STRUCTURING AGENTS AND EMULSIFIERS FOR AGRICULTURAL
OIL-BASED FORMULATIONS
Field of the Invention
This invention relates to the stabilisation of oil-based suspension formulations of
agriculturally active finely divided solids. More particularly, the invention relates to oilbased
suspension formulations comprising an agriculturally active solid having improved
stability.
Background of the Invention
Formulations comprising an agriculturally active solid suspended in an oil, as the primary
component of the continuous phase, have been found advantageous in the treatment of
agricultural substrates. Examples of such formulations have been designated by CropLife
International as OD ("oil dispersion") and OF ("oil-miscible flowable concentrate")
formulations.
Such formulations provide certain advantages to the end user. They allow the formulation
of active ingredients in solid suspended form, which ingredients cannot be formulated in
water because of hydrolytic instability. Also, such formulations allow oil-based adjuvants
to be incorporated into the formulation to enhance efficacy. Further, in many cases active
ingredients have a solubility limit on the amount that can be loaded into a formulation,
such as an emulsifiable concentrate formulation, and so suspension in an oil-based system
can possibly lead to higher active ingredient strength formulations than would otherwise be
possible.
A major limitation on an oil-based agricultural formulation, such as an OD and OF
formulation, is the need to physically stabilize the formulation for potentially long periods
of storage, so that it can be in a consistently useable form for later end use. Typically, an
OD or OF formulation can exhibit sedimentation of the active ingredient particles over
time into a hard-packed non-redispersible layer, or settling of the particles into the lower
layers of the liquid column leading to the appearance of phase separation. This is what is
commonly tamed "syneresis". Depending on the density of the active ingredient and that
of the oil phase used, it is also possible to find the active ingredient particles migrating to
the top layers of the liquid column. This is often described as "reverse" or "top" syneresis.
Such physical instability can occur regardless of the presence of an oil-based surfactant
dispersant, which is designed to prevent flocculation of the dispersed particles.
In order for a stabilizer to be useful in an oil-based agricultural suspension, it must provide
o long term physical stability across a wide temperature range, normally 0 C to 54 C, while
still maintaining a viscosity low enough to be practical for production of the formulation
and its later end use. A typical viscosity required would be less than 2,000 centipoise
("cP") and preferably, less than 1200cP.
Various methods of stabilization of oil-based formulations are known. Typical stabilizers
currently used for oil-based formulations include organically modified hectorite clay, such
as the Bentone® range available from Elementis Specialties. In many of the systems that
have been tested, the present inventors have found that these stabilizers do not appear to
always impart stability across the desired temperature range on accelerated storage at an
acceptable viscosity. Further, the thickeners used in some cases appear to inhibit some
common non-aqueous dispersants used.
Hydrophobically-modified silicas are also currently used in the art. However, such
stabilizers are limited in that the degree of hydrophobicity required cannot always be
adequately tuned to that of the oil used. Further, such stabilizers often require the use of a
small amount of hydrophilic agent, such as water, to help form a thickening structure in the
oil phase. The use of water with silica in many cases negates the purpose of the
formulation being anhydrous to avoid chemical degradation of the active ingredient. In
many cases, the amount of silica stabilizer required to prevent undesirable sedimentation
also leads to a formulation that is highly viscous and impractical to use.
Further, difficulty has been experienced in stabilizing certain active ingredients at their
most desirable concentrations. Accordingly, there is a need for improved stabilizers for oilbased
agricultural suspension formulations.
The present invention seeks to provide an improved stabilized oil-based agricultural
suspension formulation and a method for producing the same. More particularly, the
present invention seeks to minimize or ameliorate disadvantages and problems found in the
prior art.
