U.S. patent application number 16/922121 was filed with the patent office on 2020-11-12 for aqueous concentrated herbicidal compositions containing glyphosate salts and dicamba salts.
This patent application is currently assigned to Monsanto Technology LLC. The applicant listed for this patent is Monsanto Technology LLC. Invention is credited to Alison MacInnes.
Application Number | 20200352171 16/922121 |
Document ID | / |
Family ID | 1000004942621 |
Filed Date | 2020-11-12 |
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United States Patent
Application |
20200352171 |
Kind Code |
A1 |
MacInnes; Alison |
November 12, 2020 |
AQUEOUS CONCENTRATED HERBICIDAL COMPOSITIONS CONTAINING GLYPHOSATE
SALTS AND DICAMBA SALTS
Abstract
Herbicidal concentrate compositions containing a combination of
glyphosate salt and dicamba salt are provided. For example, a low
volatility aqueous herbicidal concentrate composition including a
glyphosate salt, dicamba salt, and a surfactant is described,
wherein (i) the composition contain a total active herbicide
loading of glyphosate salt and dicamba salt of at least about 450
grams acid equivalent per liter; (ii) the pH of the concentrate
composition is less than about 5.7; and (iii) the acid equivalent
weight ratio of glyphosate salt to dicamba salt is from about 1:1
to about 3:1.
Inventors: |
MacInnes; Alison; (St.
Louis, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Monsanto Technology LLC |
St. Louis |
MO |
US |
|
|
Assignee: |
Monsanto Technology LLC
St. Louis
MO
|
Family ID: |
1000004942621 |
Appl. No.: |
16/922121 |
Filed: |
July 7, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14405036 |
Dec 2, 2014 |
10736322 |
|
|
PCT/US2013/043995 |
Jun 4, 2013 |
|
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16922121 |
|
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|
61655018 |
Jun 4, 2012 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A01N 37/10 20130101;
A01N 57/20 20130101; A01N 37/40 20130101 |
International
Class: |
A01N 57/20 20060101
A01N057/20; A01N 37/40 20060101 A01N037/40; A01N 37/10 20060101
A01N037/10 |
Claims
1. An aqueous herbicidal concentrate composition comprising: (a) a
glyphosate component comprising the monoethanolamine salt of
glyphosate; (b) a dicamba component comprising the diglycolamine
salt of dicamba; and (c) a quaternary ammonium salt surfactant,
wherein (i) the composition contains a total active herbicide
loading of glyphosate monoethanolamine salt and dicamba
diglycolamine salt of at least about 360 grams acid equivalent per
liter; (ii) the pH of the concentrate composition is from 4.5 to
5.7; and (iii) the acid equivalent weight ratio of glyphosate
monoethanolamine salt to dicamba diglycolamine salt is from about
1:1 to about 3:1.
2. The composition of claim 1 wherein the quaternary ammonium salt
surfactant comprises a dialkoxylated quaternary ammonium salt
surfactant.
3. The composition of claim 1 wherein the quaternary ammonium salt
surfactant has a structure of formula (I): ##STR00007## wherein
R.sup.11 is hydrocarbyl or substituted hydrocarbyl having from 1 to
about 30 carbon atoms; R.sup.12 in each of the (R.sup.12O).sub.x
and (R.sup.12O).sub.y groups is independently C.sub.2-C.sub.4
alkylene; R.sup.13 is hydrogen, or a linear or branched alkyl group
having from 1 to about 4 carbon atoms; R.sup.14 is hydrocarbyl or
substituted hydrocarbyl having from 1 to about 30 carbon atoms; x
and y are from 1 to about 40; and X.sup.- is an agriculturally
acceptable anion.
4. The composition of claim 3 wherein the R.sup.11 and R.sup.14
hydrocarbyl groups are independently selected from linear or
branched alkyl having from 1 to about 25 carbon atoms, linear or
branched alkenyl having from 1 to about 25 carbon atoms, linear or
branched alkynyl having from 1 to about 25 carbon atoms, aryl, and
aralkyl groups.
5. The composition of claim 3 wherein R.sup.13 is hydrogen, methyl
or ethyl; and the sum of x and y is a number from about 2 to about
30.
6. The composition of claim 3 wherein R.sup.11 is a linear or
branched alkyl group having from about 8 to about 22 carbon atoms;
R.sup.14 is a linear or branched alkyl group having from 1 to about
22 carbon atoms; R.sup.12 in each of the (R.sup.12O).sub.x and
(R.sup.12O).sub.y groups is independently ethylene or propylene;
R.sup.13 is hydrogen or methyl; and x is a number from about 2 to
about 20.
7. The composition of claim 3 wherein R.sup.11 is a linear or
branched alkyl group having from about 8 to about 22 carbon atoms;
R.sup.14 is a linear or branched alkyl group having from 1 to about
6 carbon atoms; R.sup.12 in each of the (R.sup.12O).sub.x and
(R.sup.12O).sub.y groups is independently ethylene or propylene;
R.sup.13 is hydrogen or methyl; and x is a number from about 2 to
about 15.
8. The composition of claim 3 wherein R.sup.11 and R.sup.14 are
independently a linear or branched alkyl group having from about 8
to about 22 carbon atoms; R.sup.12 in each of the (R.sup.12O).sub.x
and (R.sup.12O).sub.y groups is independently ethylene or
propylene; R.sup.13 is hydrogen or methyl; and x is a number from
about 5 to about 15.
9. The composition of claim 1 wherein the quaternary ammonium salt
surfactant comprises a cocoalkylmethylbis(2-hydroxyethyl) ammonium
chloride salt.
10. The composition of claim 1 wherein the concentrate composition
further comprises diethylene glycol or polyethylene glycol.
11. The composition of claim 1 wherein the composition further
comprises an alkylpolysaccharide surfactant.
12. The composition of claim 11 wherein the alkylpolysaccharide
surfactant has a structure of formula (III): R.sup.5--O-(sug).sub.u
(III) wherein R.sup.5 is a straight or branched chain substituted
or unsubstituted hydrocarbyl selected from alkyl, alkenyl,
alkylphenyl, alkenylphenyl having from about 4 to about 22 carbon
atoms; the sug moiety is a saccharide residue; and u is a number
from 1 to about 10.
13. The composition of claim 12 wherein the alkylpolysaccharide
surfactant is an alkylpolyglucoside wherein R.sup.5 is a branched
or straight chain alkyl group having from 4 to 22 carbon atoms or a
mixture of alkyl groups having an average value within the given
range; sug is a glucose residue; and u is from 1 to about 5.
14. The composition of claim 1 wherein the composition has a total
surfactant concentration of from about 2.5 wt. % to about 15 wt.
%.
15. The composition of claim 1 wherein the total active herbicide
loading of glyphosate monoethanolamine salt and dicamba
diglycolamine salt is at least about 450 grams acid equivalent per
liter.
16. The composition of claim 1 wherein the total active herbicide
loading of glyphosate monoethanolamine salt and dicamba
diglycolamine salt is from about 360 g/l to about 550 g/l on an
acid equivalent basis.
17. The composition of claim 1 wherein the total active herbicide
loading of glyphosate monoethanolamine salt and dicamba
diglycolamine salt is from about 480 g/l to about 540 g/l on an
acid equivalent basis.
18. The composition of claim 1 wherein the total active herbicide
loading of glyphosate monoethanolamine salt and dicamba
diglycolamine salt is from about 480 g/l to about 520 g/l on an
acid equivalent basis.
19. The composition of claim 1 wherein the composition does not
include a polybasic polymer.
20. The composition of claim 1 wherein the pH of the concentrate
composition is from about 4.7 to 5.5.
21. The composition of claim 1 wherein the pH of the concentrate
composition is from about 5 to 5.5.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/405,036, filed Dec. 2, 2014, which is the 371 National Stage
of International PCT Application No. PCT/US2013/043995, filed Jun.
