the freezing point aid, any preservative employed, any soluble herbicide and the dispersant with the continuous water phase before adding the solid propachlor and other sparingly - soluble pesticide and the anticaking aid. The pre-paration is carried out at ambient -temperature with mild agitation, no heat or undue pressure being required to obtain a homogenous suspension. How-ever, in order to ensure that the pesticide ingredient will have the desired average particle size, it is necessary beforehand to subject the propachlor by itself or in combination with any of the above men-tioned ingredients to air milling, hammer milling, ball milling or other conventional comminuting treatment known to the art.
.
In combinations of propachlor and most any of the triazine herbicides previously employed as wettable powders, e.g., weight ratios of 2 to 3 parts propachlor per part of triazine have been generally suitable considering the relative dosage rate of each to be applied in the control of undesired vegetation.
The same ratios are desirably employed in preparing a flowable aqueous suspension concentrate of a pro-pachlor-triazine herbicide mixture according to the invention.
1~,246A-F -19-.
:
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The criteria set forth above for the pre-paration of flowable concentrates containing propachlor only are generally applicable to the preparation of flowable concentrates of the mixtures. The solids - 5 should be comminuted during some stage of preparation of the flowable concentrate to bring the insoluble solid herbicide to a fineness in the range o~ l to 10 microns average particle size in order that the solids are rather readily suspended initially.
The problems of propachlor remain because its solubility is just sufficiently high to create crystal growth possibilities on storage with atten-dant settling out and caking and finally dispersibility problems in the field when tank mixes are prepared.
The triazines of commercial interest are rather sparingly soluble in water. The principal triazines of interest include the s-triazine herbicides atrazine, i.e., 2-chloro-4-(ethylamino)-6-(isopropyl-amino)-s-triazine, having a reported solubility in water at 27C of 33 parts per million by weight (ppmw);
cyanazine, i.e., 2-[[4-chloro-6-(ethylamino)-s-triazin--2-yl]amino]-2-methylpropionitrile, having a reported solubility in water at 23C of 160 ppmw and at 25C
of 171 ppmw; propazine, i.e., 2-chloro-4,6-bis(iso-propylamino)-s-triazine, having a reported solubility in water at 20C of 8.6 ppmw; cyprazine, i.e., 2-chloro--4-(cyclopropylamino)-6-(isopropylamino)-2-triazine, having a reported solubility in water at 25C of 6.9 ppmw and at 40C of about 195 ppmw; and simazine, i.e., 2-chloro-4,6-bis(ethylamino)~s-triazine, having a reported solubility in water at 20C of 5 ppmw and at 85C of 84 ppmw;`and the as-triazine metribuzin, . .
18,246A-F -20-.
,. . . , ~. , ~.. ; . ,, ~ .
..
i.e., 4-amino-6-tert-butyl~3-(methylthio)-as-triazin--5(4H)one ha~ing a water solubility at 20C of 1220 ppmw.
Any of the triazine herbicidal compounds of commercial utility, such as the foregoing, and other sparingly soluble broadleaf herbicides may be combined with propachlor in the weight ratios indicated and in the preparation of an aqueous flowable sus-pension concentrate according to the invention and substantially in the manner described above for flowable concentrates containing propachlor only, achieving the advantages of stability, i.e., rela-tive freedom from serious adverse settling and caking on extended storage, and good dispersibility charac-teristics on preparing tank mixes, even with hard oralkaline waters.
In preparing a flowable concentrate of propachlor and triazine mixture, the total amount - - -of herbicidal solids suspended is in the range of propachlor solids suspended as described hereinabove.
Thus, a 4 pound gallon of the combination of propachlor and a triazine suitably contains, by way of illustration 2.88 pounds of propachlor and 1.12 pounds of triazine, such as atrazine, in one embodiment and 3 pounds of propachlor and 1 pound of triazine in another embodiment.
Similarly, a 5 pound gallon of the combination of propachlor and a triazine such as propazine suitably contains, by way of illustration, 3.6 pounds of pro-pachlor and 1.4 pounds of propazine.
In preparing a flowable concentrate of pro-pachlor and at least one other broadleaf herbicide 18,246A-F 21-.:
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wherein a triazine is not included unless there is more than one additional broadleaf herbicide, the composition contains at least 30 percent by weight propachlor and is one in which problems of storage stability and final dispersibility as a tank mix are encountered unless prepared according to this invention.
~.
The following examples serve to illustrate the invention and not to limit the claims thereof.
Example l A flowable aqueous suspension concentrate of propachlor is prepared having the following composition:
~eight Ingredients Percent 15 Propachlor-tech. grade (95% active) 43.95 Hi-Sil~ 233 hydrated precipitated silica 1.80 Bandy Tan clay 3.59 p-Nonylphenoxy ethoxylated ethanol sulfate, ammonium salt 2.00 20 Ethoxyiated polyoxypropylene butanol 4.00 Antifoam A~ (dimethylpolysiloxane) 0.25 Kelzan heteropolysaccharide gum (Galaxy XB~ is equivalent) 0.12 Ethylene glycol 5.00 -25 Polyfon H~ lignosulfonate salt 1.00 Water Balance .