Summary of the Invention
While it is known that polyalkylene glycol-fatty acid poly condensate block co-polymer
surfactants can be used as dispersing agents for oil-based systems and that such surfactants
can also act as emulsifying agents for both oil-in-water and water-in-oil systems, it has
now been unexpectedly found that a particular range of these surfactants, when used alone
or in combination, can also act as structuring agents for agrochemical oil-based
formulations, while still maintaining their dispersant and emulsifying functions. The
present inventors have surprisingly identified certain polyalkylene glycol-fatty acid
condensates and polyalkylene glycol ether-fatty acid poly condensate block copolymers
which, when used according to the methods described herein, can afford greatly improved
physical stability for an oil-based agricultural formulation, such as an OD or an OF
formulation.
According to one aspect of the present invention, there is provided an agricultural oil-based
suspension formulation comprising an active ingredient suspended in finely divided form
in an oil; and at least one surfactant selected from a polyalkylene glycol-fatty acid
condensate or a polyalkylene glycolether fatty acid condensate formed from a reaction
between a com ound having Structure (1) and a compound having Structure (2):
wherein Ri = H or a -C3 alkyl radical;
A and B are ethylene or propylene groups in succession or random;
n = 0 or>l; and
m=0 or >1,
and wherein n+m > 34;
R.2 = C8-C30 alkyl or alkylene radical (branched or linear); and
x = >1.
More preferably, the surfactant is a diblock condensate of polyethylene glycol having a
molecular weight of greater than 1500amu and a polyhydroxystearic acid copolymer of
condensation range greater than 2 units as per Structure (2). In its most preferred form, the
surfactant comprises at least one monoblock condensate of a polyalkylene glycol etherfatty
acid condensate, wherein the polyalkylene glycol ether is an ethylene oxide-propylene
oxide copolymer butyl ether having a molecular weight of greater than 1800amu and the
fatty acid condensate is a polyhydroxystearic acid copolymer of condensation range greater
than 2 units.
T e preferred use rate of the polyalkylene glycol-fatty acid condensate or polyalkylene
glycolether fatty acid condensate ranges from 2-10% w/v in the formulation and more
preferably, 3-8%, depending on the active ingredient loading and the type of oi used in the
formulation. At such levels, substantial stabilization to sedimentation and flocculation
may be observed. In most cases, the condensate will be used in conjunction with another
surfactant. The degree to which the condensate contributes to the dispersant effect in the
formulation is dependent on the type and amount of surfactant used.
The active ingredient suitable for inclusion in an OD formulation preferably comprises at least
one fungicide, insecticide, herbicide, plant growth regulator, miticide, nematocide,
molluscicide, algicide, or other pesticide, or mixtures thereof. More particularly, the active
ingredient is selected from, but not limited to, a fungicide, such as an alkylene
bis(dithiocarbamate), such as Mancozeb (i.e. ethyienebisdithiocarbamate complex with Mg
and Zn); Zineb (Le. zinc(ethylenebis dithiocarbamate)polymer or Ziram (Le. zinc
bis(dimethyI-dithiocarbamate); Fosetyl-aluminium (Le. aluminium tris-O-ethylphosphonate);
Tebuconazole (Le. fRS)-l-(4-clilorophenyl)-4,4-dimemyl-3-(lH-l,2,4-triazo-l-ylmethyl)-
pentan-3-ol); copper hydroxide; and copper oxychloride; a phthalimide, such as Captan (Le.
N-(tricUoromemylmio)-cyclohex-4-ene-l,2-dicari)oximide); a herbicide, such as a sulphonyl
urea, for example, Nicosulfuron (Le. 2-[(4,6-dimemoxypyrimidin-2-ylcarbamoyl)sulfamoyl]-
N,^-dimemylm^otinamide); and Azimsulfuron (Le. l-(4,6-dimethoxypyrimidin-2-yl)-3-[lmethyl-
4-(2-methyl-2H-tetrazol-5-yl)pyrazol-5-yl sulfonyl] urea); triazolopyrimidines, such
as FTumetsulam (Le. 2^6'-difluoro-5-memyl[l,2,4]triazolo[l,5-a]pyrimidine-2-sulfonanU
and Penoxsulam (Le. 2-(2,2-difluoroemoxy)-N-(5,8-dmiethoxy[l,2,4]triazolo[l,5-
c]pyrimidm-2-yl)-6-(trifluoro-methyl)benzenesulfonamide); a triazine, such as Atrazine (Le.