4, 2013, which claims the benefit of U.S. Provisional Application
Nos. 61/655,018, filed Jun. 4, 2012, the contents of which are
incorporated herein in their entirety.
FIELD OF THE INVENTION
[0002] The present invention generally relates to herbicidal
concentrate compositions containing a combination of herbicides. In
particular, the present invention relates to aqueous herbicidal
concentrate compositions containing glyphosate salt and dicamba
salt herbicides.
BACKGROUND OF THE INVENTION
[0003] The present invention relates generally to herbicidal
concentrate compositions, processes for preparing these
concentrates, and methods of using such compositions to kill or
control the growth and proliferation of unwanted plants. In
particular, the present invention relates to herbicidal concentrate
compositions which comprise a salt of N-(phosphonomethyl)glycine
(glyphosate) and a salt of 3,6-dichloro-2-methoxy benzoic acid
(also known as 3,6-dichloro-o-anisic acid and commonly referred to
as dicamba).
[0004] Glyphosate is well known in the art as an effective
post-emergent foliar-applied herbicide. In its acid form,
glyphosate has the following structure:
##STR00001##
[0005] Glyphosate acid is relatively insoluble in water (1.16 wt. %
at 25.degree. C.). For this reason it is typically formulated as a
water-soluble salt. For example, herbicidal concentrate
compositions and application formulations containing the sodium,
potassium, ammonium, isopropylamine, or monoethanolamine salts of
glyphosate are well known in the art.
[0006] Herbicidal compositions and formulations comprising
glyphosate or salts thereof are useful for suppressing the growth
of, or killing, unwanted plants such as grasses, weeds and the
like. Glyphosate is typically applied to the foliage of the target
plant. After application, glyphosate is absorbed by the foliar
tissue of the plant and translocated throughout the plant.
Glyphosate noncompetitively blocks an important biochemical pathway
which is common to virtually all plants, but which is absent in
animals. Although glyphosate is very effective in killing or
controlling the growth of unwanted plants, the uptake (i.e.,
absorption) of glyphosate by the plant foliar tissue and
translocation of glyphosate throughout the plant is relatively
slow. Visual symptoms that a plant has been treated with glyphosate
may not appear until one week or more after treatment.
[0007] Dicamba has proven to be a particularly effective auxin
herbicide. In its acid form, dicamba has the following
structure:
##STR00002##
[0008] Like glyphosate, dicamba is typically formulated as a salt,
such as a sodium, potassium, diethanolamine, isopropylamine,
diglycolamine, or dimethylamine salt.
[0009] Generally, auxin herbicides such as dicamba mimic or act
like natural auxin plant growth regulators. Auxin-like herbicides
appear to affect cell wall plasticity and nucleic acid metabolism,
which can lead to uncontrolled cell division and growth. The injury
symptoms caused by auxin-like herbicides include epinastic bending
and twisting of stems and petioles, leaf cupping and curling, and
abnormal leaf shape and venation.
[0010] Off-site movement is commonly associated with dicamba and
other auxin herbicides. Under certain conditions of application,
dicamba can migrate from the application site to adjacent crop
plants, such as soybeans and cotton, where contact damage to
sensitive plants can occur. Various strategies have been suggested
to reduce off-site movement of dicamba including formulating
dicamba in the form of certain mineral or amine salts,
encapsulating dicamba with a polymeric coating, and complexing with
a polybasic polymer.
[0011] With the development of transgenic plants including stacked
glyphosate-tolerant and dicamba-tolerant traits, herbicidal
compositions containing a combination of glyphosate and dicamba are
particularly beneficial and convenient for control of unwanted
plants. There is a need for highly concentrated herbicidal
compositions containing glyphosate and dicamba that can be
economically produced while having sufficient stability and that
can be diluted to provide effective spray formulation solutions for
application to unwanted plants.
[0012] As will be clear from the disclosure that follows, these and
other benefits are provided by the present invention.
SUMMARY OF THE INVENTION
[0013] In general, the present invention is directed to herbicidal
concentrate compositions containing a combination of glyphosate
salt and dicamba salt. In various embodiments, the concentrate
compositions are low volatility aqueous herbicidal concentrate
compositions including a glyphosate component comprising a
glyphosate salt (e.g., monoethanolamine salt of glyphosate), a
dicamba component comprising a dicamba salt (e.g., diglycolamine
salt of dicamba), and a surfactant. In these embodiments, (i) the
compositions contain a total active herbicide loading of glyphosate
salt and dicamba salt of at least about 450 grams acid equivalent
per liter; (ii) the pH of the concentrate composition is less than
about 5.7; and (iii) the acid equivalent weight ratio of glyphosate
salt to dicamba salt is from about 1:1 to about 3:1.
[0014] Other objects and features will be in part apparent and in
part pointed out hereinafter.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The present invention is directed to aqueous herbicidal
concentrate compositions comprising glyphosate salt and dicamba
salt herbicides.
[0016] One aspect of the present invention is to provide a highly
concentrated herbicidal composition containing glyphosate salt and
dicamba salt that can be diluted to provide an effective spray
formulation solution. A highly concentrated composition reduces the
volume of the liquid and associated packaging that would otherwise
be required for more dilute compositions. The smaller volume
reduces space required to store and transport the concentrate
composition prior to sale or use. Further, a highly concentrated
herbicidal composition containing both glyphosate salt and dicamba
salt is convenient for agricultural workers that formulate spray
solutions and avoids the risk of tank mixing errors.
[0017] Another aspect of the present invention is to provide a
stable and compatible highly concentrated herbicidal composition
containing both glyphosate salt and dicamba salt that is relatively
clear and does not appreciably separate into phases or form
precipitates upon standing or storage. A stable and compatible
highly concentrated herbicidal composition beneficially provides a
uniform spray formulation solution upon dilution without the need
for excessive agitation.
[0018] Another aspect of the present invention is to provide a
highly concentrated herbicidal composition containing glyphosate
salt, dicamba salt, and at least one surfactant. Incorporation of
at least one surfactant beneficially increases the effectiveness of
the glyphosate and dicamba active ingredients upon application to
the foliar tissues of undesired plants.
[0019] Yet another aspect of the present invention is to provide a
highly concentrated herbicidal composition containing glyphosate
salt and dicamba salt that is economical to produce.
[0020] In accordance with the present invention, the aqueous
herbicidal concentrate composition comprises a glyphosate component
comprising one or more water-soluble salts of glyphosate.
Glyphosate salts known in the art include mono, di- or tribasic and
include ammonium (e.g., mono-, di- or triammonium), alkali metal
(e.g., potassium or sodium), sulfonium (e.g., mono-, di- or
trimethylsulfonium) and organic ammonium salts of
N-(phosphonomethyl)glycine. The organic ammonium salts, commonly
referred to as amine salts, can comprise aliphatic or aromatic
amine salts and can include primary, secondary, tertiary or
quaternary amine salts. Representative examples of such organic
amine salts include isopropylamine, n-propylamine, ethylamine,
dimethylamine, monoethanolamine, ethylenediamine and
hexamethylenediamine salts of N-(phosphonomethyl)glycine. The
monoethanolamine salt and potassium salt of glyphosate have been
found to be particularly suitable for achieving high herbicidal
loadings in the concentrate compositions of the present invention
that further include a dicamba salt. Therefore, in various
embodiments, the glyphosate component of the aqueous herbicidal
concentrate composition of the present invention comprises a
glyphosate salt selected from the group consisting of the
monoethanolamine salt, potassium salt, and mixtures thereof. In
certain embodiments, the aqueous herbicidal concentrate contains
glyphosate in the form of the monoethanolamine salt. In other
embodiments, the aqueous herbicidal concentrate composition
contains glyphosate in the form of the potassium salt. In some
embodiments, the aqueous herbicidal concentrate composition
contains glyphosate in the form of the isopropylamine salt.
