AQUEOUS ADJUVANT CONCENTRATES WITH IMPROVED SPRAY
DRIFT PROPERTIES
TECHNICAL FIELD
[0001] The invention relates to a stable aqueous adjuvant concentrate having
improved spray drift properties comprising a hydroxypropyl tamarind gum, a
potassium salt and a surfactant.
[0002] The invention further relates to stable sprayable diluted herbicidal
formations containing said aqueous adjuvant concentrate and at least a
herbicide.
BACKGROUND OF THE ART
[0003] Many known agrochemicals have shown to be more effective in
combination than when applied individually.
[0004] Herbicides, and in particular glyphosate, are usually sprayed in
combination with organic adjuvants (such as surfactants acting as wetting
agents and stickers) and inorganic adjuvants (such as inorganic nitrogen or
potassium containing fertilizers). The presence of the various adjuvants
guarantees good phytoactivity and avoids detrimental and/or unpredictable
effects due to local conditions (water hardness, soil quality, weather
conditions, etc).
[0005] Various systems have been devised for convenient dosing of
agrochemicals, such as herbicides, on field, crop area, plants etc., for
example spray pumps which spray diluted agrochemical formulations (tank
mix) from a opportune manifold onto the area of land or crop area, or more
complex apparatus which are designed to dose concentrated agrochemical
formulations into the pump and to mix them with water before being sprayed.
[0006] During the spraying of agrochemicals, it is necessary to add anti-drift
agents (drift control agents) in order to prevent the formation of fine droplets,
which could be carried beyond the area intended to be treated. Without the
use of anti-drift agents, the spraying could be largely inefficient, first of all
because there could be an inadequate treatment of the land and crop areas
to be treated and secondly because the extraneous spray, if carried beyond
the intended treatment zone, could be detrimental to other crops, land and
water courses.
[0007] Typical drift control agents are synthetic or natural polymers such as
polyacrylamides, polyethylene oxides, polyvinyl pyrrolidones, guar gum and
guar gum derivatives. In particular in the agriculture industry, polyacrylamides
and guar gum and its derivatives are the standard additives for spray drift
control.
[0008] It is usual to combine the anti-drift agent in the agrochemical
formulations diluted for the spray application (tank-mix). Alternatively the antidrift
agent is dissolved in either the water which is fed into the spray pumps or
applied directly into the spray pumps, usually at or shortly after the mixing
zone where the water is mixed with the herbicide, pesticide or aqueous
fertilizer concentrate. It is important that the spray drift chemical is correctly
dosed and well dissolved to ensure that extraneous spray is not formed
through under dosing or through overdosing or the spray angle is too narrow
resulting in uneven distribution of the agrochemical.
[0009] However, these procedures have the problem that polymers, such as
polyacrylamides, guar and guar derivatives, can be difficult to activate in field
situations and polymer powders take a long time to dissolve. This can lead to
the formation of gel particles which can block in-line screens and nozzles,
resulting in pressure buildup in the system and spotty spray patterns.
[0010] A good solution to this problem could be dissolving/dispersing an
adequate amount of anti-drift agent directly in the agrochemical concentrates.
However, it is really difficult to dissolve sufficient polymer in the concentrates
without obtaining solution with an unacceptable or unmanageable viscosity
and/or to obtain stable solutions to achieve adequate spray drift in all cases.
Furthermore, the types of polymeric anti-drift agents will be limited to the few
which are easily soluble in the compositions to give adequate spray drift
properties.
[001 1] It is well known in the art that it is possible to prepare stable
suspensions/dispersions of polysaccharides in concentrated solutions of
electrolytes, such as ammonium or alkali salts of sulfate, nitrate and
phosphate. These suspensions/dispersions are described for example in
US 4,971 ,728, US 4,272,414 and US 6,322,726, but none of these patents
describes an adjuvant composition containing also a high amount of
surfactant(s).
[0012] Suspensions/dispersions of polysaccharides in solution of electrolytes
and surfactants are described in US 4,883,537, US 5,898,072, EP 4 13274
and US 201 1/0054042 and EP 2606724.
[0013] US 201 1/0054042, for example, describes compositions containing
ammonium sulfate at concentration around 25-30 % by weight and HPG at a
concentration around 2-6% by weight and an alkyl betaine in the presence of
a suspending agent, typically fumed silica, and/or a water soluble organic
solvents.
[0014] US 6,364,926 describes concentrated liquid adjuvant compositions
comprising, by weight of the composition: a) about 25% to about 35% of a
nitrogen compound in the form of an ammonium salt; b) about 0.1 % to about
5% of an ampholytic surfactant, c) about 0.1 % to about 2.5% of a drift control
agent/deposition aid (hydroxypropyl guar), and d) about 55% to about 75% of
a carrier. In this adjuvant concentrate both fertilizers and surfactants are
present, but the concentration of drift control agent is quite low and does not
allow high dilutions of the concentrates.
[0015] However these suspensions/dispersions are metastable systems and
require the addition of a suspending agent for stabilization.
[0016] Unfortunately suspending agents are usually thickeners, such as clays,
fumed silica or polymeric thickening agents, which further increase the
viscosity of the suspensions/dispersions, reducing on-field manageability of
the adjuvant compositions.