18,246A-F -22-.' ' : ' . " ' ' ', '" ' ` , ` ' ~ ' ' "'`~ . ~ '' i '`, ''. ' In general, it is preferred to add the pre-scribed amounts of surfactant and ethylene glycol, such as those set forth above, to the water. This is followed by the lignosulfonate salt and the antifoam ingredient. The heteropolysaccharide gum is normally added as a 2 percent by weight aqueous solution pre-viously prepared or premixed. The foregoing ingre-dients are all added while mixing of the composition continues and with continued agitation, the clay, silica and propachlor are incorporated into the solution. This homogenous composition or suspension is then subjected to one of the conventional com-minuting treatments known in the art, preferably sand milling, to assure that the propachlor solid will have the desired average particle size pre-ferably between 1 and 10 microns average diameter.
The so-prepared composition appears grayish opaque in color. It has a Brookfield viscosity at 23C of 1100 to 1200 cps as determined at 10 rpm. The pH is in the range of 5.5 to 6.5. The specific gravity is 1.15 grams per cc. The concentration of the pesti-cide is 4 pounds active ingredient per gallon.
The formulation is of quite thin consistency and pours easily. When poured into water it exhibits excellent bloom spreading out uniformly into the water and good dispersibility, i.e., no settling of solids.
The medium particle size of the propachlor is 4 to 8 microns with 98~2 percent being less than 20 microns average diameter. Upon dilution of 1 part formulation concentrate per 99 parts water (alkaline 300 ppm water and 100 ppm, 500 ppm and 1000 ppm calcium hard-ness, respectively) there is less than 0.1 milliliter of sediment after one hour in each of the ~ilutions 18,246A-F -23-.
. . , :'- :: ;: - ' .
so prepared. Redispersibility of sediment after 24 hours was good. The formulation shows good physical and chemical stability under accelerated tempera~ure storage at 50C. After more than three months storage at 50C, the formulation shows no significant loss in the active assay, only little liquid separation which readily redisperses to a homogenous suspension on shaking, no gelling, sediment or tendency to agglomerate or become thixotropic. The formulation has passed 10 freeze-thaw cycles (two per week) with no lumps, agglomeration or sediment visible, very little liquid separation which easily redisperses on shaking to a free-flowing homogenous suspension.
Example 2 15 A flowable aqueous suspension concentrate of propachlor was prepared having the ~ollowing composition:
Weight Inaredients Percent -20 Propachlor-tech. grade (about 95% active)57.9 Hi-Sil~ 233 precipitated silica 2.23 Bandy Tan Clay 2.23 p-Nonylphenoxy ethoxylated ethanol sulfate, ammonium salt 2.0 25 Ethoxylated polyoxypropylene butanol 4.0 Antifoam A~ 0.2 Polyfon H~ sodium lignosulfonate 1.5 Ethylene glycol 3.0 Water Balance 18,246A-F -2~-.
~, .
~25-On preparation of the foregoing composition in a manner similar to that described for Example l, the following physical properties were noted:
The so-prepared composition appears grayish opaque in color. It has a Brookfield viscosity at 23C of 3100 cps as determined at 10 rpm. The pH
is in the range of 5.5 to 6.5. The specific gravity is 1.114 grams per cc. The concentration of the pesticide concentration is 5.22 pounds active ingre-dient per gallon.
The formulation pours easily and when pouredinto water exhibits excellent bloom. ~he median par-ticle size of the propachlor is well within the range of 1 to 10 microns. Upon dilution of l part formula-tion concentrate per 99 parts water in several testsusing water of 100 to lQ00 ppm calcium hardness, there is less than 0.1 milliliter of sediment after one hour in each of the dilutions prepared.
The formulation on accelerated temperature ;
20 storage at 50C for more than three months showed no , significant loss in the active assay, only little liquid separation which readily redispersed to a homogenous suspension on shaking, no gelling, sedi-ment or tendency to agglomerate or become thixotropic.
The formulation has passed 10 freeze-thaw cycles (two per week) with no lumps, agglomerate or sediment - visible, very littie liquid separation which easily redispersed on shaking to a free-flowing homogenous -suspension.
18,246~-F -25-.
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Examples 3 and 4 Flowable aqueous suspension concentrates of propachlor were prepared according to the invention from a purified grade propachlor using substantially the procedure of Example 1 wherein comminution is carried out using a ceramic kall mill with ceramic balls for 24 hours. Each concentrate contained by weight 0.12 percent Galaxy XB~ heteropolysaccharide gum with an average molecular weight greater than 200,000; 0.2 percent Polyfon H~ sodium lignosulfonate;
0.45 percent Dow-Corning Antifoam B~, an alkylpoly siloxane; 2 percent of Steol~ 4N sodium lauryl ether sulfate and 2 percent of Terric~ 200 polyalkylene oxide (ethylene oxide-propylene oxide) copolymer of nonylphenyl, 41.8 percent by weight propachlor, 5 per-cent by weight ethylene glycol; in addition to anti-caking agent and the balance water. The antical~ing , agent used in the proportions thereo~ are set forth in Table 1, along with "initial viscosity" values.
"I~itial viscosity" values are determined when the concentrate is freshly prepared. If the initial viscosity does not fall within the range of about 20 to about 3500 as determined at about 25C
with a Brookfield Viscometer, Model RVT (No. 3 spindle - 10 rpm), the composition, especially if somewhat more viscous, may be stable and redispersible but is sufficently hard to handle to be of little or no commerical interest and is therefore outside the scope of this invention.
Test portions of each of the compositions of Examples 3 and 4 remained satisfactory after being subjected to 10 freeze-thaw cycles in one test and 18,246A-F -26-.: . - --, . .
a.3 to at least three months accelerated storage at 50C, showing little or no settling and exhibiting ready dispersability in water to a dilution of 1 to 99 by volume.