-chloro-N-emyl-N'-il-memylemyO-l.S.Srtriazme^^-diamine); a phenyl urea herbicide,
such as Diuron (i.e.3-(3,4-dichlorophenyl)-l,l-dimethylurea); an insecticide, such as Aldicarb
(Le. 2-me±yl-2-(memylmio)propionaldehyde-0-memylcarbamoyloxime); Carbaryl (Le. 1-
naphthyl methylcarbamate); and Diflubenzuron (i.e. N-[[(4-chlorophenyl)- amino]carbonyl]-
2,6-difluorobenzamide).
Prior to an OD formulation being broadcast normally via foliar spray, it is diluted in water.
For an OF formulation, the formulation is designed to be further diluted in an oil and
therefore surfactant emulsifiers are not required. The formulation is otherwise similar to an
OD formulation. It is a requirement of an OD formulation that the active ingredient be
present in a finely divided state in an oil. Suitable oil phases for OD and OF formulations
include any liquid at ambient temperature, which does not dissolve the active ingredient
enough to cause crystal growth or physical instability.
The oil phase may comprise, but is not limited to, a paraffin oil, such as a kerosene, for
example one of the EXXSOL® D range available from Exxon Chemical, more preferably,
EXXSOL® D130; and HYDROSEAL® G250H available from Total. Seed oil esters, such
as methyl and ethyl oleate, methyl and ethyl soyate and their corresponding fatty acids are
also suitable. Aromatic hydrocarbons, such as alkyl benzenes and alkylnaphthalenes,
polyalkylene glycol ethers, fatty acid diesters, fatty alkylamides and diamides, ketones and
alcohols may also be suitable.
The suspension formulation of the invention may comprise further additives, such as a
surfactant emulsifying agent to be added once the active ingredient has been suspended in
the oil; to allow the oil phase to be delivered in an emulsified form; a surfactant dispersant
and physical stability agents other than those of the invention, which may function as antisettling
or anti-syneresis agents. Where present, the surfactant dispersant can be included
in any suitable amount up to the level required for colloidal stabilization of the solid phase
after milling.
A surfactant dispersant suitable for OD and OF formulations is preferably selected from,
but is not limited to, fatty acid-polyethylene glycol condensates such as TERSPERSE®
2510 dispersant; polyamine-fatty acid condensates, such as TERSPERSE® 4890
dispersant; random polyester condensates, such as TERSPERSE ® 2520 dispersant; and
salts of polyolefin condensates, such as TERSPERSE® 2422 dispersant, which are all
products of Huntsman Corporation.
The choice of emulsifiers for the OD formulation tends to be dictated by the oils used.
Generally, surfactants with a low hydrophobe-lipophobe balance ("HLB") are suitable.
Such surfactants are preferably selected from, but are not limited to, one or more of
ethoxylated fatty alcohols, sorbitan esters and their corresponding ethoxylates, ethoxylated
fatty acids, ethoxylated castor oil, calcium and ammonium salts of alkylbenzene
sulphonate, alkylsulphosuccinate salts, ethylene oxide-propylene oxide block copolymers,
ethoxylated alkylamines and ethoxylated alkyl phenols. The emulsifiers for an OD
formulation comprising Mancozeb as the active ingredient can be selected from the groups
of castor oil ethoxylates, in particular TERMUL® 3512 emulsifier, alcohol ethoxylates in
particular TERIC® 12A3, 12A4 and 17A2 fatty acid ethoxylates, sorbitan ester ethoxylates,
such as ECOTERIC® T85 fatty acid ethoxylate, a sulphosuccinate, such as TERMUL®
366S emulsifier, amine and calcium salts of dodecylbenzene sulphonate, such as the
NANSA®EVM range of products, all of which are available from Huntsman Corporation.
The OD formulation may further comprise physical stability agents other than those of the
invention, which may function as anti-settling or anti-syneresis agents. Of particular utility
are the so-called rubber-type copolymers. Examples of such polymers include the
KRATON® polymer range, which are available from Kraton Polymers. Most preferred are
the KRATON® G series polymers, such as KRATON® G-1701 polymer.