[0017] Alternatively, particular and time consuming methods of dissolution
were developed, as described in EP 2606724 which discloses an aqueous
adjuvant concentrate with improved spray drift properties and method for its
preparation comprising the steps of: i) dissolving from 15 to 30 % by weight,
on the weight of the final concentrate, of ammonium sulfate in water; ii)
adding to the solution from 1 to 10 % by weight, on the weight of the final
concentrate, of anionic esters of alkyl polyglycosides; iii) dispersing in the
solution from 2 to 10 % by weight, on the weight of the final concentrate, of
hydroxypropyl guar or hydroxypropyl guar acetate; iiii) adding ammonium
sulfate to the dispersion to reach an ammonium sulfate final concentration
comprised between 33 and 40% by weight.
[0018] We have now discovered that stable and low viscosity aqueous
adjuvant concentrates comprising, dissolved therein, up to 9 % by weight of a
hydroxypropyl tamarind gum (HPT) as anti-drift agents, from 15 to 45 % by
weight of potassium salts and up to 6 % by weight of surfactants can be
easily prepared, also without the use of a suspending agent or complex
method of preparation. These concentrates contain high amount of dissolved
adjuvants and anti-drift agent, are stable also in difficult environmental
conditions, and, at the same time, they are easily pourable and manageable.
For these reasons, they can be used to prepare directly in locus diluted
sprayable herbicidal formulations, in particular glyphosate based formulations,
with excellent anti-drift characteristics.
SUMMARY OF THE INVENTION
[0019] In one embodiment, the present invention is an aqueous adjuvant
concentrate comprising, dissolved therein: from 15 to 45 % by weight,
preferably from 20 to 35 % by weight, of a potassium salt chosen among dipotassium
phosphate, potassium sulfate, potassium nitrate, tri-potassium
citrate, potassium salts of ethylenediaminetetraacetic acid (EDTA) and
mixture thereof; from 0.5 to 6 % by weight, preferably 1 to 4 % by weight, of at
least a surfactant and, from 3 to 9 % by weight, preferably 4 to 8 % by weight,
of a hydroxypropyl tamarind gum (HPT).
[0020] It is a further object of the present invention a sprayable herbicidal
formulation comprising from 0.01 to 5% by weight of at least one herbicide
and said aqueous adjuvant concentrate in such an amount that the
concentration of HPT in the formulation is comprised between 0.01 and 0.4 %
by weight.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Suitable potassium salts of EDTA are the mono-potassium EDTA, dipotassium
EDTA, tri-potassium EDTA and tetra-potassium EDTA. Dipotassium
EDTA is particularly preferred.
[0022] In a preferred embodiment, said potassium salt is a mixture of dipotassium
phosphate, potassium nitrate and tri-potassium citrate.
[0023] Typically the aqueous adjuvant concentrate of the invention comprise
at least 30% by weight, preferably from 40 to 60% by weight, of water.
[0024] Anionic, cationic, non-ionic and ampholytic surfactants and mixtures
thereof can be used as the surfactant b). Suitable surfactants are, for
example, nonionic emulsifiers and dispersants, such as: polyalkoxylated,
preferably polyethoxylated, saturated and unsaturated aliphatic alcohols,
having 8 to 24 carbon atoms in the alkyl radical, which is derived from the
corresponding fatty acids or from petrochemical products, and having 1 to
100, preferably 4 to 40, ethylene oxide units (EO); polyalkoxylated, preferably
polyethoxylated, arylalkylphenols, such as, for example, tristyrylphenol having
an average degree of ethoxylation of between 8 and 80, preferably from 16 to
40; polyalkoxylated, preferably polyethoxylated, alkylphenols having one or
more alkyl radicals, such as, for example, nonylphenol or tri-sec-butylphenol,
and a degree of ethoxylation of between 2 and 40, preferably from 4 to 20;
polyalkoxylated, preferably polyethoxylated, hydroxy-fatty acids or glycerides
of hydroxy-fatty acids, such as, for example, castor oil, having a degree of
ethoxylation of between 10 and 80; sorbitan or sorbitol esters with fatty acids
or polyalkoxylated, preferably polyethoxylated, sorbitan or sorbitol esters;
polyalkoxylated, preferably polyethoxylated, amines; di- and tri-block
copolymers, for example from alkylene oxides, for example from ethylene
oxide and propylene oxide, having average molar masses between 200 and
8000 g/mol, preferably from 1000 to 4000 g/mol; alkylpolyglycosides or
polyalkoxylated, preferably polyethoxylated, alkylpolyglycosides.
[0025] Preferred nonionic surfactants are polyethoxylated alcohols, preferably
from renewable resources, such as ethoxylated (4-8 EO) C 2-C14 natural
alcohol; polyethoxylated triglycerides of hydroxy-fatty acids and polyethylene
oxide/polypropylene oxide block copolymers.
[0026] Also suitable are anionic surfactants, for example: polyalkoxylated,
preferably polyethoxylated, surfactants which are ionically modified, for
example by conversion of the terminal free hydroxyl function of the alkylene
oxide block into a sulfate or phosphate ester; alkali metal and alkaline earth
metal salts of alkylarylsulfonic acids having a straight-chain or branched alkyl
chain; alkali metal and alkaline earth metal salts of paraffin-sulfonic acids and
chlorinated paraffin-sulfonic acids; polyelectrolytes, such as lignosulfonates,
condensates of naphthalenesulfonate and formaldehyde,
polystyrenesulfonate or sulfonated unsaturated or aromatic polymers; anionic
esters of alkylpolyglycosides, such as those described in WO 201 0/1 00039,
for example alkylpolyglucoside sulfosuccinate or citrate; sulfosuccinates
which are esterified once or twice with linear, or branched aliphatic,
cycloaliphatic and/or aromatic alcohols, or sulfosuccinates which are
esterified once or twice with (poly)alkylene oxide adducts of alcohols.