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Similar ~ine results like those achieved in Examples 3 and 4 are obtained using Hi-Sil~ 233 alone in place of Bandy Tan clay in the amounts there employed.
Examples 5-8 Flowable aqueous suspension concentrates of propachlor were prepared according to the invention from a purified grade propachlor using substantially the procedure of Example l and wherein the comminution to 1-10 microns was carried out using a ceramic ball mill with ceramic balls and milling for 24 hours to reduce the propachlor particle size to an average value in the range of 1 to lO microns. Each concen-trate contained, by weight, 41.8 percent propachlor,
3.53 percent Bandy Tan clay, 1.77 percent Hi-Sil~ 233 precipitated hydrated silica, 0.45 percent Dow-Corning Antifoam C~, 0.20 percent Polyfon H~, 0.12 percent Galaxy XB~ xanthan gum, 5 percent ethylene glycol, a trace of preservative, 4 to 6 percent of surfactant, and the balance water. A comparison composition containing only nonionic surfactant was similarly prepared.
` ~ach composition was tested~for dispersibility by diluting one part concentrate in 99 parts water, stirring rapidly ~1700 rpm~ for one minute and allowing to stand undisturbed in a 100 ml graduated tube. The amount of sedimentation was read in milliliters (ml) after one hour. In respective tests of each concen-trate, the 99 parts water contained: 300 ppm caustic, expressed as ppm Na; lO0 ppm, 500 ppm and lO00 ppm, respectively Ca++.
18,246A-F -29-.
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The surfactants and the amounts thereof employed, initial viscosities and pH readings as well as sedimentation test results are tabulated in Table 2. A large amount of sedimentation is noted in the comparison concentrate in which no anionic surfactant was employed.
Each concentrate was also subjected to freeze-thaw cycles and accelerated storage at 50C.
Each concentrate appeared satisfactory after 10 freeze-thaw cycles except Example 8 which showed agglomeration after six cycles. All of the concen-trates appeared stable after three months accelerated storage. The concentrate of Example 6 exhibited slight agglomeration which did not appear to inter-fere with ready dispersion.
18,246A-F -30-:
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Example 9 When the comparison run described in Table 2 is repeated using 1.2 percent Polyfon H~ instead of 0.2 percent by weight the suspension concentrate is stable on storage with freeze-thaw cycles during at least 12 weeks and the concentrate is readily dis-persible in hard water at any time during the storage test.
Examples 10 and 11 Flowable aqueous suspension concentrates of propachlor were prepared substantially as in Examples 5-3 except that comminution was with an Attritor operated for 90 minutes at 270-370 rpm using 1/8 inch diameter 440 C stainless steel balls. Dow-Corning Antifoam A~ in a proportion of 0.25 percent by weight was used instead of Antifoam C~, and the amount of Polyfon H~ in each case was 1.0 percent by weight.
In the case of Example 10, the surfactant was 2 percent by weight Witcolate~ 1075X plus 4 weight percent Witconol NS~ 500K, 0.25 percent by weight of Dow-Corning Antifoam A~ was used in place of iAntifoam C~, and the initial viscosity at 23C was 1200 cps and the pH was 6.2.
In Example 11, the same surfactant blend was used as in Example 10, the initial viscosity was 1100 and the pH was 5.4.
On subjecting both concentrates to the sedimentation test used in the testing of Examples 5-8, very little sedimentation, 0.01-0.07 ml, was observed. Samples of both concentrates showed no .
18,246A-F ~33- -.
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7'-~j agglomeration or other instability after 10 freeze--thaw cycles and were stable and readily dispersible after three months accelerated storage at 50C.
Example 12 ~ flowable aqueous suspension concentrate of propachlor was prepared as i.n Example 10 except that the dispersant used was Daxad~ 27 brand sodium salt of benzoid alkyl sulfonic acid. The initial viscosity at 23C was 1400 cps and the pH was 5.5.
On subjecting the concentrate to the sedi-mentation test used in the testing of Examples 5-8, sedimentation was not mroe then 0.04 ml except in the case of the 1000 ppm Ca water, in which case O.25 ml was observed, indicating overall quite good dispersibility in hard waters.
The concentrate showed good stability after 10 freeze-thaw cycles and also after three months accelerated storage at 50C.
Similar fine results to the foregoing examples are obtained using anionic surfactants of each of the classes set forth hereinabove alone or in combination with any of the classes of nonionic surfactants set forth or nonionic surfactants in the proportions described above with sufficient dispersant employed.
In each of the examples described above, the xanthan gum used contained about 1.7 percent Dowicide A~ preservative to provide about 1000 ppm preservative in the finished concentrate.
18,246A-F -34-~ : . . : . . ~ :
Exam~le 13 As an example of flowable aqueous suspension concentrate of a mixture of propachlor and atrazine, a composition having the following listed components was prepared substantially according to Example 1 except that the herbicidal ingredients propachlor and atrazine were added simultaneously.
ComponentWeight Percent Propachlor 30.40 10 Hi-Sil~ 233 1.80 Bandy Tan Clay 3.59 Atrazine 11.36 Witconol NS~ 500 K (Witco) 6.00 Antifoam A~ 0.10 15 2% Galaxy XB~-23* 5.89 Daxad~ 27 1.00 Propylene Glycol 4.00 Water + Inerts 35.86 100.00 -*Contains 1000 ppm Dowicide A~ on total formulatio~ basis. There is 1.7 perce~t Dowicide A in the 2 percent Galaxy XB~-23.