Further additives which may be added to the formulation include colorants such as
pigments and dyes, adjuvant surfactants, pH and other chemical stabilizers, defoamers,
perfumes, odour masks and further density-adjusting solvents. The formulation may further
comprise safeners.
The scope of the present invention also extends to a method of preparing an OD
formulation comprising an active ingredient comprising the steps of:
a) preparing a surfactant solution premix by combining at least one surfactant
selected from a polyalkylene glycol-fatty acid condensate or a polyalkylene
glycolether fatty acid condensate of the present invention with a surfactant and an
oil to give a liquid;
b) dispersing the active ingredient in the surfactant solution by either stirring or high
shear mixing;
c) milling the active ingredient dispersion to achieve a particle size average in the
range 1-12 microns;
d) adding surfactant emulsifying agents; and
e) optionally adjusting the final concentration of active ingredient content by adding
additional oil and other required ingredients,
wherein steps a) to d) are carried out in any order.
In one preferred aspect, step (e) of the above method includes the addition of a rubber-type
copolymer as an additional anti-settling agent.
In one preferred embodiment of the present invention, the active ingredient comprises
Mancozeb, preferably in a concentration of greater than 400g/L. In another preferred form,
the formulation comprises Mancozeb in a concentration greater than 580g/L. The present
inventors have advantageously been able to produce a formulation comprising Mancozeb in a
concentration of greater than 480g/L, which formulation has been found to be stable longterm
with no adverse effects on viscosity. In this formulation, no hard-packed layer is
observed and the formulation remains fluid/pourable when stored for a time period of longer
than 2 weeks at 54°C. The advantage provided by the present invention is that it achieves a
superior stable high loading suspension formulation of Mancozeb, where alternative antisettling
agents, such as modified hectorite clays, appear to be ineffective. The formulation
also affords excellent ease of dispersibility into water and results in a stable emulsion and
suspension.
Once formulated, an OD or OF formulation produced by the method of the present
invention would be expected to show stability on storage at temperatures ranging from
-5°C to 54°C for up to 2 weeks and also stability at ambient temperature for up to 2 years.
Detailed Description of the Invention
The following description relates only to specific embodiments of the present invention
and is in no way intended to limit the scope of the present invention to those specific
embodiments. In particular, the following description is exemplary rather than limiting in
nature. Variations and modifications to the disclosed methods may become apparent to
those skilled in the art that do not necessarily depart from the essence of this invention.
The invention will now be described with reference mainly to a high loading suspension
formulation of Mancozeb, Diuron, Atrazine or Captan. It is anticipated that similar results
can be found for suspension formulations in oil of other solid active ingredients, which are
not soluble in the continuous phase.
A typical OD formulation would have a composition as described in Table 1 below:
Table 1. Typical Components required for an Oil Dispersion Formulation
EXAMPLES
All formulations were subject to accelerated storage at 54°C unless stated otherwise and
where possible, suspensibility measurements were conducted pre-storage at 2%w/v in
20ppm ambient water according to CIPAC MT161. Despite such testing not being an
official requirement of the FAO regarding OD formularies, in this instance residue
suspensibilities were determined to best characterise the quality of the oil/solid dispersion
when diluted.
OF and OD Formulations using Mancozeb as the active ingredient
Example 1 (Comparative)
Preparation of an OD formulation comprising a Bentone® anti-settling agent
The following formulation was prepared:
Mancozeb (85 w w Technical) 567 g L
TERSPERSE 2510 dispersant 70
SURF0NIC ® LF17 surfactant 15
SURF0NIC ® P3 surfactant 15
SURFONIC® TDA3B surfactant 10
TERSPERSE ® 2202 dispersant 5
Bentone® IPM 5
EXXSOL ®D130/HYDROSEAL ® G250H (50:50 blend) to Volume ( 1 Litre)
The formulation was made in the manner known to those skilled in the art by dissolving the
oil dispersant TERSPERSE ® 2510 dispersant in 90% of the oil phase and adding the
Mancozeb powder to it with high shear mixing to form a slurry which was then milled in a
bead mill to produce a millbase with the technical at an average particle size (do.s) of less than
5 microns (). To the millbase is then added the other surfactants and the Bentone ®
thickener with stirring.