[0027] Examples of cationic and ampholytic surfactants are quaternary
ammonium salts, alkyl amino acids, and betaine or imidazoline
amphotensides.
[0028] Preferably the surfactants are anionic surfactants. Preferred anionic
surfactants are, for example, salts of alkyl sulfosuccinic acids, such as sodium
dioctyl sulfosuccinate, and anionic esters of alkylpolyglycosides, in particular
alkylpolyglucoside citrate.
[0029] Tamarind (Tamahndus Indica) is a leguminous evergreen tall tree
produced in the tropics. Tamarind gum (tamarind powder or tamarind kernel
powder), a xyloglucan polysaccharide, is obtained by extracting and purifying
the seed powders, obtained by grinding the seeds of tamarind.
[0030] The polysaccharide molecule of the tamarind gum consists of a main
linear chain of poly-glucose bearing xylose and galactoxylose substituents
[0031] The procedure for the preparation of a hydroxypropyl tamarind gum is
known in the art, and usually comprises the following steps: tamarind gum is
treated with an organic-aqueous alkaline hydroxide and is reacted with
propylene oxide; the alkaline hydroxide is neutralized, the possible organic
diluent is distilled off and the product obtained is dried, ground and sieved to
obtain a hydroxypropyl tamarind gum derivative.
[0032] The hydroxypropyl tamarind gum of the invention has preferably a
molar hydroxypropyl substitution ranging from 0.1 to 2.5, preferably from 0.2
to 1.0.
[0033] The HP tamarind gum may also contain further substituent groups
such as carboxyalkyl substituents, wherein the alkyl represents hydrocarbon
moiety having 1 to 3 carbon atoms (e.g., carboxymethyl or carboxyethyl) or
hydrophobic substituents or combination thereof.
[0034] The hydrophobic modification of the HP tamarind gum of the invention
is obtained by the introduction of hydrophobic group.
[0035] Typical derivatizing agents bringing a hydrophobic group include C2-
C24 linear or branched alkyl and alkenyl halides or linear, C 6-C24 linear or
branched alkyl and alkenyl epoxides and alkyl and alkenyl glycidyl ethers
containing a C4-C24 linear or branched hydrocarbon group.
[0036] The hydrophobically modified HP tamarind gum of the invention may
have hydrophobic degree of substitution (DSH) of from 1*10 5 to 5*1 0 1 ,
preferably from 1A 0 4 to 1A 0 1 .
[0037] Preferably, the hydrophobically modified HP tamarind gum of the
invention contains as hydrophobic groups C4-C24 alkyl chains.
[0038] Preferably the hydrophobizing agent is a alkyl or alkenyl glycidylether
containing a C4-C24 linear or branched hydrocarbon group.
[0039] Halo-carboxylic acids, such as monochloroacetic acid, or their salts
can be used for the preparation of carboxyalkyi HP tamarind gum.
[0040] The carboxyalkyi HP tamarind gum may have a carboxyalkyi DS of
from 0.01 to 0.5, preferably from 0.05 to 0.3.
[0041] After the preparation, the HP tamarind gum can be treated with several
known reagents, for example: caustic; acids; biochemical oxidants, such as
galactose oxidase; chemical oxidants, such as hydrogen peroxide; and
enzymatic reagents; or by physical methods using high speed agitation
machines; thermal methods; and combinations of these reagents and
methods. Reagents such as sodium metabisulfite or inorganic salts of bisulfite
may also be optionally included.
[0042] The treatments described here above can be also performed on the
tamarind gum before the derivatization process.
[0043] In a preferred embodiment, the HP tamarind gum is a depolymerized
HP tamarind gum, which has been depolymerized by using chemicals, such
as hydrogen peroxide, or cellulase enzymes.
[0044] In a further embodiment, the HP tamarind of the invention is purified by
extraction of the impurities with an aqueous or aqueous-organic solvent
before a final drying step so as to remove the salts and by-products formed
during the reaction.
[0045] However, technical grade HP tamarind gum (i.e. not purified from the
reaction by-products) is also suitable for the scope of the invention.
[0046] Preferably, the HP tamarind gum useful for the present invention has
Brookfield® RV viscosity at 20 °C, 20 rpm and 5 % in water comprised
between 500 and 20,000 mPa s, preferably between 2,000 and 10,000
mPa s.
[0047] Other commonly used water conditioners can be present in the
composition of the invention in an amount ranging from 0.1 to 17 % wt.
[0048] Examples of water conditioners are ammonium containing compounds,
such, ammonium sulfate, ammonium nitrate, ammonium hydrogen sulfate,
ammonium chloride, ammonium carbonate, ammonium hydrogen carbonate,
ammonium phosphate, diammonium hydrogen phosphate, ammonium
dihydrogen monophosphate, ammonium sodium hydrogen phosphate,
monocarbamide dihydrogensulphate and mixtures of these.
[0049] In one embodiment of the invention, the pH of the adjuvant concentrate
is brought to value ranging from 6.5 to 8.5, preferably from 7.0 to 8.0, by
adding an appropriate amount of acid.
[0050] Carboxylic acids, both mono- and poly-carboxylic acids, are the
preferred acids. Suitable examples are, without limitation, acetic acid,
propanoic acid, butanoic acid, gluconic acid, lactic acid, oxalic acid, succinic
acid, pyruvic acid malic, acid, malonic acid, citric acid, isocitric acid and
mixtures thereof.