The resulting composition had initial viscosities as follows:
` ~ach composition was tested~for dispersibility by diluting one part concentrate in 99 parts water, stirring rapidly ~1700 rpm~ for one minute and allowing to stand undisturbed in a 100 ml graduated tube. The amount of sedimentation was read in milliliters (ml) after one hour. In respective tests of each concen-trate, the 99 parts water contained: 300 ppm caustic, expressed as ppm Na; lO0 ppm, 500 ppm and lO00 ppm, respectively Ca++.
18,246A-F -29-.
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The surfactants and the amounts thereof employed, initial viscosities and pH readings as well as sedimentation test results are tabulated in Table 2. A large amount of sedimentation is noted in the comparison concentrate in which no anionic surfactant was employed.
Each concentrate was also subjected to freeze-thaw cycles and accelerated storage at 50C.
Each concentrate appeared satisfactory after 10 freeze-thaw cycles except Example 8 which showed agglomeration after six cycles. All of the concen-trates appeared stable after three months accelerated storage. The concentrate of Example 6 exhibited slight agglomeration which did not appear to inter-fere with ready dispersion.
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Example 9 When the comparison run described in Table 2 is repeated using 1.2 percent Polyfon H~ instead of 0.2 percent by weight the suspension concentrate is stable on storage with freeze-thaw cycles during at least 12 weeks and the concentrate is readily dis-persible in hard water at any time during the storage test.
Examples 10 and 11 Flowable aqueous suspension concentrates of propachlor were prepared substantially as in Examples 5-3 except that comminution was with an Attritor operated for 90 minutes at 270-370 rpm using 1/8 inch diameter 440 C stainless steel balls. Dow-Corning Antifoam A~ in a proportion of 0.25 percent by weight was used instead of Antifoam C~, and the amount of Polyfon H~ in each case was 1.0 percent by weight.
In the case of Example 10, the surfactant was 2 percent by weight Witcolate~ 1075X plus 4 weight percent Witconol NS~ 500K, 0.25 percent by weight of Dow-Corning Antifoam A~ was used in place of iAntifoam C~, and the initial viscosity at 23C was 1200 cps and the pH was 6.2.
In Example 11, the same surfactant blend was used as in Example 10, the initial viscosity was 1100 and the pH was 5.4.
On subjecting both concentrates to the sedimentation test used in the testing of Examples 5-8, very little sedimentation, 0.01-0.07 ml, was observed. Samples of both concentrates showed no .
18,246A-F ~33- -.
`: :
t ..
7'-~j agglomeration or other instability after 10 freeze--thaw cycles and were stable and readily dispersible after three months accelerated storage at 50C.
Example 12 ~ flowable aqueous suspension concentrate of propachlor was prepared as i.n Example 10 except that the dispersant used was Daxad~ 27 brand sodium salt of benzoid alkyl sulfonic acid. The initial viscosity at 23C was 1400 cps and the pH was 5.5.
On subjecting the concentrate to the sedi-mentation test used in the testing of Examples 5-8, sedimentation was not mroe then 0.04 ml except in the case of the 1000 ppm Ca water, in which case O.25 ml was observed, indicating overall quite good dispersibility in hard waters.
The concentrate showed good stability after 10 freeze-thaw cycles and also after three months accelerated storage at 50C.
Similar fine results to the foregoing examples are obtained using anionic surfactants of each of the classes set forth hereinabove alone or in combination with any of the classes of nonionic surfactants set forth or nonionic surfactants in the proportions described above with sufficient dispersant employed.
In each of the examples described above, the xanthan gum used contained about 1.7 percent Dowicide A~ preservative to provide about 1000 ppm preservative in the finished concentrate.
18,246A-F -34-~ : . . : . . ~ :
Exam~le 13 As an example of flowable aqueous suspension concentrate of a mixture of propachlor and atrazine, a composition having the following listed components was prepared substantially according to Example 1 except that the herbicidal ingredients propachlor and atrazine were added simultaneously.
ComponentWeight Percent Propachlor 30.40 10 Hi-Sil~ 233 1.80 Bandy Tan Clay 3.59 Atrazine 11.36 Witconol NS~ 500 K (Witco) 6.00 Antifoam A~ 0.10 15 2% Galaxy XB~-23* 5.89 Daxad~ 27 1.00 Propylene Glycol 4.00 Water + Inerts 35.86 100.00 -*Contains 1000 ppm Dowicide A~ on total formulatio~ basis. There is 1.7 perce~t Dowicide A in the 2 percent Galaxy XB~-23.
The resulting composition had initial viscosities as follows:
4 rpm 2250 cps 10 rpm 1200 cps 20 rpm 775 cps 18,246A-F ~35-,: c !
The specific gravity of the composition was 1.153, thus providing a 4 pound gallon containing 2.9 pounds propachlor and 1.1 pounds atrazine.
The composition is stable on long storage and is readily dispersible in water, including hard waters.
Example 14 As an example of a flowable aqueous suspen-sion concentrate of a mixture of propachlor and atra-zine, a composition having the following listed com-ponents was prepared substantially according to Examples 1 and 13.
ComponentWeight Percent Propachlor 30.40 .