[0021] In accordance with the present invention, the aqueous
herbicidal concentrate composition further comprises a dicamba
component comprising one or more salts of dicamba. Dicamba salts
known in the art include, for example, the sodium, potassium,
monoethanolamine, diethanolamine, isopropylamine, diglycolamine and
dimethylamine salts. Accordingly, in various embodiments, the
dicamba component of the aqueous herbicidal concentrate composition
comprises a dicamba salt selected from the group consisting of the
sodium, potassium, monoethanolamine, diethanolamine,
isopropylamine, diglycolamine and dimethylamine salts. In these and
other embodiments, the aqueous herbicidal concentrate composition
comprises a dicamba salt selected from the group consisting of the
monoethanolamine salt, diglycolamine salt, potassium salt, and
mixtures thereof. In certain embodiments, the aqueous herbicidal
concentrate composition contains the monoethanolamine salt of
dicamba. In other embodiments, the aqueous herbicidal concentrate
composition contains the diglycolamine salt of dicamba.
[0022] Other salts of dicamba for use in the practice of the
present invention include polyamine salts such as those described
in International Patent Application Publication WO 2011/039172,
which is incorporated herein by reference for all relevant
purposes. The salts described in WO 2011/03917 include an anionic
pesticide, such as dicamba, and a cationic polyamine of formula
(A)
##STR00003##
[0023] wherein R.sup.1, R.sup.2, R.sup.4, R.sup.6 and R.sup.7 are
independently H or C.sub.1-C.sub.6-alkyl, which is optionally
substituted with OH, R.sup.3 and R.sup.5 are independently
C.sub.2-C.sub.4-alkylene, X is OH or NR.sup.6R.sup.7, and n is from
1 to 20; or a cationic polyamine of formula (B)
##STR00004##
[0024] wherein R.sup.10 and R.sup.11 are independently H or
C.sub.1-C.sub.6-alkyl, R.sup.12 is C.sub.1-C.sub.12-alkylene, and
R.sup.13 is an aliphatic C.sub.5-C.sub.8 ring system, which
comprises either nitrogen in the ring or which is substituted with
at least one unit NR.sup.10R.sup.11. Examples of these cationic
polyamines include tetraethylenepentamine, triethylenetetramine,
diethylenetriamine, pentamethyldiethylenetriamine,
N,N,N',N'',N''-pentamethyl-dipropylenetriamine,
N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine,
N'-(3-(dimethylamino)propyl)-N,N-dimethyl-1,3-propanediamine,
N,N-bis(3-aminopropyl) methylamine,
N-(3-dimethylaminopropyl)-N,N-diisopropanolamine,
N,N,N'-trimethylaminoethyl-ethanolamine,
aminopropylmonomethylethanolamine, and aminoethylethanolamine.
Accordingly, in various embodiments, the aqueous herbicidal
concentrate composition comprises a dicamba salt comprising a
cationic polyamine of formula A or B above.
[0025] The aqueous herbicidal concentrate composition may contain
various combinations of glyphosate and dicamba salts. However, in
accordance with some embodiments, certain combinations of
glyphosate and dicamba salts are selected in order to achieve
highly concentrated and stable herbicidal compositions and provide
other advantages as described herein. In various embodiments, the
aqueous herbicidal concentrate composition comprises glyphosate in
the form of the monoethanolamine salt and a dicamba salt selected
from the group consisting of the diglycolamine salt,
monoethanolamine salt, potassium salt and mixtures thereof. In
these and other embodiments, the aqueous herbicidal concentrate
composition comprises the monoethanolamine salt of glyphosate and
the diglycolamine salt of dicamba. In still other embodiments, the
aqueous herbicidal concentrate composition contains glyphosate in
the form of the potassium salt and a dicamba salt selected from the
group consisting of the diglycolamine salt, monoethanolamine salt,
potassium salt and mixtures thereof. In certain embodiments, the
counter-ion of the glyphosate salt component and the dicamba salt
component of the herbicidal concentrate composition are the same.
For example, the herbicidal concentrate composition can include
glyphosate and dicamba both in the form of the monoethanolamine or
potassium salt of the herbicidal active ingredients.
[0026] Generally, the aqueous herbicidal concentrate compositions
of the present invention include glyphosate and dicamba in
relatively equal proportions or an excess of glyphosate on an acid
equivalent (a.e.) basis. As used herein, the term "acid equivalent"
or "a.e." refers to the amount of herbicide present without taking
into account the weight of the counter-ion of the salt species
present. In various embodiments, the acid equivalent weight ratio
of glyphosate salt to dicamba salt ranges from about 1:1 to about
5:1, from about 1:1 to about 3:1, from about 1.5:1 to about 3:1,
from about 1.5:1 to about 2.5:1, or from about 1.5:1 to about 2:1.
In certain embodiments, the acid equivalent weight ratio of
glyphosate salt to dicamba salt is about 1.5:1, about 2:1, or about
3:1. It has been discovered that the ability to incorporate a
surfactant into a stable glyphosate and dicamba herbicidal
concentrate (i.e., without precipitation or phase separation) is
influenced by the ratio of glyphosate to dicamba present in the
herbicidal concentrate composition. More particularly, surfactant
compatibility in the herbicidal concentrate composition improves as
the acid equivalent weight ratio of glyphosate salt to dicamba salt
decreases.
[0027] Within these relative proportions of glyphosate and dicamba
salts, the aqueous herbicidal concentrate compositions of the
present invention provide a high total active herbicide loading of
glyphosate salt and dicamba salt. Typically, the total active
herbicide loading of glyphosate salt and dicamba salt is at least
about 360 g/l, at least about 380 g/l, at least about 400 g/l, at
least about 410 g/l, at least about 420 g/l, at least about 430
g/l, at least about 440 g/l, at least about 450 g/l, at least about
460 g/l, at least about 470 g/l, at least about 480 g/l, at least
about 490 g/l, at least about 500 g/l, at least about 510 g/l, at
least about 520 g/l, or at least about 530 g/l on an acid
equivalent basis. In various embodiments, the total active
herbicide loading of glyphosate salt and dicamba salt is from about
360 g/l to about 550 g/l, from about 380 g/l to about 540 g/l, from
about 400 g/l to about 540 g/l, from about 410 g/l to about 540
g/l, from about 420 g/l to about 540 g/l, from about 430 g/l to
about 540 g/l, from about from about 440 g/l to about 540 g/l, from
about 450 g/l to about 540 g/l, from about 460 g/l to about 540
g/l, from about 470 g/l to about 540 g/l, from about 480 g/l to
about 540 g/l, from about 480 g/l to about 530 g/l, or from about
480 g/l to about 520 g/l on an acid equivalent basis. In these and
other embodiments, the aqueous herbicidal concentrate compositions
contain a total active herbicide loading of glyphosate salt and
dicamba salt of about 480 g/l, about 500 g/l, about 520 g/l, or
about 530 g/l on an acid equivalent basis.
[0028] The pH of the aqueous herbicidal concentrate composition is
an important aspect of the present invention. The pH of the
herbicidal concentrate composition has an effect on the
compatibility between glyphosate and dicamba herbicide salt
components and the total herbicide loading that can be achieved,
the ability to incorporate a surfactant into a stable concentrate
composition as well as the volatility of the dicamba component of
the composition. Increasing the pH of the concentrate composition
often allows a higher concentration of surfactant to be
incorporated and also generally reduces volatility of the dicamba
herbicide component. However, increasing the pH requires greater
expenditure of base used to neutralize the herbicidal active
ingredients. Moreover, the effect of pH on compatibility between
the glyphosate and dicamba salts and total herbicide loading is
dependent upon the particular salt of glyphosate employed and is
not always consistent over the entire pH range. For example, it has
been discovered that the monoethanolamine salt of glyphosate
exhibits a high degree of compatibility with dicamba salts.