[0051] In a further embodiment of the invention, the aqueous adjuvant
concentrate comprises from 0.03 to 1 % by weight of a suspending agent.
Any kind of suspending agent can be used for the realization of the present
invention. Suitable suspending agents include, but are not limited to, silica,
attapulgite and bentonite clays, or their derivatives such as hydrated fumed
silica or amine treated attapulgite clays.
[0052] Optionally, the adjuvant concentrate may also include additives
commonly used in the field, such as humectants, corrosion inhibitors,
microbial inhibitors, anti-foam agents, or mixture thereof.
[0053] No special or particular equipment is required for the preparation of the
aqueous adjuvant concentrate of the invention. The inorganic salt and the
surfactant, and optionally other additives, can be dissolved in water utilizing a
common equipment. The same equipment can be used for dissolving the
tamarind gum derivatives in the obtained salt solution.
[0054] The aqueous adjuvant concentrate is stable; with the term "stable" we
mean that no phase separation or precipitation or gelification occur, also in
difficult environmental conditions, such as high (>40 °C) or low (<1 0 °C)
temperatures for at least one week from its preparation.
[0055] The stability of the suspension of this invention can be further improved
by mixing the dispersion under vacuum, so as to remove entrapped air.
[0056] Usually, the aqueous adjuvant concentrates of the invention have a
Brookfield® RV viscosity, at 5 rpm and 20 °C, comprised between 2000 and
8000 mPa s.
[0057] The aqueous adjuvant concentrates of the invention are pourable,
stable, and can be stored for a long time without settling or precipitation of
solid components from the composition, despite the large amount of inorganic
salts and surfactants that they contain; advantageously, they do not comprise
any suspending agent or water soluble organic solvent, except the
hydroxypropyl tamarind gum.
[0058] The sprayable herbicide formulations according to the invention are
diluted and are obtained by adding the adjuvant concentrates to formulated
herbicides, or vice-versa, and possibly diluting with water to the desired
concentration in order to obtain aqueous formulation which can be directly
sprayed on the fields.
[0059] Alternatively, the formulated herbicide and/or the adjuvant
concentrates may be previously diluted and then mixed.
[0060] Preferably the HP tamarind gum of the invention is present in the
diluted agrochemical spray formulation at a concentration ranging from 0.01
to 0.40 % by weight.
[0061] The term "diluted" is used herein with reference to herbicide active
content comprised between 0.001 and 20% by weight.
[0062] Said sprayable herbicide formulations comprise herbicidal active
compounds, such as Acetochlor, Acibenzolar, Acibenzolar-S-methyl,
Acifluorfen, Acifluorfen-sodiunn, Adonifen, Alachlor, Allidochlor, Alloxydinn,
Alloxydinn-sodium, Ametryn, Amicarbazone, Amidochlor, Amidosulfuron,
Aminocyclopyrachlor, Aminopyralid, Amitrole, Ammonium sulfamat,
Ancymidol, Anilofos, Asulam, Atrazine, Azafenidin, Azimsulfuron, Aziprotryn,
Beflubutamid, Benazolin, Benazolin-ethyl, Bencarbazone, Benfluralin,
Benfuresate, Bensulide, Bensulfuron, Bensulfuron-methyl, Bentazone,
Benzfendizone, Benzobicyclon, Benzofenap, Benzofluor, Benzoylprop,
Bicyclopyrone, Bifenox, Bispyribac, Bispyribac-sodium, Bromacil,
Bromobutide, Bromofenoxim, Bromoxynil, Bromuron, Buminafos, Busoxinone,
Butachlor, Butafenacil, Butamifos, Butenachlor, Butralin, Butroxydim ,
Butylate, Cafenstrole, Carbetamide, Carfentrazone, Carfentrazone-ethyl,
Chlomethoxyfen, Chloramben, Chlorazifop, Chlorazifop-butyl, Chlorbromuron,
Chlorbufam, Chlorfenac, Chlorfenac-sodium, Chlorfenprop, Chlorflurenol,
Chlorflurenol-methyl, Chloridazon, Chlorimuron, Chlorimuron-ethyl,
Chlormequat-chloride, Chlornitrofen, Chlorophthalim, Chlorthal-dimethyl,
Chlorotoluron, Chlorsulfuron, Cinidon, Cinidon-ethyl, Cinmethylin,
Cinosulfuron, Clethodinn (C1 0), Clodinafop, Clodinafop-propargyl, Clofencet,