~i-Sil~ 233 1.80 Bandy Tan Clay 3.59 Atrazine 11.36 Pluraflo E~ ~Wyandotte) 6.00 2% Galaxy XB~-23* 0.10 Daxad~ 27 5.89 Antifoam A~ 1.00 Ethylene Glycol 4.00 Water + Inerts 35.86 100 . 00 *Contains 1000 ppm Dowicide A~ on total for-mulation b~sis. There is 1.7 percent Dowicide A in the 2 percent Galaxy XB~-23.
18,246A-F ~36-~: ;
.
:
: .: - : .; : .,.
, ~ - . ~ .
.
~. ~3 7~S
The resulting composition had initial viscosities as follows:
4 rpm 1875 cps 10 rpm 950 cps 520 rpm 625 cps The specific gravity of the composition was 1.154, providing a 9.60 pound gallon containing 2.9 pounds propachlor and 1.1 pounds atrazine.
The composition is stable on long storage with substantially no settling and very little bleed and is readily dispersible in water, including hard waters.
Similarly excellent results compared to those in Examples 13 and 14 are obtained in sub-stituting any of cyanazine, i.e., 2-[[4-chloro-6--(ethylamino)-s-triazin-2-yl]amino]-2-methylpro-pionitrile; propazine, i.e., 2-chloro-4~6-bis(isopro-pylamino)-s-triazine; simazine, i.e., 2-chloro-4,6--bis(ethylamino)-s-triazine; cyprazine; or metribuzin for the atrazine in said examples.
Also similarly excellent results compared to those in Examples 13 and 14 are obtained on sub-stituting mixtures of propachlor with any of dicamba, bifenox, linuron or butoxyethanol ester of 2,4-D with at least 30 percent by weight propachlor in the con-centrate for the propachlor-atrazine mixtures as set forth in the above examples.
.
The composition of this invention, even if containing a high concentration of propachlor pro-30 . vides to the routineer an easily flowable formulation 18,246A-F 37-which utilizes water as the sole inexpensive dispersion medium. The present composition has excellent bloom characteristics, i.e., it is totally dispersible when added to water, even hard water. It can be diluted with water in all proportions to provide agglomerate-free, sprayable pesticide compositions of any desired toxicant concentration. The propachor particles in the suspension concentrate substantially do not undergo crystal growth during accelerated storage for a minimum of 12 weeks at 50C, so that on undergoing freeze-thaw cycles for a minimum of 12 weeks the composition sub-stantially does not settle out. Such a composition is expected to have a normal shelf life of 18 to 24 months or more. Preparation of the spray formulation may be easily accomplished at the application site by simply pouring an appropriate amount of the concentrated com-position into water within the spray tank or other convenient container. It is also possible to apply the composition in undiluted form, utilizing newer, specialized spray techniques.
The sprayable, agglomerate-free pesticide compositions formulated from the present composition may be applied from all types of presently used spray e~uipment with no plugging of the spray nozzles or other malfunction of the spray e~uipment.
18,246A-F -38-~ , i -' - ' ,:'' .'.` ~ :
:"' :', - : -. ~:
.
The specific gravity of the composition was 1.153, thus providing a 4 pound gallon containing 2.9 pounds propachlor and 1.1 pounds atrazine.
The composition is stable on long storage and is readily dispersible in water, including hard waters.
Example 14 As an example of a flowable aqueous suspen-sion concentrate of a mixture of propachlor and atra-zine, a composition having the following listed com-ponents was prepared substantially according to Examples 1 and 13.
ComponentWeight Percent Propachlor 30.40 .
~i-Sil~ 233 1.80 Bandy Tan Clay 3.59 Atrazine 11.36 Pluraflo E~ ~Wyandotte) 6.00 2% Galaxy XB~-23* 0.10 Daxad~ 27 5.89 Antifoam A~ 1.00 Ethylene Glycol 4.00 Water + Inerts 35.86 100 . 00 *Contains 1000 ppm Dowicide A~ on total for-mulation b~sis. There is 1.7 percent Dowicide A in the 2 percent Galaxy XB~-23.
18,246A-F ~36-~: ;
.
:
: .: - : .; : .,.
, ~ - . ~ .
.
~. ~3 7~S
The resulting composition had initial viscosities as follows:
4 rpm 1875 cps 10 rpm 950 cps 520 rpm 625 cps The specific gravity of the composition was 1.154, providing a 9.60 pound gallon containing 2.9 pounds propachlor and 1.1 pounds atrazine.
The composition is stable on long storage with substantially no settling and very little bleed and is readily dispersible in water, including hard waters.
Similarly excellent results compared to those in Examples 13 and 14 are obtained in sub-stituting any of cyanazine, i.e., 2-[[4-chloro-6--(ethylamino)-s-triazin-2-yl]amino]-2-methylpro-pionitrile; propazine, i.e., 2-chloro-4~6-bis(isopro-pylamino)-s-triazine; simazine, i.e., 2-chloro-4,6--bis(ethylamino)-s-triazine; cyprazine; or metribuzin for the atrazine in said examples.
Also similarly excellent results compared to those in Examples 13 and 14 are obtained on sub-stituting mixtures of propachlor with any of dicamba, bifenox, linuron or butoxyethanol ester of 2,4-D with at least 30 percent by weight propachlor in the con-centrate for the propachlor-atrazine mixtures as set forth in the above examples.
.