The formulation was placed on storage at 54°C. While the initial emulsification of this
formulation was satisfactory, after less than 5 days the formulation, formed into a thick gel
with a hard packed sediment layer.
This formulation demonstrates that even relatively high amounts of the Bentone® thickener
are not able to prevent sedimentation and also afford a satisfactory viscosity for this product.
Example 2 (Comparative)
The following OF formulation was prepared:
Mancozeb (85%w/w Technical) 705.88 g L
TERSPERSE ® 2510 dispersant 67.5
HYDROSEAL ® G250H to Volume ( 1 Litre)
TERSPERSE ® 2510 dispersant is a polyalkylene glycol-fatty acid condensate where n is no
more than 34 units as per Structure (1).
The oil dispersant TERSPERSE ® 2510 dispersant is dissolved in 90% of the oil phase and the
Mancozeb powder is added to it with high shear mixing to form a slurry, which is men milled
in a bead mill to produce a millbase with the technical at an average particle size (do.5) of less
than 5 microns (). The final formulation is then made up to volume with further
HYDROSEAL ® G250H and the mixture was stirred until it was homogeneous.
The formulation was placed on storage at 54°C. The emulsification of this formulation was
not satisfactory and formulation was low in viscosity. After 7 days, the formulation showed
10% syneresis and a hard packed sediment layer which was non-redispersable.
This formulation demonstrates that TERSPERSE® 2510 dispersant is not able to prevent
sedimentation and also afford a satisfactory viscosity for this product.
Example 3
The following OD formulation was prepared:
Mancozeb (85%w/w Technical) 705.88 g/L
TERSPERSE® 2510 dispersant 60
DS 10486 40
HYDROSEAL® G250H to Volume ( 1 Litre)
DS 10486 is a monoblock butyl ether condensate with n + m being on average 40 units as
per Structure (1) and x is on average 5 units as per Structure (2).
The oil dispersant TERSPERSE ® 2510 dispersant and DS 10486 is dissolved in 90% of the
oil phase at 55°C until a clear homogeneous solution is obtained. After the oil mixture was
cooled to ambient temperature, the mancozeb powder is added with high shear mixing to form
a slurry, which is then milled in a bead mill to produce a millbase with the technical at an
average particle size (das) of less than 5 microns (). The final formulation is then made
up to volume with further HYDROSEAL ® G250H and the mixture was stirred until it was
homogeneous.
The formulation was placed on storage at 54°C. The emulsification of this formulation was
satisfactory. After 7 days, the formulation showed only 3.6% syneresis, no change in viscosity
and no hard packed sediment layer was observed.
This formulation demonstrates that a combination of TERSPERSE ® 2510 dispersant and DS
10486 is able to prevent sedimentation and affords a satisfactory viscosity and that DS 10486
is also able to function as an emulsifier.
Example 4
The following OD formulation was prepared:
Mancozeb (85%w/w Technical) 705.88 g L
TERSPERSE ® 2510 dispersant 38.75
DS 10485 38.75
TERMUL 3665 emulsifier 90
HYDROSEAL ® G250H to Volume (1 Litre)
DS 10485 is a diblock condensate with n + m being on average 90 units as per Structure
(1) and x is on average 2.6 units as per Structure (2).
The oil dispersant TERSPERSE ® 2510 dispersant and DS 10485 is dissolved in 90% of the
oil phase at 55°C until a clear homogeneous solution is obtained. After the oil mixture was
cooled to ambient temperature, the Mancozeb powder is added with overhead mixing to form
a slurry. The Mancozeb pre-mix is transferred to a bead mill and milling is continued until
an average particle size (do.s) of less than 5 microns () is obtained. The TERMUL ® 3665
emulsifier was added to the milled pre-mix under high shear. The final formulation is then
made up to volume with further HYDROSEAL ® G250H and the mixture was stirred until it
was homogeneous.