However, the compatibility of the isopropylamine salt of glyphosate
with dicamba salts and the total herbicide loading that can be
achieved tends to decrease as the pH increases, while the
compatibility of the potassium salt of glyphosate with dicamba
salts generally increases as the pH increases, at least over some
interval of the pH range typically employed.
[0029] Despite these various and sometimes countervailing
considerations with respect to pH, it has been discovered that a
stable, compatible herbicidal concentrate of glyphosate and dicamba
salts can be advantageously prepared at a relatively acidic pH
thereby minimizing the cost associated with neutralization of the
herbicidal active ingredients, while nevertheless maintaining
dicamba volatility at acceptable levels and permitting the
formulation of herbicidal concentrate compositions containing
appreciable concentrations of useful surfactants.
[0030] Typically, the pH of the concentrate compositions is less
than about 5.7, less than about 5.6, less than about 5.5, less than
about 5.4, less than about 5.3, less than about 5.2, less than
about 5.1, less than about 5, less than about 4.9, or less than
about 4.8. In various embodiments, the pH of the concentrate
compositions is from about 4.5 to about 5.7, from about 4.8 to
about 5.7, from about 5 to about 5.7, from about 4.5 to about 5.6,
from about 4.8 to about 5.6, from about 5 to 5.6, from about 4.5 to
about 5.5, from about 4.8 to about 5.5, from about 5 to 5.5, from
about 4.5 to about 5.4, from about 4.8 to about 5.4, or from about
5 to about 5.4. The pH of the herbicidal concentrate compositions
is measured using conventional pH measuring equipment (e.g., by
immersing the probe of a pH meter into the concentrate). A suitable
pH measurement protocol is described in Example 6.
[0031] The aqueous herbicidal concentrate compositions of the
present invention typically include a surfactant to enhance the
herbicidal effectiveness of the glyphosate and dicamba salts in
spray formulations prepared by dilution of the concentrate for
application to unwanted plants. As noted above, it is believed the
ratio of glyphosate to dicamba affects the degree to which one or
more surfactants may be incorporated into the aqueous herbicidal
concentrate composition. When dicamba salt is present in higher
concentrations (e.g., from about 1:1 to about 3:1 glyphosate to
dicamba acid equivalent weight ratio), it has been observed that a
wider range of surfactants can be incorporated into the aqueous
herbicidal concentrate composition without precipitation or phase
separation as compared to compositions having a lower concentration
of dicamba salt (e.g., 5:1 glyphosate to dicamba acid equivalent
weight ratio). Accordingly, in certain embodiments, the acid
equivalent weight ratio of glyphosate salt to dicamba salt is from
about 1:1 to about 3:1, from about 1.5:1 to about 3:1, from about
1.5:1 to about 2.5:1, from about 1:1 to about 2:1, from about 1.5:1
to about 2:1, or from about 1.7:1 to about 2:1.
[0032] It has been discovered that some surfactants conventionally
used in the art in combination with glyphosate and/or dicamba
herbicides are difficult to successfully incorporate into a stable
concentrate composition, even at lower acid equivalent weight
ratios of glyphosate salt to dicamba salt. Nevertheless, applicants
have identified several classes of surfactants and surfactant
combinations that provide stable aqueous herbicidal concentrate
compositions for use in conjunction with the present invention.
[0033] In one embodiment, the surfactant comprises a quaternary
ammonium salt having the structure of formula (I):
##STR00005##
[0034] wherein R.sup.11 is hydrocarbyl or substituted hydrocarbyl
having from 1 to about 30 carbon atoms; R.sup.12 in each of the
(R.sup.12O).sub.x and (R.sup.12O).sub.y groups is independently
C.sub.2-C.sub.4 alkylene; R.sup.13 is hydrogen, or a linear or
branched alkyl group having from 1 to about 4 carbon atoms;
R.sup.14 is hydrocarbyl or substituted hydrocarbyl having from 1 to
about 30 carbon atoms; x and y are independently an average number
from 1 to about 40; and X.sup.- is an agriculturally acceptable
anion. In this context, preferred R.sup.11 and R.sup.14 hydrocarbyl
groups are linear or branched alkyl, linear or branched alkenyl,
linear or branched alkynyl, aryl, or aralkyl groups. Preferably,
R.sup.11 and R.sup.14 are independently a linear or branched alkyl
or linear or branched alkenyl group having from 1 to about 25
carbon atoms; R.sup.12 in each of the (R.sup.12O).sub.x and
(R.sup.12O).sub.y groups is independently C.sub.2-C.sub.4 alkylene;
R.sup.13 is hydrogen, methyl or ethyl; and the sum of x and y is an
average number from about 2 to about 30. More preferably, R.sup.11
and R.sup.14 are independently a linear or branched alkyl group
having from 1 to about 22 carbon atoms; R.sup.12 in each of the
(R.sup.12O).sub.x and (R.sup.12O).sub.y groups is independently
ethylene or propylene; R.sup.13 is hydrogen or methyl; and the sum
of x and y is an average number from about 2 to about 20. Even more
preferably, R.sup.11 is a linear or branched alkyl group having
from about 8 to about 22 carbon atoms; R.sup.14 is a linear or
branched alkyl group having from 1 to about 22 carbon atoms;
R.sup.12 in each of the (R.sup.12O).sub.x and (R.sup.12O).sub.y
groups is independently ethylene or propylene; R.sup.13 is hydrogen
or methyl; and x is an average number from about 2 to about 20.
Most preferably, R.sup.11 is a linear or branched alkyl group
having from about 8 to about 22 carbon atoms; R.sup.14 is a linear
or branched alkyl group having from 1 to about 6 carbon atoms;
R.sup.12 in each of the (R.sup.12O).sub.x and (R.sup.12O).sub.y
groups is independently ethylene or propylene; R.sup.13 is hydrogen
or methyl; and x is an average number from about 2 to about 15; or
R.sup.11 and R.sup.14 are independently a linear or branched alkyl
group having from about 8 to about 22 carbon atoms; R.sup.12 in
each of the (R.sup.12O).sub.x and (R.sup.12O).sub.y groups is
independently ethylene or propylene; R.sup.13 is hydrogen or
methyl; and x is an average number from about 5 to about 15.
[0035] One example of a preferred dialkoxylated quaternary ammonium
surfactants is ETHOQUAD C-12 (a cocoalkylmethylbis(2-hydroxyethyl)
ammonium chloride surfactant available from Akzo Nobel). In various
embodiments, the surfactant or surfactant system may include a
solvent or other additives. For example, when ETHOQUAD C-12 is
incorporated into the aqueous herbicidal concentrate composition,
it may be added as a mixture containing diethylene glycol (DEG) or
polyethylene glycol (PEG). Therefore, in certain embodiments, the
surfactant comprises ETHOQUAD C-12 dissolved in diethylene glycol
or polyethylene glycol (e.g., a mixture containing 75 wt. %
ETHOQUAD C-12 and 25 wt. % diethylene glycol or polyethylene
glycol). Other examples of preferred quaternary ammonium
surfactants that can be used to form stable aqueous glyphosate and
dicamba salt concentrate compositions are ARQUAD T27W and ARQUAD
C33W, which are available from Akzo Nobel.