The composition of this invention, even if containing a high concentration of propachlor pro-30 . vides to the routineer an easily flowable formulation 18,246A-F 37-which utilizes water as the sole inexpensive dispersion medium. The present composition has excellent bloom characteristics, i.e., it is totally dispersible when added to water, even hard water. It can be diluted with water in all proportions to provide agglomerate-free, sprayable pesticide compositions of any desired toxicant concentration. The propachor particles in the suspension concentrate substantially do not undergo crystal growth during accelerated storage for a minimum of 12 weeks at 50C, so that on undergoing freeze-thaw cycles for a minimum of 12 weeks the composition sub-stantially does not settle out. Such a composition is expected to have a normal shelf life of 18 to 24 months or more. Preparation of the spray formulation may be easily accomplished at the application site by simply pouring an appropriate amount of the concentrated com-position into water within the spray tank or other convenient container. It is also possible to apply the composition in undiluted form, utilizing newer, specialized spray techniques.
The sprayable, agglomerate-free pesticide compositions formulated from the present composition may be applied from all types of presently used spray e~uipment with no plugging of the spray nozzles or other malfunction of the spray e~uipment.
18,246A-F -38-~ , i -' - ' ,:'' .'.` ~ :
:"' :', - : -. ~:
.
Claims (30)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Flowable aqueous suspension concentrate compositions which consist essentially of, by weight:
from 30 to 60 percent of particulate 2-chloro--N-isopropylacetanilide having a particle size mainly in the range of 1 to 10 microns;
from 1 to 10 percent of (a) an anionic surfac-tant, (b) a nonionic surfactant or (c) a mixture consisting of an anionic surfactant and a nonionic surfactant;
up to 1.0 percent of a heteropolysaccharide gum;
from 1 to 10 percent of an anticaking agent selected from the group consisting of a ball clay, a diatomaceous earth, a finely divided precipitated hydrated silica, and a mixture of any such clay or diatomaceous earth with finely divided precipitated hydrated silica;
up to 1.0 percent of an antifoaming agent;
and the balance substantially water;
the composition essentially having a viscosity at 25°C of 200 to 3500 cps; characterized by containing:
from 0.1 to 6 percent of a dispersing agent with the proviso that when the surfactant is nonionic surfactant or a mixture of anionic surfactant and non-ionic surfactant containing more than four parts nonionic surfactant per part of anionic surfactant the proportion of dispersing agent is at least 1 percent by weight.
18,246A-F -39-
from 30 to 60 percent of particulate 2-chloro--N-isopropylacetanilide having a particle size mainly in the range of 1 to 10 microns;
from 1 to 10 percent of (a) an anionic surfac-tant, (b) a nonionic surfactant or (c) a mixture consisting of an anionic surfactant and a nonionic surfactant;
up to 1.0 percent of a heteropolysaccharide gum;
from 1 to 10 percent of an anticaking agent selected from the group consisting of a ball clay, a diatomaceous earth, a finely divided precipitated hydrated silica, and a mixture of any such clay or diatomaceous earth with finely divided precipitated hydrated silica;
up to 1.0 percent of an antifoaming agent;
and the balance substantially water;
the composition essentially having a viscosity at 25°C of 200 to 3500 cps; characterized by containing:
from 0.1 to 6 percent of a dispersing agent with the proviso that when the surfactant is nonionic surfactant or a mixture of anionic surfactant and non-ionic surfactant containing more than four parts nonionic surfactant per part of anionic surfactant the proportion of dispersing agent is at least 1 percent by weight.
18,246A-F -39-
2. Composition of Claim 1 wherein the 2-chloro--N-isopropylacetanilide content is in the range of 40 to 60 percent.
3. Composition of Claim 1 or 2 wherein the proportion of dispersing agent is in the range of 0.5 to 4 percent by weight.
4. Composition of Claim 1 or 2 wherein the proportion of dispersing agent is in the range of 0.5 to 2 percent by weight.
5. Composition of Claim 1 or 2 wherein the surfactant is selected from anionic surfactant and a mixture of no more than four parts nonionic surfactant per part of anionic surfactant and the proportion of dispersing agent is in the range of 0.5 to 2 percent by weight.
6. Composition of Claim 1 wherein the propa-chlor content is less than 50 percent and the heteropoly-saccharide gum content is in the range of 0.02 to 1.0 percent.
7. Composition of Claim 1 wherein the ratio of propachlor to the anticaking aid is in the range of 5.5 to 26 parts by weight 2-chloro-N-isopropylacetanilide per part of anticaking aid.
8. Composition of Claim 7 wherein the anti-caking aid is a blend of silica and ball clay 18,246A-F -40-containing from 1/3 to 1 part by weight silica per part of the clay.
9. Composition of Claim 1 wherein there is employed from 1 to 10 percent of a mixture of an anionic surfactant and a nonionic surfactant, the amount of nonionic surfactant being from 0.1 to 4 parts by weight per part of anionic surfactant.
10. Composition of Claim 1 wherein the heteropolysaccharide gum is a xanthan gum having an average molecular weight of at least 200,000.
11. Composition of Claim 1 wherein the anticaking agent is Bandy Tan clay admixed with up to 50 percent by weight finely divided precipitated hydrated silica.
12. Composition of Claim 1 wherein the dispersing agent is selected from lignosulfonate salts in which the cation is selected from sodium, potassium, ammonium, calcium, magnesium and zinc and polymerized alkyl sulfonic acid salts and polymerized alkylaryl sulfonic acid salts in which the cation is potassium, sodium, calcium or ammonium.