Clomazone, Clomeprop, Cloprop, Clopyralid (C1 ) , Cloransulam, Cloransulammethyl,
Cumyluron, Cyanamide, Cyanazine, Cyclanilide, Cycloate,
Cydosulfannuron, Cydoxydim (C1 1) , Cyduron, Cyhalofop, Cyhalofop-butyl,
Cyperquat, Cyprazine, Cyprazole, 2,4-D, 2,4-DB, Dalapon, Daminozide,
Dazomet, n-Decanol, Desmedipham, Desmetryn, Detosyl-Pyrazolate (DTP),
Diallate, Dicamba, Dichlobenil, Dichlorprop, Dichlorprop-P, Didofop, Diclofopmethyl,
Didofop-P-methyl, Didosulam, Diethatyl, Diethatyl-ethyl, Difenoxuron,
Difenzoquat, Diflufenican, Diflufenzopyr, Diflufenzopyr-sodium, Dimefuron,
Dikegulac-sodium, Dimefuron, Dimepiperate, Dimethachlor (C2),
Dimethametryn, Dimethenamid, Dimethenamid-P, Dimethipin,
Dimetrasulfuron, Dinitramine, Dinoseb, Dinoterb, Diphenamid, Dipropetryn,
Diquat, Diquat-dibromide, Dithiopyr, Diuron, DNOC, Eglinazine-ethyl,
Endothal, EPTC, Esprocarb, Ethalfluralin, Ethametsulfuron, Ethametsulfuronmethyl,
Ethephon, Ethidimuron, Ethiozin, Ethofumesate, Ethoxyfen,
Ethoxyfen-ethyl, Ethoxysulfuron, Etobenzanid, F-5331 , d.h. N-[2-Chloro-4-
fluoro-5-[4-(3-fluoropropyl)-4,5-dihydro-5-oxo-1 H-tetrazol-1-yl]-phenyl]-ethan
sulfonamide, F-7967, d.h. 3-[7-Chloro-5-fluoro-2-(trifluoromethyl)-1 Hbenzimidazol-
4-yl]-1 -methyl-6- (trifluormethyl)pyrimidin-2,4(1 H,3H)-dione,
Fenoprop, Fenoxaprop, Fenoxaprop-P, Fenoxaprop-ethyl, Fenoxaprop-Pethyl
(C3), Fenoxasulfone, Fentrazamide, Fenuron, Flamprop, Flamprop-Misopropyl,
Flamprop-M-methyl, Flazasulfuron, Florasulam, Fluazifop,
Fluazifop-P, Fluazifop-butyl, Fluazifop-P-butyl, Fluazolate, Flucarbazone,
Flucarbazone-sodium, Flucetosulfuron, Fluchloralin, Flufenacet
(Thiafluamide), Flufenpyr, Flufenpyr-ethyl, Flumetralin, Flumetsulam,
Flumiclorac, Flumiclorac-pentyl, Flumioxazin, Flumipropyn, Fluometuron,
Fluorodifen, Fluoroglycofen, Fluoroglycofen-ethyl, Flupoxam, Flupropacil,
Flupropanate, Flupyrsulfuron, Flupyrsulfuron-methyl-sodium, Flurenol,
Flurenol-butyl, Fluridone, Flurochloridone, Fluroxypyr, Fluroxypyr-meptyl,
Flurprimidol, Flurtamone, Fluthiacet, Fluthiacet-methyl, Fluthiamide,
Fomesafen, Foramsulfuron, Forchlorfenuron, Fosamine, Furyloxyfen,
Glufosinate, Glufosinate ammoniunn, Glyphosate, Glyphosate-diannnnoniunn,
Glyphosate-isopropylammonium, Glyphosate-potassium, H-9201 , d.h. O-
(2,4-Dimethyl-6-nitrophenyl)-O-ethyl-isopropyl phosphoramidothioate,
Halosafen , Halosulfuron , Halosulfuron-methyl, Haloxyfop, Haloxyfop-p (C4),
Haloxyfop-ethoxyethyl, Haloxyfop-P-ethoxyethyl, Haloxyfop-methyl,
Haloxyfop-P-methyl, Hexazinone, HW-02, d.h. l -(Dimethoxyphosphoryl)-
ethyl(2,4-dichlorophenoxy)acetate, Imazamethabenz, Imazamethabenzmethyl,
Imazamox (C9), Imazamox-amnnoniunn, Imazapic, Imazapyr,
Imazapyr-isopropylammoniunn, Imazaquin, Imazaquin-ammoniunn,
Imazethapyr, Imazethapyr-ammoniunn, Imazosulfuron, Inabenfide, Indanofan,
Indaziflam, Indolacetic acid (IAA), 4-lndol-3-yl-butirric acid (IBA), lodosulfuron,
lodosulfuron-methyl-sodium, loxynil, Ipfencarbazone, Isocarbamid,
Isopropalin, Isoproturon, Isouron, Isoxaben, Isoxachlortole, Isoxaflutole,
Isoxapyrifop, KUH-043, d.h. 3-({[5-(Difluoromethyl)-1 -methyl-3-
(trifluoromethyl)-l H-pyrazol-4-yl]methyl}sulfonyl)-5,5-dimethyl-4,5-dihydro1,2-
oxazole, Karbutilate, Ketospiradox, Lactofen, Lenacil, Linuron, MCPA,
MCPB, MCPB-methyl, -ethyl and -sodium, Mecoprop, Mecoprop-sodium,
Mecoprop-butotyl, Mecoprop-P-butotyl, Mecoprop-P-dimethylammoniunn,
Mecoprop-P-2-ethylhexyl, Mecoprop-P-potassium, Mefenacet, Mefluidide,
Mepiquat-chlorid, Mesosulfuron, Mesosulfuron-methyl, Mesosulfuron-methyl-
Na, Mesotrione, Methabenzthiazuron, Metam, Metamifop, Metamitron,
Metazachlor (C5), Metazasulfuron, Methazole, Methiopyrsulfuron,
Methiozolin, Methoxyphenone, Methyldymron, 1-Methylcyclopropen,
Methylisothiocyanat, Metobenzuron, Metobromuron, Metolachlor, SMetolachlor,
Metosulam, Metoxuron, Metribuzin, Metsulfuron, Metsulfuronmethyl,
Molinate, Monalide, Monocarbamide, Monocarbamidedihydrogensulfat,
Monolinuron, Monosulfuron, Monosulfuron-ester, Monuron,