The formulation was placed on storage at 54°C and 20°C and after 14 days no hard pack
layer or flocculation was observed and the formulation only displayed a trace of syneresis
(<1%). The formulation showed excellent emulsification on dilution with water. The
residue suspensibility of the formulation was measured using CIPAC MT 161
(suspensibility of suspension concentrate formulations) and found to be 99%.
Example 5
The following OD formulation was prepared as per the method described in Example 4:
Mancozeb (85%w/w Technical) 705.88 g L
TERSPERSE ® 2510 dispersant 60
DS 10486 40
TERMUL ® 3665 emulsifier 70
HYDROSEAL ® G250H to Volume ( 1 Litre)
The fonnulation was placed on storage at 54°C and 20°C and after 14 days and no hard
pack layer or flocculation was observed. The formulation showed a trace of syneresis
(<1 ). The formulation showed average bloom and excellent emulsification on dilution
with water. The residue suspensibility of the formulation was measured using CDPACMT
161 (suspensibility of suspension concentrate formulations) and found to be 99%.
Example 6
The following formulation was prepared as an additive which may further assist the
structuring effect of polyalkylene glycol fatty acid condensates:
KRATON® G-1701 15.00%w/w
SOLVESSO® 200 85.00
KRATON® G-1701 polymer is described as a polymer of styrene and
polyethylene/polypropylene as a diblock.
SOLVESSO® 200 is an aromatic solvent available from Exxon-Mobil.
To an appropriate vessel, the required amount of SOLVESSO® 200 and KRATON® G-
1701 are added. The resultant mixture is then heated with moderate stirring until such point
that a gelatinous, yet flowable, homogeneous consistency is observed. On cooling, the
viscosity increases further forming a workable gel, which is stored for later use.
Example 7
The following formulation was prepared:
. Mancozeb (85%w/w Technical) 705.88 g 1
TERSPERSE ® 2510 40.00
DS 10486 33.33
DS 10541 16.67
TERMUL ® 3665 70.00
Structuring blend from Example 6 comprising KRATON® G-
1701 and SOLVESSO® 200 40.00
HYDROSEAL® G250H to Volume (1 litre)
DS 10541 is a monoblock butyl ether condensate with n + being on average 120 units as
per Structure (1) and x is on average 5 units as per Structure (2).
To an appropriately sized beaker, 333.12g/L of HYDROSEAL® G250H was added,
followed by the required amounts of TERSPERSE® 2510, DS 10486, DS 10541 and
TERMUL® 3665. The mixture was then subject to moderate heating (approx. 30-40° C) for
several minutes, then exposed to high shear mixing to form a homogeneous pre-dispersion.
Once cooled to ambient temperature, the required amount of Mancozeb (85%w/w
technical) was dispersed followed gradual addition of structuring blend from Example 6
comprising RATO ® G-1701 and SOLVESSO® 200. The resultant mixture was then
subject to further high shear until satisfied that a homogeneous clump-free dispersion was
achieved.
The formulation initially appears as a homogeneous yellow dispersion of intermediate
viscosity. After storage for 14 days at 54° C, the formulation displayed 6.6% syneresis in
addition to a slight increase in viscosity, however remained flowable with only the
presence of minor re-dispersible soft packing.
OP Formulations using Diuron 400g/L as the active ingredient
Example 8 (Comparative')
The following formulation was prepared:
Diuron (95%w/w Technical) 421.05 g 1
TERSPERSE® 2510 40.00
TERIC® 12A3N 100.00
TERMUL® 3665 15.00
Rheology Modifier
EXXSOL® Dl 30 to Volume ( 1 litre)
To an appropriately sized beaker, approximately 150g L EXXSOL® D130 was added,
followed by the required amounts of TERSPERSE® 2510, TERIC® 12A3N and
TERMUL® 3665. The mixture was then subject to moderate heating (approx. 30-40° C) for
several minutes, then exposed to high shear mixing to form a homogeneous pre-dispersion.