13. Composition of Claim 1 containing, in addition, from 2 to 15 percent of a freezing point depressant.
14. Composition of Claim 9 wherein the surfactant employed is selected from the group con-sisting of a mixture of any one or more of (a) alkyl polyether alcohol sulfate, alkylaryl polyether alcohol sulfate and alkyl phenoxybenzene disulfonates with 18,246A-F -41-any one or more of (b) alkylaryl polyether alcohol, alkyl polyether alcohol, polyoxyethylene fatty acid ester, polyethylene sorbitan fatty acid ester, poly-alkylene oxide block copolymer, polyalkylene oxide block copolymer of monohydric alcohol and polyalkylene oxide block copolymer of alkyl phenols.
15. Composition of Claim 14 wherein the surfactant employed is selected from the group con-sisting of a mixture of either of (a) alkyl polyether alochol sulfate of the formula R-O-(CH2CH2O)y-CH2CH2OSO3-M+
wherein R equals a C10 to C15 linear or branched chain alkyl; y equals an integer of from 2 to 19; and M equals ammonium, calcium, magnesium, potassium, sodium and zinc; and alkylaryl polyether alcohol sulfate of the formula wherein R equals a C8 to C12 linear or branched chain alkyl; y is an integer of from 3 to 13; and M equals ammonium, calcium, magnesium, potassium, sodium and zinc; with one or more of (b) polyalkylene oxide block copolymer of the formula HOCH2CH2-O-(CH2CH2O)x-(C3H6O)y-H
where x is an integer of from 5 to 195; and y is an integer of from 5 to 150; and the average molecular weight of the copolymer is in the range of 1800 to 9000; and polyalkylene oxide block copolymer of monohydric alcohol of the formula:
18,246A-F -42-R-O-CH2CH2O-(CH2CH2O)y-(C3H6O)y-H
wherein R equals a C1 to C8 linear or branched chain alkyl; x equals an integer of from 5 to 70; y equals an integer of from 5 to 55; and the average molecular weight of the copolymer is in the range of 2400 to 3500; and polyalkylene oxide block copolymer of alkyl phenol of the formula:
wherein R equals a C8 to C12 linear or branched chain alkyl; x equals an integer of 30 to 60; y equals an integer of 5 to 35; and the average molecular weight of the copolymer is 3000.
wherein R equals a C10 to C15 linear or branched chain alkyl; y equals an integer of from 2 to 19; and M equals ammonium, calcium, magnesium, potassium, sodium and zinc; and alkylaryl polyether alcohol sulfate of the formula wherein R equals a C8 to C12 linear or branched chain alkyl; y is an integer of from 3 to 13; and M equals ammonium, calcium, magnesium, potassium, sodium and zinc; with one or more of (b) polyalkylene oxide block copolymer of the formula HOCH2CH2-O-(CH2CH2O)x-(C3H6O)y-H
where x is an integer of from 5 to 195; and y is an integer of from 5 to 150; and the average molecular weight of the copolymer is in the range of 1800 to 9000; and polyalkylene oxide block copolymer of monohydric alcohol of the formula:
18,246A-F -42-R-O-CH2CH2O-(CH2CH2O)y-(C3H6O)y-H
wherein R equals a C1 to C8 linear or branched chain alkyl; x equals an integer of from 5 to 70; y equals an integer of from 5 to 55; and the average molecular weight of the copolymer is in the range of 2400 to 3500; and polyalkylene oxide block copolymer of alkyl phenol of the formula:
wherein R equals a C8 to C12 linear or branched chain alkyl; x equals an integer of 30 to 60; y equals an integer of 5 to 35; and the average molecular weight of the copolymer is 3000.
16. Composition of Claim 15 wherein the alkyl polyether alcohol sulfate is such that R is C12 alkyl, y is an integer selected from 3 and 4 and M is sodium or ammonium; the alkylaryl polyether alcohol sulfate is such that R is C9 alkyl, y averages 3 and M is sodium or ammonium; the polyalkylene oxide block copolymer is a copolymer wherein the weight percent of the polyoxyethylene units in the molecule range from 30 to 60 percent of the average molecular weight of the polymer; the polyalkylene oxide block copolymer of monohydric alcohol is a copolymer such that R is a C4 alkyl; and the polyalkylene oxide block copolymer of alkyl phenol is a copolymer such that R is a C9 alkyl.
17. Composition of Claim 13 wherein the freezing point depressant is a lower alkylene glycol.
18,246A-F -43-
18,246A-F -43-
18. Composition of Claim 17 wherein the freezing point depressant is selected from ethylene glycol and propylene glycol.
19. Composition of Claim 1 wherein the propor-tion of 2-chloro-N-isopropylacetanilide is in the range of 40 to 60 percent; the proportion of surfactant is 2 to 6 percent and consists of anionic surfactant containing in admixture therewith up to 80 percent by weight nonionic surfactant, the surfactants being selected from those set forth in Claim 14 above; the xanthan gum is a heteropoly-saccharide having an average molecular weight in excess of one million present in a concentration in the range of 0.1 to 0.5 percent; the anticaking agent is a clay selected from Bandy Tan and Gleason clays admixed with about an equal proportion by weight of finely divided hydrated precipitated silica and the mixture of the clay and silica being from 3 to 8 percent by weight of the total composition; from 0.5 to 2 percent of sodium ligno-sulfonate; 0.1 to 0.25 percent by weight of a silicone--type antifoaming agent; and the balance substantially water; the composition having an initial viscosity at 25°C in the range of 700 to 2000 cps.