[0036] In another embodiment, the surfactant comprises an
alkoxylated tertiary etheramine having the structure of formula
(II):
##STR00006##
wherein R.sup.1 is a hydrocarbyl or substituted hydrocarbyl having
from about 4 to about 22 carbon atoms; R.sup.2 and R.sup.3 are each
independently a hydrocarbylene having 2, 3, or 4 carbon atoms; each
R.sup.4 is independently hydrogen or C.sub.1-6 alkyl, m is an
average number from about 1 to about 10; and the sum of x and y is
an average value ranging from about 2 to about 60. R.sup.1 is
preferably an alkyl having an average value ranging from about 4 to
about 22 carbon atoms, more preferably from about 8 to about 22
carbon atoms, and still more preferably from about 10 to about 20
carbons atoms, for example coco, tallow, oleyl, and stearyl.
Sources of the R.sup.1 group include, for example, coco or tallow,
or R.sub.1 may be derived from synthetic hydrocarbyls, such as
decyl, dodedecyl, tridecyl, tetradecyl, hexadecyl, or octadecyl
groups. The number m is preferably from about 1 to 5, such as 2 to
3. R.sup.2 and R.sup.3 are preferably independently ethylene,
propylene, isopropylene, and are preferably ethylene. R.sup.4 is
preferably hydrogen. The sum of x and y is preferably an average
value ranging from about 2 to about 25.
[0037] One preferred example of an alkoxylated tertiary etheramine
surfactant is SURFONIC AGM 550 available from Huntsman
Petrochemical Corporation wherein R.sup.1 is C.sub.12-14, R.sup.2
is isopropyl, R.sup.3 is ethylene, R.sup.4 is hydrogen, m is 2 and
the sum of x and y is 5. Other examples of preferred alkoxylated
tertiary etheramine surfactants that can be used to form stable
aqueous glyphosate and dicamba salt concentrate compositions are
ETHOMEEN C-15, ETHOMEEN C-12, and AROMOX C12W, all available from
Akzo Nobel.
[0038] In order to sufficiently compatibilize and increase the
amount of an alkoxylated tertiary etheramine surfactant or
quaternary ammonium salt surfactant incorporated into the aqueous
herbicidal concentrate compositions of the present invention, it
may be useful to utilize a surfactant system comprising the
combination of an alkoxylated tertiary etheramine surfactant or
quaternary ammonium salt surfactant as described above with a
non-ionic alkylpolysaccharide (e.g., alkylpolyglucoside or APG)
surfactant. Alkylpolysaccharide surfactants are generally reported
to be less effective in enhancing herbicidal activity as compared
to cationic or amphoteric surfactants when used as the sole
surfactant component of solution concentrate formulations of a
glyphosate salt. Advantageously, however, it has been discovered
that the inclusion of an alkylpolysaccharide surfactant allows a
higher concentration of an alkoxylated tertiary etheramine
surfactant or quaternary ammonium salt surfactant to be
incorporated into the aqueous herbicidal concentrate composition to
take advantage of its improved efficacy in enhancing the herbicidal
effectiveness of the glyphosate and dicamba salts.
[0039] Suitable alkylpolysaccharide surfactants have the structure
of formula (III):
R.sup.5--O-(sug).sub.u (III)
wherein R.sup.5 is a straight or branched chain substituted or
unsubstituted hydrocarbyl selected from alkyl, alkenyl,
alkylphenyl, alkenylphenyl having from about 4 to about 22 carbon
atoms. The sug moiety is a saccharide residue, and may be an open
or cyclic (i.e., pyranose) structure. The saccharide may be a
monosaccharide having 5 or 6 carbon atoms, a disaccharide, an
oligosaccharide or a polysaccharide. Examples of suitable
saccharide moieties, including their corresponding pyranose form,
include ribose, xylose, arabinose, glucose, galactose, mannose,
telose, gulose, allose, altrose, idose, lyxose, ribulose, sorbose
(sorbitan), fructose, and mixtures thereof. Examples of suitable
disaccharides include maltose, lactose and sucrose. Disaccharides,
oligosaccharides and polysaccharides can be a combination of two or
more identical saccharides, for example maltose (two glucoses) or
two or more different saccharides, for example sucrose (a
combination of glucose and fructose). The degree of polymerization,
u, is an average number from 1 to about 10, from 1 to about 8, from
1 to about 5, from 1 to about 3, and from 1 to about 2. As known to
those skilled in the art, as depicted in formula (III), R.sup.5 is
linked to an oxygen atom of the sug moiety. In various particular
embodiments, the alkylpolysaccharide surfactant may be an
alkylpolyglucoside (APG) surfactant of formula (III) wherein:
R.sup.5 is a branched or straight chain alkyl group preferably
having from 4 to 22 carbon atoms, more preferably from 8 to 18
carbon atoms, or a mixture of alkyl groups having an average value
within the given range; sug is a glucose residue (e.g., a
glucoside); and u is from 1 to about 5, and more preferably from 1
to about 3. In various embodiments, the surfactant comprises an APG
of formula (III) wherein R.sup.5 is a branched or straight chain
alkyl group having from 8 to 10 carbon atoms or a mixture of alkyl
groups having an average value within the given range and u is from
1 to about 3.
[0040] Examples of surfactants of formula (III) are known in the
art. For example, one preferred surfactant is AGNIQUE PG8107-G
(AGRIMUL PG 2067) available from BASF.
[0041] Representative alkylpolysaccharide surfactants are presented
in the table below wherein for each surfactant sug in formula (III)
is a glucose residue.
TABLE-US-00001 Trade name R.sup.5 u APG 225 C.sub.8-12 alkyl 1.7
APG 325 C.sub.9-11 alkyl 1.5 APG 425 C.sub.8-16 alkyl 1.6 APG 625
C.sub.12-16 alkyl 1.6 GLUCOPON 600 C.sub.12-16 alkyl 1.4 PLANTAREN
600 C.sub.12-14 alkyl 1.3 PLANTAREN 1200 C.sub.12-16 alkyl 1.4
PLANTAREN 1300 C.sub.12-16 alkyl 1.6 PLANTAREN 2000 C.sub.8-16
alkyl 1.4 AGRIMUL PG 2076 C.sub.8-10 alkyl 1.5 AGRIMUL PG 2067
C.sub.8-10 alkyl 1.7 AGRIMUL PG 2072 C.sub.8-16 alkyl 1.6 AGRIMUL
PG 2069 C.sub.9-11 alkyl 1.6 AGRIMUL PG 2062 C.sub.12-16 alkyl 1.4
AGRIMUL PG 2065 C.sub.12-16 alkyl 1.6 BEROL AG 6202
2-ethyl-1-hexyl
[0042] In various embodiments, the aqueous herbicidal concentrate
composition contains at least about 1 wt. %, at least about 2 wt.
%, at least about 3 wt. %, at least about 4 wt. %, or at least
about 5 wt. % of surfactant. In these and other embodiments, the
aqueous herbicidal concentrate composition contains from about 1
wt. % to about 20 wt. %, from about 2.5 wt. % to about 20 wt. %,
from about 5 wt. % to about 20 wt. %, from about 2.5 wt. % to about
15 wt. %, from about 2.5 wt. % to about 10 wt. %, from about 5 wt.
% to about 15 wt. %, or from about 5 wt. % to about 15 wt. % of
surfactant.
[0043] In some embodiments, the aqueous herbicidal concentrate
composition contains at least about 5 wt. % of a quaternary
ammonium salt surfactant of formula (I) as described above. In
other embodiments, the aqueous herbicidal concentrate composition
contains a surfactant system comprising from about 5 wt. % to about
7.5 wt. % of an alkylpolyglucoside surfactant of formula (III) and
at least about 2.5 wt. % of an alkoxylated tertiary etheramine
surfactant of formula (II) as described above.
[0044] The aqueous herbicidal concentrate composition of the
present invention may be prepared by a process that includes adding
a dicamba salt or solution thereof to an aqueous solution
concentrate comprising the glyphosate salt.