MT-128, d.h. 6-Chloro-N-[(2E)-3-chloroprop-2-en-1-yl]-5-methyl-Nphenylpyridazin-
3-amine, MT-5950, d.h. N-[3-Chloro-4-(1 -methylethyl)-
phenyl]-2-methylpentanannide, NGGC-01 1, Naproanilide, Napropamide (C6),
Naptalam, NC-31 0, d.h.4-(2,4-Dichlorobenzoyl)-1 -methyl-5-
benzyloxypyrazole, Neburon, Nicosulfuron, Nipyraclofen, Nitralin, Nitrofen,
Nitrophenolat-sodium (isomer mixture), Nitrofluorfen, Nonansaure,
Norflurazon, Orbencarb, Orthosulfamuron, Oryzalin, Oxadiargyl, Oxadiazon,
Oxasulfuron, Oxaziclomefone, Oxyfluorfen, Paclobutrazol, Paraquat,
Paraquat-dichlorid, , Pendimethalin, Pendralin, Penoxsulam, Pentanochlor,
Pentoxazone, Perfluidone, Pethoxamid, Phenisopham, Phenmedipham,
Phenmedipham-ethyl, Picloram, Picolinafen, Pinoxaden, Piperophos,
Pirifenop, Pirifenop-butyl, Pretilachlor, Primisulfuron, Primisulfuron-nnethyl,
Probenazole, Profluazol, Procyazine, Prodiamine, Prifluraline, Profoxydim,
Prohexadione, Prohexadione-calcium, Prohydrojasmone, Prometon,
Prometryn, Propachlor, Propanil , Propaquizafop, Propazine, Propham ,
Propisochlor, Propoxycarbazone, Propoxycarbazone-sodium, Propyrisulfuron,
Propyzamide, Prosulfalin, Prosulfocarb, Prosulfuron, Prynachlor, Pyraclonil,
Pyraflufen, Pyraflufen-ethyl, Pyrasulfotole, Pyrazolynate (Pyrazolate),
Pyrazosulfuron, Pyrazosulfuron-ethyl, Pyrazoxyfen, Pyribambenz,
Pyribambenz-isopropyl, Pyribambenz-propyl, Pyribenzoxim, Pyributicarb,
Pyridafol, Pyridate (C7), Pyriftalid, Pyriminobac, Pyriminobac-methyl,
Pyrimisulfan, Pyrithiobac, Pyrithiobac-sodium, Pyroxasulfone, Pyroxsulam,
Quinclorac, Quinmerac, Quinoclamine, Quizalofop, Quizalofop-ethyl,
Quizalofop-P, Quizalofop-P-ethyl, Quizalofop-P-tefuryl, Rimsulfuron,
Saflufenacil, Secbumeton, Sethoxydim, Siduron, Simazine, Simetryn , SN-
106279, d.h. Methyl-(2R) -2-({7-[2-chloro-4-(trifluoromethyl)phenoxy]-2-
naphthyljoxy) propanoate, Sulcotrione, Sulfallate (CDEC), Sulfentrazone,
Sulfonneturon, Sulfonneturon-methyl, Sulfosate (Glyphosate-trimesium),
Sulfosulfuron, SYN-523, SYP-249, d.h. 1 -Ethoxy-3-methyl-1 -oxobut-3-en-2-
yl-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate, SYP-300, d .h.1 -
[7-Fluoro-3-oxo-4-(prop-2-in-1 -yl)-3,4-dihydro-2H-1 ,4-benzoxazin-6-yl]-3-
propyl-2-thioxoimidazolidin-4,5-dione, Tebutam, Tebuthiuron, Tecnazene,
Tefuryltrione, Tembotrione, Tepraloxydim, Terbacil, Terbucarb, Terbuchlor,
Terbumeton, Terbuthylazine, Terbutryn, Thenylchlor, Thiafluamide,
Thiazafluron, Thiazopyr, Thidiazimin, Thidiazuron, Thiencarbazone,
Thiencarbazone-methyl, Thifensulfuron, Thifensulfuron-methyl, Thiobencarb,
Tiocarbazil, Topramezone, Tralkoxydim, Triallate, Triasulfuron, Triaziflam,
Triazofenamide, Tribenuron, Tribenuron-methyl, Trichloroacetic acid (TCA),
Triclopyr, Tridiphane, Trietazine, Trifloxysulfuron, Trifloxysulfuron-sodium,
Trifluralin (C8), Triflusulfuron, Triflusulfuron-methyl , Trimeturon, Trinexapac,
Trinexapac-ethyl, Tritosulfuron, Tsitodef, Uniconazole, Uniconazole-P,
Vernolate, ZJ-0862, d.h.3,4-Dichloro-N-{2-[(4,6-dimethoxypyrimidin-2-
yl)oxy]benzyl}aniline or mixture thereof.
[0063] The adjuvant concentrates of the present invention are particularly
suited for the preparation of sprayable formulations of N-(phosphonomethyl)
glycine (Glyphosate) and its salts, Dicamba and its salts and 2-4D and its
salts, and mixture thereof. Particularly preferred are formulations comprising
N-(phosphonomethyl) glycine and Dicamba, or salts thereof.
[0064] Other biologically active ingredients such as other pesticides, plant
growth regulators, algicides, fungicides, bactericides, viricides, insecticides,
acaricides and nematicides may be added as partners in the sprayable
diluted herbicide formulations.
[0065] The sprayable herbicidal formulations of the invention may additionally
comprise other conventional additives, including thickeners, flow enhancers,
wetting agents, buffers, lubricants, fillers, deposition enhancers, evaporation
retardants, frost protecting agents, insect attracting odor agents, UV
protecting agents, fragrances, anti-foam agents and the like.