20. Composition of Claim 1 containing at least 5 pounds of 2-chloro-N-isopropylacetanilide per gallon of concentrate, at least 6 percent surfactant, an effective amount of dispersant above 1 percent, and heteropoly-saccharide gum being substantially absent.
21. Composition of Claim 1 which contains a triazine herbicide in an amount of 1 part by weight of triazine herbicide per 2 to 3 parts by weight of 2-chloro--N-isopropylacetanilide.
18,246A-F -44-
18,246A-F -44-
22. Composition of Claim 21 in which the triazine herbicide is an s-triazine compound.
23. Composition of Claim 22 wherein the s-triazine is selected from 2-chloro-4-(ethylamino)-6--(isopropylamino)-s-triazine, 2-((4-chloro-6-(ethyl-amino)-s-triazin-2-yl)amino)-2-methylpropionitrile, 2-chloro-4-(cyclopropylamino)-6-(isopropylamino)-2--triazine, 2-chloro-4,6-bis(isopropylamino)-s-triazine and 2-chloro-4,6-bis(ethylamino)-s-triazine.
24. Composition of Claim 1 which contains at least one active herbicide for broadleaf weeds which is sparingly soluble in water in an amount of 1 part by weight of herbicide per 2 to 3 parts by weight of 2-chloro-N-isopropylacetanilide.
25. Composition of Claim 24 in which at least one active herbicide is selected from sparingly soluble esters of 2,4-dichlorophenoxyacetic acid, esters of 2,5-dichloro-6-methoxy benzoic acid, methyl-5-(2,4--dichlorophenoxy)-2-nitrobenzoate, 3-(3,4-dichloro-phenyl)-1-methoxy-1-methylurea, 2-chloro-4-(ethylamino)--6-(isopropylamino)-s-triazine, 2-((4-chloro-6-(ethyl-amino)-s-triazin-2-yl)amino)-2-methylpropionitrile, 2-chloro-4-(cyclopropylamino)-6-(isopropylamino)-2-triazine, 2-chloro-4,6-bis(isopropylamino)-s-triazine, 2-chloro-4,6-bis(ethylamino)-s-triazine and 4-amino--6-tert-butyl-3-(methylthio)-as-triazin-5(4H)one.
26. Composition of Claim 1 which contains at least one active herbicide for broadleaf weeds which is freely soluble in water.
18,246A-F -45-
18,246A-F -45-
27. Composition of Claim 1 wherein the 2-chloro--N-isopropylacetanilide used is characterized as having sufficient acidic contaminants therein to produce a pH
below 4 and above 1 when formed into a 10 percent by weight suspension in water and the proportion of dis-persing agent is an effective amount greater than 6 percent by weight.
below 4 and above 1 when formed into a 10 percent by weight suspension in water and the proportion of dis-persing agent is an effective amount greater than 6 percent by weight.
28. Composition of Claim 21 in which the com-bined 2-chloro-N-isopropylacetanilide and triazine content is in the range of 40 to 60 percent by weight and the amount of dispersant is in the range of 0.5 to 4 percent by weight.
29. Composition of Claim 28 wherein the tria-zine is 2-chloro-4-(ethylamino)-6-(isopropylamino)-s--triazine, 2-chloro-4-(cyclopropylamino)-6-(isopropylamino)--2-triazine or 4-amino-6-tert-butyl-3-(methylthio)-as--triazin-5(4H)one.
30. Composition of Claim 25 wherein the com-bined content of 2-chloro-N-isopropylacetanilide and at least one other active herbicide for broadleaf weeds is in the range of 40 to 60 percent by weight and the amount of dispersant is in the range of 0.5 to 4 percent by weight.
18,246A-F -46-
18,246A-F -46-
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000347785A CA1120745A (en) | 1980-03-17 | 1980-03-17 | Flowable 2-chloro-n-isopropylacetanilide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000347785A CA1120745A (en) | 1980-03-17 | 1980-03-17 | Flowable 2-chloro-n-isopropylacetanilide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1120745A true CA1120745A (en) | 1982-03-30 |
Family
ID=4116487
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000347785A Expired CA1120745A (en) | 1980-03-17 | 1980-03-17 | Flowable 2-chloro-n-isopropylacetanilide |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1120745A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0356812A2 (en) * | 1988-08-26 | 1990-03-07 | BASF Corporation | Adjuvants for use with crop protection agents |
| EP1986494B2 (en) † | 2006-02-23 | 2023-10-18 | Fmc Corporation | Stable mixtures of microencapsulated and non-encapsulated pesticides |
-
1980
- 1980-03-17 CA CA000347785A patent/CA1120745A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0356812A2 (en) * | 1988-08-26 | 1990-03-07 | BASF Corporation | Adjuvants for use with crop protection agents |
| EP0356812A3 (en) * | 1988-08-26 | 1991-05-15 | BASF Corporation | Adjuvants for use with crop protection agents |
| AU625194B2 (en) * | 1988-08-26 | 1992-07-02 | Basf Corporation | Adjuvants for use with crop protection agents |
| EP1986494B2 (en) † | 2006-02-23 | 2023-10-18 | Fmc Corporation | Stable mixtures of microencapsulated and non-encapsulated pesticides |
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