Once cooled to ambient temperature, the required amount of un-milled Diuron (95%w/w
Technical) was dispersed and high shear mixing was continued for several minutes. The
formulation was then allowed to settle, made to the required volume with further
EXXSOL® D130 (if necessary), and returned to shear until homogeneous.
The formulation initially appears as a homogeneous white dispersion of relative low
viscosity, that when diluted in 20ppm ambient water emulsifies readily. Of note is the
development of syneresis within several minutes. Following storage for 14 days at 54° C,
it was observed that the above formulation had developed 55% syneresis in association
with the presence of a permeable yet somewhat rigid gel-like matrix which upon stirring
proved difficult to fluidise.
The formulation demonstrates relatively less than optimum stability afforded by a lack of
suitable rheology modifier.
Example 9
The following formulation was prepared according to the method outlined in Example 8 :
Diuron (98%w/w Technical) 408.16 g 1
TERSPERSE® 2510 48.00
HCA00103/132 12.00
TERIC® 12A3N 100.00
TERMUL® 3665 15.00
Structuring blend from Example 6 comprising KRATON®
G-1701, SOLVESSO® 200 97.52
EXXSOL® D130 to Volume ( 1 litre)
HCA00103/132 is a 1:1 blend of a diblock condensate with n + m being on average 45
units as per Structure (1) and x is on average 5 units as per Structure (2) and a diblock
condensate with n + m being on average 90 units as per Structure (1) and x is on average 5
units as per Structure (2).
The formulation initially appears as a homogeneous white dispersion of a relative
intermediate to high viscosity, that when diluted in ambient 20ppm water emulsifies
readily to yield a residue suspensibility of 77% after 30 minutes. Following storage for 7
days at 54°C, the formulation showed an increase in viscosity however remained
homogeneous and retained flowability. Of importance was the notable suppression of
syneresis, which was measured at 8.8%. At room temperature following the same period,
the formulation remained flowable and homogeneous with trace syneresis.
The formulation demonstrates the improved effect of using an alternate fatty acid-alkylene
glycol in combination with KRATON® G-1701.
O Formulations using Atrazine 40Qg/L as the active ingredient
Example 10 (Comparative)
The following formulation was prepared according to the method outlined in Example 3:
Atrazine 400.00 g
TERSPERSE® 2510 40
TERIC® 12A3N 100
TERMUL® 3665 15.00
EXXSOL® D130 to Volume ( 1 litre)
The formulation initially appears as a homogeneous white dispersion of a relative
intermediate viscosity which gives suitable emulsification performance in 20ppm ambient
water. Following storage for 14 days at 54°C, the formulation displayed 48% syneresis
with the bulk consisting of a homogeneous easily permeable gel-like structure that through
stirring was reversible to a flowable consistency similar to its pre-storage appearance.
Atrazine 400g/L comprising polvalkylene glvcol-fatty acid condensates
Example 11
The following formulation was prepared according to the method outlined in Example 3:
400.00 g l
48.00
12.00
100.00
15.00
Structuring blend from Example 6 comprising KRATON G-1701 60.00
and SOLVESSCT 200
EXXSOL® D130 to Volume (1 litre)
The formulation initially appears as a homogeneous white dispersion of a relative
intermediate viscosity which gives suitable emulsification performance in 20ppm ambient
water. Following storage for 7 days at 54°C, the formulation displayed 14.0 % syneresis
with the bulk remaining flowable, homogeneous and free of any packing or caking. After
the same time period at ambient temperature, the formulation maintains flowability with
only a trace of syneresis.
Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this
specification, they are to be interpreted as specifying the presence of the stated features,
integers, steps or components referred to, but not to preclude the presence or addition of
one or more other feature, integer, step, component or group thereof.