[0066] Application rates will depend upon the weeds to be controlled and the
degree of control desired. In general, the herbicidal formulations of this
invention are most efficiently employed at a rate of 0.001 to 22.4 kilograms
per hectare of the active ingredients, preferably 0.01 to 16.8 kilograms per
hectare.
[0067] The sprayable diluted herbicidal formulations according to the invention
give optimum drift control and droplet deposition, and have also high storage
stability and do not tend to block the spray nozzles.
[0068] In some embodiments, the invention is an aqueous adjuvant
concentrate comprising, dissolved therein: a . from 15 to 45 % by weight of a
potassium salt chosen among di-potassium phosphate, potassium sulfate,
potassium nitrate, tri-potassium citrate, potassium salts of
ethylenediaminetetraacetic acid (EDTA) and mixture thereof; b. from 0.5 to 6
% by weight of at least a surfactant and c . from 3 to 9 % by weight of a
hydroxyl propyl tamarind gum (HPT).
[0069] In another embodiment, the aqueous adjuvant is a concentrate as
described in paragraph 0068, comprising: a . from 20 to 35 % by weight of a
potassium salt chosen among di-potassium phosphate, potassium sulfate,
potassium nitrate, tri-potassium citrate, potassium salts of EDTA and mixture
thereof; b. from 1 to 4 % by weight of at least a surfactant and c . from 3 to 8
% by weight of a HPT.
[0070] In still another embodiment, the invention is an aqueous adjuvant
concentrate as described in paragraph 0068 wherein said potassium salt is a
mixture of di-potassium phosphate, potassium nitrate and tri-potassium
citrate.
[0071] In yet another embodiment, the invention is an aqueous adjuvant
concentrate as described in paragraph 0068, wherein said surfactant is an
anionic surfactant.
[0072] In one embodiment, the aqueous adjuvant concentrate is one as
described in paragraph 0071 , wherein said anionic surfactant is chosen
among alkyl sulfosuccinic acids and anionic esters of alkylpolyglycosides.
[0073] In another embodiment, the aqueous adjuvant concentrate is one as
described in paragraph 0068, wherein the hydroxypropyl tamarind gum has a
hydroxypropyl molar substitution of from 0.1 to 2.5.
[0074] In still another embodiment, the aqueous adjuvant concentrate is one
as described in paragraph 0074, wherein said hydroxypropyl tamarind gum
has a hydroxypropyl molar substitution of from 0.2 to 1.0.
[0075] In one embodiment, the invention is a sprayable herbicidal formulation
comprising from 0.01 to 5% by weight of at least one herbicide and the
aqueous adjuvant concentrate of claim 1) in such an amount that the
concentration of HPT in the formulation is comprised between 0.01 and 0.4 %
by weight.
[0076] In yet another embodiment, the sprayable herbicidal formulation as
described in paragraph 0075, is one wherein said herbicide is chosen among
N-(phosphonomethyl) glycine (Glyphosate) and its salts, Dicamba and its
salts, 2-4D and its salts, and mixture thereof.
[0077] In still another embodiment, the sprayable herbicidal formulation as
described in paragraph 0076, is one wherein said herbicide is a mixture of N-
(phosphonomethyl) glycine and Dicamba, or salts thereof.
[0078] The following Examples serve to illustrate the stability of aqueous
adjuvant concentrate according to the invention.
EXAMPLES
Example 1-16
[0079] Different amounts of potassium salts (see Tables 1-3) were dissolved
in deionized water at room temperature under stirring.
[0080] After complete solubilization, SAG® 1572, an antifoaming agent
available from Momentive Inc., and Emulson AGE/EC/UP, an alkyl
polyglucoside citrate, both commercialized by Lamberti S.p.A., were added.
[0081] The mixture was maintained under mechanical stirring until complete
dissolution, then hydroxypropyl tamarind gum was added. Two hydroxypropyl
tamarind gums were tested: HPT1 , MS 0.58 and Brookfield® RV viscosity of
2,400 mPa s at 5% wt water sol., 20 °C and 20 rpm, and HPT2, MS 0.42 and
Brookfield® RVviscosity of 6,840 mPa s at 5 % wt water sol., 20 °C and 20
rpm.
[0082] Comparative Examples were prepared by substituting the HPT with
two hydroxypropyl guar: HPG1 , having a MS of 0.25 and a Brookfield® RV
viscosity of 60,600 mPa s at 10 % wt water sol., 20°C and 20 rpm and HPG2,
having a MS of 0.29 and a Brookfield® RV viscosity of 22,700 mPa*s at 2 %
wt water sol., 20°C and 20 rpm.
[0083] The pH of some of the solutions was corrected to about 7.5 by adding
a 50% wt solution of citric acid.
[0084] A 10 % wt of Attagel 50, Attapulgite available from BASF AG, was
added to the adjuvant concentrates of Examples 14-1 6 . The 10 % wt stock
solution was prepared by pre-dispersing 10 g of Attagel 50 in 30 g of
propylene glycol, adding 60 g of water and stirring with a mechanical blade
stirrer set at about 3000 rpm. The stirring was continued until the viscosity
reached a steady state indicating full activation of the attapulgite.
[0085] Tables 1-3 show the amount in grams of the ingredients utilized and
the appearance, the cold stability (0 °C for 7 days) and the Brookfield® RV
viscosity in mPa*s, determined at 25 °C and 20 rpm, of the final solutions.