[0045] In various embodiments, the glyphosate salt solution
concentrate contains glyphosate that is neutralized using a molar
excess of base to fully neutralize the acidic site of glyphosate
having the lowest pKa, but less than two molar equivalents of base
to glyphosate (e.g., prepared using 1.3 molar equivalents of base
to neutralize 1.3 acidic sites of glyphosate). Accordingly, in
various embodiments glyphosate salt solution concentrates may be
prepared using molar equivalents of neutralizing base to glyphosate
from about 1:1 to about 1.5:1, from about 1.1:1 to about 1.5:1,
from about 1.2:1 to about 1.5:1, from about 1.25:1 to about 1.5:1,
from about 1:1 to about 1.4:1, from about 1.2:1 to about 1.4:1,
from about 1.25:1 to about 1.4:1, or from about 1.25:1 to about
1.35:1. The glyphosate salt concentrate can be prepared by adding
additional neutralizing base corresponding to the relevant
glyphosate salt to an existing aqueous glyphosate salt solution
concentrate. Additional water may be added as necessary in order to
maintain the glyphosate salt in solution. Alternatively, the
glyphosate salt concentrates can be prepared by adding the
neutralizing base directly to glyphosate acid wetcake and then
dissolving the mixture of wetcake and base in water.
[0046] Off-site movement is a known problem of spray formulations
containing salts of dicamba. Under certain conditions of
application, dicamba can migrate from the application site to
adjacent crop plants. As noted above, as pH increases, the
volatility of dicamba generally decreases. In accordance with the
present invention, it has been discovered that significant
decreases in dicamba volatility are realized when the pH of the
aqueous herbicidal glyphosate and dicamba salt concentrate
composition is controlled as described above. Additional base can
be added as necessary to the glyphosate salt solution concentrate
and/or aqueous herbicidal glyphosate and dicamba salt concentrate
composition as necessary to adjust the pH within the desired range
as disclosed herein. Adjusting the pH within the disclosed ranges
typically provides greater than about a 40%, 50%, 60% or even 75%
reduction in volatility when compared to a conventional tank mixes
of potassium or monoethanolamine glyphosate with diglycolamine salt
of dicamba (e.g., a tank mix of CLARITY available from BASF and
ROUNDUP WEATHERMAX available from Monsanto).
[0047] One or more surfactants or surfactants or surfactant systems
as described above may be introduced at any step of the preparation
process. In various embodiments, the surfactant is added once the
dicamba and glyphosate salts have been combined in the concentrate
solution. In other embodiments, the surfactant can be added to the
dicamba salt solution before adding to the aqueous glyphosate salt
solution concentrate.
[0048] The aqueous herbicidal concentrate compositions containing
glyphosate salt and dicamba salt of the present invention are
typically formulated to exhibit good storage stability at
relatively low temperatures, relatively high temperatures, and/or
over a wide temperatures range such that the compositions remain
relatively clear without precipitation or phase separation after
prolonged storage. In various embodiments, the concentrate
compositions exhibit good storage stability at a temperature of
less than about 0.degree. C., less than about -10.degree. C., less
than about -20.degree. C., or less than about -20.degree. C.
Additionally or alternatively, the concentrate compositions exhibit
good storage stability at a temperature of at least about
25.degree. C., at least about 40.degree. C., at least about
55.degree. C., or at least about 60.degree. C. In various
embodiments, the concentrate compositions exhibit good storage
stability from about -30.degree. C. to about 80.degree. C., from
about -30.degree. C. to about 70.degree. C., from about -30.degree.
C. to about 60.degree. C., from about -10.degree. C. to about
90.degree. C., from about -10.degree. C. to about 70.degree. C.,
from about -10.degree. C. to about 60.degree. C., from about
0.degree. C. to about 90.degree. C., from about 0.degree. C. to
about 70.degree. C., or from about 0.degree. C. to about 60.degree.
C. In these embodiments, the concentrate compositions exhibit good
storage stability over the period of at least about one week, at
least about two weeks, at least about three weeks, or at least
about four weeks.
[0049] The herbicidal concentrate compositions may further comprise
other conventional adjuvants, excipients or additives known to
those skilled in the art. These other additives or ingredients may
be introduced into the compositions of the present invention to
provide or improve certain desired properties or characteristics of
the formulated product. Hence, the herbicidal concentrate
composition may further comprise one or more additional ingredients
selected from, without limitation, foam-moderating agents,
preservatives or anti-microbials, antifreeze agents,
solubility-enhancing agents, dyes, and thickening agents. For
example, in various embodiments the aqueous herbicidal concentrate
composition includes a foam-moderating agent such as SAG 1572 (a
silicone antifoam emulsion available from Momentive). Typically the
concentration of foam-moderating agent in the aqueous herbicidal
concentrate composition is less than about 0.1 wt. % or less than
about 0.05 wt. % (e.g., about 0.01 wt. %)
[0050] The aqueous herbicidal glyphosate and dicamba concentrate
composition may be diluted with water and applied to the foliage of
unwanted plants as a spray formulation solution by methods known in
the art. In accordance with the methods of using a formulation of
the present invention, an application mixture comprising a dilution
of the aqueous herbicidal concentrate composition may be prepared,
which typically comprises from about 0.1 to about 50 g a.e./L
herbicide active. The application mixture is then applied to the
foliage of a plant or plants at an application rate sufficient to
give a commercially acceptable rate of weed control. Depending on
plant species and growing conditions, the period of time required
to achieve a commercially acceptable rate of weed control can be as
short as a week or as long as three weeks, four weeks or 30 days.
The application rate is usually expressed as amount of herbicide
per unit area treated, e.g., grams acid equivalent per hectare (g
a.e./ha) and can readily be determined by those skilled in the
art.
[0051] The application mixture comprising a dilution of the aqueous
herbicidal concentrate composition of the present invention can be
applied pre-planting of the crop plant, such as from about 2 to
about 3 weeks before planting glyphosate and dicamba-susceptible
crop plants or crop plants not having a dicamba-resistant trait.
Crop plants that are not susceptible to glyphosate and dicamba
herbicides, such as corn, or plants having glyphosate-tolerant and
dicamba-tolerant traits typically have no pre-planting restriction
and the application mixture can be applied immediately before
planting such crops.
[0052] The application mixture comprising a dilution of the aqueous
herbicidal glyphosate and dicamba salt concentrate composition of
the present invention can be applied at planting or post-emergence
to crop plants having glyphosate-tolerant and dicamba-tolerant
traits to control glyphosate and/or dicamba-susceptible weeds in a
field of the crop plants and/or adjacent to a field of the crop
plants.
EXAMPLES
[0053] The following non-limiting examples are provided to further
illustrate the present invention.
Example 1
[0054] Various aqueous herbicidal concentrate compositions
containing glyphosate salt and dicamba salt were prepared by adding
the desired base (e.g., monoethanolamine (MEA), isopropylamine
(IPA) or potassium hydroxide) to stock glyphosate salt solutions.
Salt solutions of dicamba (e.g., diglycolamine (DGA), MEA, and K
salts) were added to the glyphosate salt solutions to the desired
acid equivalent weight ratio (e.g., glyphosate to dicamba weight
ratios of 3:1, 2:1, or 1.5:1).
[0055] The solutions which provided stable, compatible herbicidal
concentrate compositions upon mixing are listed below in Table
1.
TABLE-US-00002 TABLE 1 Weight ratio a.e. Total herbicide Glyphosate
Dicamba (Glyphosate/ loading salt salt Dicamba) (g/l a.e.) MEA DGA
3:1 480 MEA MEA 3:1 480 MEA K 3:1 480 IPA DGA 3:1 360 IPA MEA 3:1
360 IPA K 3:1 360 K DGA 3:1 220 K MEA 3:1 80 K K 3:1 80 MEA DGA 2:1
480 MEA MEA 2:1 480 MEA K 2:1 480 IPA DGA 2:1 330 IPA MEA 2:1 330 K
DGA 2:1 330 K MEA 2:1 330 MEA DGA 1.5:1.sup. 480 MEA MEA 1.5:1.sup.