CLAIMS
What is claimed is:
1. An agricultural oil-based suspension formulation comprising an active ingredient
suspended in finely divided form in an oil; and at least one surfactant selected from a
polyalkylene glycol-fatty acid condensate or a polyalkylene glycolether fatty acid
condensate formed from a reaction between a compound having Structure (1) and a
compound having Structure (2):
R - (OA)n—(OB)m-OH + HO R¾ --C -- 0-i Hx
(1) (2)
wherein =H or a C1-C30 alkyl radical;
A and B are ethylene or propylene groups in succession or random;
n = 0 or>l; and
m=0 or>l,
and wherein n+m > 34;
R = C8-C30 alkyl or alkylene radical (branched or linear); and
x = >l.
2. An agricultural oil-based suspension formulation according to Claim 1, wherein the
surfactant comprises a diblock condensate of polyethylene glycol having a molecular
weight greater than 1500amu and a polyhydroxystearic acid copolymer of
condensation range greater than 2 units.
3. An agricultural oil-based suspension formulation according to Claim 1, wherein the
surfactant comprises at least one monoblock condensate of a polyalkylene glycol
ether-fatty acid condensate, wherein the polyalkylene glycol ether is an ethylene
oxide-propylene oxide copolymer butyl ether having a molecular weight of greater
than 1800amu and the fatty acid condensate is a polyhydroxystearic acid copolymer
of condensation range greater than 2 units.
4. An agricultural oil-based suspension formulation according to Claim 1, wherein the
formulation is selected from an Oil Dispersion ("OD") or an Oil-miscible Flowable
("OF') formulation.
5. An agricultural oil-based suspension formulation according to Claim 4, wherein the
OD formulation further comprises an emulsifying agent and/or a rubber-type
copolymer as an additional anti-settling agent.
6. An agricultural oil-based suspension formulation according to Claim 1, wherein the
active ingredient is selected from Mancozeb, Diuron, Atrazine and Captan, or
mixtures thereof.
7. An agricultural oil-based suspension formulation according to Claim 6, wherein the
active ingredient is Mancozeb.
8. An agricultural oil-based suspension according to Claim 7, wherein the Mancozeb is
present in a concentration greater than 400g/L.
9. An agricultural oil-based suspension formulation according to Claim 8, wherein the
Mancozeb is present in a concentration greater than 580g/L.
10. A method of application of the agricultural oil-based suspension formulation
according to Claim 1, having a rate of use of polyalkylene glycol-fatty acid
condensate or polyalkylene glycolether fatty acid condensate in a range of from 2-
10% w/v in the formulation.
11. A method of application according to Claim 10, wherein the rate of use is in the
range of 3-8% w/v in the formulation.
12. The method according to Claim 10, wherein the active ingredient is selected from
Mancozeb, Diuron, Atrazine and Captan, or mixtures thereof.
13. The method according to Claim 12, wherein the active ingredient is Mancozeb.
14. The method according to Claim 13, wherein the Mancozeb is present in a
concentration greater than 400g L.
15. The method according to Claim 14, wherein Mancozeb is present in a concentration
greater than 580g/L.
16. A method of preparing an OD formulation comprising an active ingredient
V
comprising the steps of:
a) preparing a surfactant solution premix by combining at least one surfactant
selected from a polyalkylene glycol-fatty acid condensate or a polyalkylene
glycolether fatty acid condensate of the present invention with a surfactant and
an oil to give a liquid;
b) dispersing the active ingredient in the surfactant solution by either stirring or
high shear mixing;
c) milling the active ingredient dispersion to achieve a particle size average in the
range 1-12 microns;
d) adding surfactant emulsifying agents; and
e) optionally adjusting the final concentration of active ingredient content by
adding additional oil and other required ingredients,
wherein steps a) to d) are carried out in any order.
17. The method according to Claim 16, wherein step (e) includes adding a rubber-type
copolymer as an additional anti-settling agent.
18. The method according to Claim 17, wherein the active ingredient is selected from
Mancozeb, Diuron, Atrazine or Captan, or mixtures thereof.
The method according to Claim 18, wherein the active ingredient is Mancozeb.
20. The method according to Claim 19, wherein the Mancozeb is present in a
concentration greater than 400g/L.