[0086] Tables 1-3 also reports the appearance of the aqueous adjuvant
concentrate after a cycle of freeze & thaw, which was conducted running 3
different cycles of freeze at 0°C for 24 hours, followed by thaw at 54°C for
other 24 hours.
Table 1
Comparative
N.D.= not deternnined
Phase Separ.= phase separation occurred
Table 2
Comparative
N.D. = not determined
Phase Separ.= phase separation occurred
Table 3
Comparative
N.D. = not determined
Phase Separ.= phase separation occurred
The aqueous adjuvant concentrates (dispersions) are considered stable when
no phase separation or precipitation or gelification occur.
Spray Drift Test
[0087] The antidrift properties of the aqueous adjuvants of the invention were
evaluated by deternnining the droplet sizes of the sprays of diluted herbicide
fornnulations prepared with the concentrates of the Examples described
above.
[0088] A Sympatec Helos/Vario KR particle size analyzer was used. This
system uses laser diffraction to determine particle size distribution in a range
from 18 to 3500 microns. All testing was performed in a low speed wind
tunnel at 15 mph. Table 4 summarize the testing parameters.
Table 4
[0089] The width of the nozzle plume was analyzed by moving the nozzle
across the laser by means of a linear actuator. The tests were replicated at
least three times for each diluted sprayable herbicide formulation.
[0090] Sprayable herbicide formulations were prepared using Roundup
PowerMax® (glyphosate based herbicide, available from Monsanto) at a
concentration of 2 % v/v in water and adding the amount of aqueous adjuvant
concentrates reported in Table 5. Water and a formulation containing only the
herbicide were used as reference. The results are reported in Table 5 .
[0091] The percent less than 150 (Pet <150 ) is the percentage of the
spray volume that is 150 and smaller, with percent less 2 10 (Pet <210
) , and 730 (Pet <730 ) being similar measurements.
Table 5
Pet
% v/v
<150 <210 <730 
-
Water 3,02 7,78 90,95
Roundup Power -
6,57 14,3 92,2
Max
Example 1 4,35 10,22 88,23
Example 3 4,61 10,71 88,83
Example 5 4,32 10,01 89,24
Example 9 4,67 10,55 89,78
Example 12 4,4 10,38 89,33
1.5
Example 14 4,26 9,88 88,1 2
0.6
Example 15 3,2 8,65 89,06
[0092] The addition of the aqueous adjuvant concentrates of the invention
result in coarser spray with a lower percentage of small droplets i.e. those
having a diameter below 150 microns, which are more prone to drift. At the
same time it produces a lower percentage of very large droplets, i.e. those
having a diameter above 730 microns, which show a lower herbicidal efficacy.
This test demonstrates the optimal spray drift properties of the aqueous
adjuvant concentrates of the invention.
CLAIMS
1. An aqueous adjuvant concentrate comprising:
a . from about 15 to about 45 % by weight of a potassium salt
chosen among di-potassium phosphate, potassium sulfate,
potassium nitrate, tri-potassium citrate, potassium salts of
ethylenediaminetetraacetic acid and mixture thereof;
b. from about 0.5 to about 6 % by weight of at least one surfactant
and
c . from about 3 to about 9 % by weight of a hydroxypropyl tamarind
gum ;
wherein a, b, and c are dissolved into the aqueous adjuvant.
2 . The aqueous adjuvant concentrate of claim 1 wherein:
a . is from about 20 to about 35 % by weight of a potassium salt
chosen among di-potassium phosphate, potassium sulfate,
potassium nitrate, tri-potassium citrate, potassium salts of
ethylenediaminetetraacetic acid, and mixture thereof;
b. from about 1 to about 4 % by weight of at least a surfactant and
c . from about 3 to about 8 % by weight of a tamarind gum.
3 . The aqueous adjuvant concentrate of claim 1 wherein the potassium
salt is a mixture of di-potassium phosphate, potassium nitrate and tripotassium
citrate.
4 . The aqueous adjuvant concentrate of claim 1 wherein the surfactant is
an anionic surfactant.
5 . The aqueous adjuvant concentrate of claim 4 wherein the anionic
surfactant is chosen among alkyl sulfosuccinic acids and anionic esters of
alkylpolyglycosides.
6 . The aqueous adjuvant concentrate of claim 1 wherein the
hydroxypropyl tamarind gum has a hydroxypropyl molar substitution of from
about 0.1 to about 2.5.
7 . The aqueous adjuvant concentrate of claim 6 wherein the
hydroxypropyl tamarind gum has a hydroxypropyl molar substitution of from
about 0.2 to about 1.0.
8 . A sprayable herbicidal formulation comprising from about 0.01 to about
5% by weight of at least one herbicide and the aqueous adjuvant concentrate
of claim 1 present in an amount such that the concentration of hydroxypropyl
tamarind gum in the formulation is from about 0.01 to about 0.4 % by weight.
9 . The sprayable herbicidal formulation of claim 8 wherein the herbicide is
chosen from the group consisting of N-(phosphonomethyl) glycine
(Glyphosate) and its salts, Dicamba and its salts, 2-4 D and its salts, and
combinations thereof.
10 . The sprayable herbicidal formulation of claim 9 wherein the herbicide is
a mixture of N-(phosphonomethyl) glycine and Dicamba.
11. The sprayable herbicidal formulation of claim 9 wherein the herbicide is
a mixture of salts of N-(phosphonomethyl) glycine and Dicamba in.