480 MEA K 1.5:1.sup. 480
Example 2
[0056] To evaluate whether surfactant(s) could be effectively
incorporated into the aqueous herbicidal concentrate compositions
of the present invention, several concentrate solutions containing
MEA glyphosate and DGA dicamba and having a total herbicidal
loading of approximately 480 g/l a.e. were prepared as described in
Example 1, except various surfactants were combined the solution
concentrates. The stability of the solutions was observed upon
mixing and any precipitation or phase separation was noted. The
stability of the solutions that appeared relatively homogeneous
upon mixing was tested further by storing them at room temperature
for 24 hours. Any precipitation or phase separate was noted after
the 24 hour time period. Table 2 presents the results of these
experiments.
TABLE-US-00003 TABLE 2 Surfactants combined with concentrates
containing approx. 480 g/l a.e. of MEA glyphosate salt and DGA
dicamba salt. Weight Stable ratio a.e. Surfactant concentrate after
(Glyphosate/ (wt. % in Cloud 24 hours? Dicamba) solution) point
(Yes/No) .sup. 3:1 5 wt. % APG & -- No 2.5 wt. % AGM 550 .sup.
3:1 7.5 wt. % APG & -- No 2.5 wt. % AGM 550 .sup. 2:1 5 wt. %
Ethoquad C-12 -- No .sup. 2:1 5 wt. % APG & >90.degree. C.
Yes 2.5 wt. % AGM 550 1.5:1 5 wt. % Ethomeen C-12 -- No 1.5:1 5 wt.
% Ethoquad C-12 >90.degree. C. Yes 1.5:1 5 wt. % Ethomeen SV-12
52.degree. C. No 1.5:1 5 wt. % Ethomeen T-12 70.degree. C. No 1.5:1
5 wt. % APG & >90.degree. C. Yes 2.5 wt. % AGM 550
[0057] The results show that stable, clear herbicidal concentrates
containing surfactant Ethoquad C-12 or surfactant system APG and
AGM 550 were successfully prepared. The other surfactants tested
resulted in concentrates that were either hazy in appearance or
separated into phases on standing.
Example 3
[0058] To evaluate whether higher concentrations of surfactant(s)
could be effectively incorporated into the aqueous herbicidal
concentrate compositions of the present invention, concentrate
solutions containing a 1.5:1 weight ratio of MEA glyphosate and DGA
dicamba and having a total herbicidal loading of approximately 480
g/l a.e. were prepared in accordance with Example 1. Ethoquad C-12
dissolved in propylene glycol or diethylene glycol was then
combined with the concentrates. The stability of the solutions was
observed and any precipitation or phase separation was noted. Table
3 presents the results of these experiments.
TABLE-US-00004 TABLE 3 Stable Ethoquad C-12 concentrate (wt. % in
Cloud formed? solution) Solvent point (Yes/No) 7.5 Diethylene
>90.degree. C. Yes Glycol 10 Diethylene 85.degree. C. Yes Glycol
7.5 Propylene >90.degree. C. Yes Glycol 10 Propylene -- No
Glycol
[0059] The results show that stable, clear herbicidal concentrates
containing surfactant 10 wt. % Ethoquad C-12 dissolved in
diethylene glycol were successfully prepared. The concentrate
containing 10 wt. % Ethoquad C-12 dissolved in propylene glycol
separated on standing.
[0060] Other surfactants were also tested with this concentrate
solutions containing a 1.5:1 weight ratio of MEA glyphosate and DGA
dicamba and having a total herbicidal loading of 480 g/l a.e.,
including Armeen APA 810, Ammonyx 810-DO, Surfonics L12-8, L14-4
and L24-5, Tergitol 15-S-7 and Tomadol 1-3. However, concentrates
containing these surfactants were either hazy in appearance or
separated into phases on standing.
Example 4
[0061] To test the storage stability of the concentrate
compositions, samples of selected concentrate compositions
containing approximately 480 g/l a.e. of MEA glyphosate salt and
DGA dicamba salt prepared in accordance with Example 2 were
subjected to prolonged storage for four weeks at various storage
temperatures. Table 4 shows that the selected concentrate
compositions exhibited good storage stability, remaining relatively
clear without precipitation or phase separation, after four weeks
at the temperatures indicated below.
TABLE-US-00005 TABLE 4 Weight ratio a.e. (Glyphosate/ Surfactant
Dicamba) (wt. % in solution) -30.degree. C. -20.degree. C.
-10.degree. C. 0.degree. C. 25.degree. C. 40.degree. C. 55.degree.
C. 60.degree. C. 1.5:1.sup. None S S S S S S S S 2:1 None S S S S S
S S S 3:1 None S S S S S S S S 1.5:1.sup. 5 wt. % Ethoquad S S S S
S S S S C-12 1.5:1.sup. 5 wt. % APG & 2.5 S S S S S S S S wt. %
AGM 550 2:1 5 wt. % APG & 2.5 S S S S S S S S wt. % AGM 550 3:1
7.5 wt. % APG & S S S S S S S S 2.5 wt. % AGM 550 S: denotes
that concentrate composition was "stable"
Example 5
[0062] This example describes experiments conducted to measure the
dicamba concentration in the gas phase (air) volatilized from 2 wt.
% a.e. dicamba spray solutions prepared from concentrates
containing MEA glyphosate and DGA dicamba and having a total
herbicidal loading of 480 g/l a.e. prepared in accordance with
Example 1 and prior art tank mix spray solutions containing 2 wt. %
a.e. DGA dicamba (CLARITY) plus 6 wt. % a.e. potassium glyphosate
(WEATHERMAX) or MEA glyphosate.
[0063] 10 mL samples of each solution were placed into a 50 mL
plastic centrifuge tube with one hole approximately 1/8 in diameter
drilled into the tube at the mark between 20 mL and 30 mL lines. A
22 mm.times.30 mm Polyurethane Foam (PUF), cut from a 76 mm length,
available from SKC Inc., catalog #P22692, was placed into a glass
tube of approximately 20 mm diameter with parafilm wrapped around
the outside to obtain a snug fit into the top of the centrifuge
tube. A hose was connected to the other end of the glass tube
leading to a vacuum line. The air flow was regulated to
approximately 2 L/min using a flow controller. Air was pulled
through the tube at approximately 2 L/min for 24 hours. Note that
the air conditions of flow rate, temperature, pressure and
composition (e.g., relative humidity) are not narrowly critical as
long as the various samples are analyzed under similar conditions.
For instance, air at from about 5.degree. C. to about 40.degree.
C., from about 0.5 to about 1.5 bar pressure, from about 0% to
about 95% relative humidity, and at a flow rate of from about 0.1
to 10 L/min-mL sample could be suitably used for volatility
analysis. The PUF was removed from the glass tube, extracted with
20 mL methanol and the resulting solution analyzed for dicamba
concentration by LC-MS. The results are presented in Table 5.
TABLE-US-00006 TABLE 5 Dicamba, Formulation ng/L Std dev CLARITY +
MEA glyphosate 1.89 0.49 CLARITY + WEATHERMAX 1.63 0.48 3:1
MEAgly:DGAdc 1.97 0.11 2:1 MEAgly:DGAdc 1.15 0.12 1.5:1
MEAgly:DGAdc 0.97 0.15
[0064] As shown on Table 5, the spray solutions prepared from
concentrates having a 2:1 or 1.5:1 weight ratio of glyphosate to
dicamba exhibited lower dicamba volatility when compared to prior
art spray solutions of CLARITY plus WEATHERMAX and CLARITY plus MEA
glyphosate.
Example 6
[0065] Five glyphosate/dicamba premix concentrate formulations were
prepared using five different MEA glyphosate salt solution
concentrates. The MEA glyphosate salt solution concentrates
employed were prepared using different molar ratios of
MEA:glyphosate. The molar ratios that were used were 1.2:1, 1.25:1,
1.3:1, 1.35:1, and 1.4:1 MEA:glyphosate. To form the
glyphosate/dicamba premix concentrate formulations, MEA glyphosate
salt concentrate, CLARITY (DGA dicamba salt concentrate) and water
were combined in a beaker. AGNIQUE PG8107 (a C.sub.8-10 alkyl
polyglycoside surfactant available from COGNIS) and AGM 550 (a
C.sub.12-14 alkoxylated tertiary available from Huntsman) were
added followed by ferric citrate and SAG 1572 (a silicone antifoam
emulsion available from Momentive). The ingredients were stirred
together for 30 minutes. The list of ingredients for the
glyphosate/dicamba premix concentrate formulations is set forth
below in Table 6.
[0066] The following observations/tests were performed on the
glyphosate/dicamba premix concentrate formulations: appearance,
specific gravity, cloud point, temperature stability at 55.degree.
C. and -20.degree. C. and pH, and are reported below in Tables 7
and 8.
TABLE-US-00007 TABLE 6 List of ingredients and amounts Ingredient
Amount CLARITY 12.75% a.e. MEA glyphosate 25.5% a.e. AGNIQUE PG
8107 5% w/w SURFONIC AGM 550 2.5% w/w Ferric citrate 220 ppm Fe SAG
1572 100 ppm
TABLE-US-00008 TABLE 7 Summary of observations and measurements
performed on the formulations MEA:glyphosate acid molar Specific
Cloud Formulation ratio Appearance gravity Point 8-1 1.2:1 Cloudy,
2 Not Not layers on measured measured standing 8-2 1.25:1 Dark
green, 1.2599 >90.degree. C. clear/hazy liquid 8-3 1.3:1 Dark
green, 1.2598 >90.degree. C. clear liquid 8-4 1.35:1 Dark green,
1.2612 >90.degree. C. clear liquid 8-5 1.4:1 Dark green, 1.2637
>90.degree. C. clear liquid
[0067] For the formulation prepared using the 1.2:1 MEA:glyphosate
concentrate, when MEA glyphosate salt concentrate, CLARITY, and
water were mixed, a clear green liquid formed. The salts themselves
were compatible at that pH. Upon addition of the surfactants, the
liquid turned hazy and 2 layers formed on standing. The formulation
prepared using the 1.25 MEA:glyphosate concentrate was slightly
hazy, but cleared on heating when the cloud point was measured. For
the temperature stability study all of the formulation samples at
-20.degree. C. were viscous liquids. The formulation samples at
55.degree. C. were all clear liquids. In the formulation sample
prepared using the 1.25 MEA:glyphosate concentrate, there were
slight wisps, probably surfactant, that were observed.
[0068] The pH of each premix concentrate formulation was measured.
The pH measurements were made using a Mettler Toledo model
SevenEasy pH meter with a Thermo Scientific ROSS Sure-flow pH
probe. The pH meter was calibrated in accordance with the
manufacturer's recommended protocol at pH 4 and pH 7 using standard
buffer solutions (available from BDH). The pH measurements were
obtained by immersing the probe of calibrated pH meter into each
concentrate formulation and recording the digital reading.
[0069] Some samples of concentrate may exhibit sample matrix
effects which have a negative interaction with pH electrodes. To
determine if a sample causes an interaction, a calibration should
be performed prior to sample analysis. During sample analysis, the
response time to obtain a stable pH reading should be observed.
Then, the response time and pH reading of the two buffers used for
calibration should be rechecked. If the pH reading of the
calibration buffers has a significant difference and the electrode
response is slow (e.g., >20 seconds), a negative interaction of
the pH electrode and sample is occurring. Different electrode
should be tested until sample matrix effects are not observed.
[0070] To avoid clogging of the electrode junction, the electrode
should be flushed with deionized water after each sample
analysis.
[0071] Table 8 shows the pH measurements for each premix
formulation tested.
TABLE-US-00009 TABLE 8 (MEA:glyphosate acid molar pH Formulation
ratio) measured 8-2 1.25:1 5.01 8-3 1.3:1 5.11 8-4 1.35:1 5.25 8-5
1.4:1 5.37
Example 7
[0072] Selected premix concentrate formulations prepared in
accordance with Example 6 were tested for dicamba volatility using
the humidome method as described below. The formulations were
compared to BANVEL (dimethylamine dicamba salt solution)+ROUNDUP
WEATHERMAX, CLARITY+ROUNDUP WEATHERMAX, and CLARITY alone.
[0073] Humidomes were obtained from Hummert International (Part Nos
14-3850-2 for humidomes and 11-3050-1 for 1020 flat tray) and
modified by cutting a 2.2 cm diameter hole on one end approximately
5 cm from the top to allow for insertion of a glass air sampling
tube (22 mm OD) containing a polyurethane foam (PUF) filter. The
sampling tube was secured with a VITON o-ring on each side of the
humidome wall. The air sampling tube external to the humidome was
fitted with tubing that was connected to a vacuum manifold
immediately prior to sampling.
[0074] The flat tray beneath the humidome was filled 1 liter of
sifted dry or wet 50/50 soil (50% Redi-Earth and 50% US 10 Field
Soil) to a depth of about 1 cm. The flat tray bottom containing the
dicamba formulation on soil was covered with a humidome lid and the
lid was secured with clamps. The assembled humidomes were placed in
a temperature and humidity controlled environment and connected to
a vacuum manifold through the air sampling line. Air was drawn
through the humidome and PUF at a rate of 2 liters per minutes
(LPM) for 24 hours at which point the air sampling was stopped. The
humidomes were then removed from the controlled environment and the
PUF filter was removed. The PUF filter was extracted with 20 mL of
methanol and the solution was analyzed for dicamba concentration
using LC-MS methods known in the art.
[0075] To measure the dicamba concentration in the gas phase (air)
volatilized from the spray solutions, solutions were prepared to
contain 1.2% a.e. dicamba which is equivalent to an application
rate of 1.0 lb/A a.e. at 10 GPA. Where glyphosate was added or was
part of the formulation, the solution was sprayed at 2.4% a.e. or
2.0 lb/A a.e. The growth chambers were set at 35.degree. C. and 40%
RH. For each formulation four separate humidome boxes were sprayed
to have 4 replicates measurements for each formulation. Table 9
also provides the mean concentration of dicamba in air for each
formulation.
TABLE-US-00010 TABLE 9 Dicamba, Std Formulation ng/L Std dev error
BANVEL + WEATHERMAX 5.26 0.94 0.33 CLARITY + WEATHERMAX 2.39 0.50
0.19 8-2 1.38 0.28 0.14 8-3 1.01 0.31 0.15 8-4 0.70 0.12 0.04 8-5
0.48 0.06 0.03 CLARITY 0.13 0.01 0.00
[0076] The results show that the spray solutions prepared from
premix concentrate formulations 8-2, 8-3, 8-4, and 8-5 exhibited
significantly lower dicamba volatility when compared to prior art
spray solutions of BANVEL plus WEATHERMAX and CLARITY plus
WEATHERMAX.
[0077] When introducing elements of the present invention or the
preferred embodiments(s) thereof, the articles "a", "an", "the" and
"said" are intended to mean that there are one or more of the
elements. The terms "comprising", "including" and "having" are
intended to be inclusive and mean that there may be additional
elements other than the listed elements.
[0078] In view of the above, it will be seen that the several
objects of the invention are achieved and other advantageous
results attained.
[0079] As various changes could be made in the above compositions
and processes without departing from the scope of the invention, it
is intended that all matter contained in the above description
shall be interpreted as illustrative and not in a limiting
sense.
* * * * *