Note: Descriptions are shown in the official language in which they were submitted.
13~19~
BACKGROUND OF THE INVENTION
Field of the Invention ~- -
The present invention relates to a superabsorbent
polymer herbidical delivery agent having excellent formulation
flexibility, controlled release potential, run-off resistance and
hydrodynamic properties.
Description of the Prior Art
Infestations of aquatic and wetland plants (weeds) such
as hydrilla, southern water-grass, waterhyacinth, watermilfoil,
Salvinia, etc., have caused detrimental effects on health, ~ ~ ;
agriculture, commerce, and recreation in many arPas of the United
States and overseas. When present in high densities, these weeds ~ ;
can literally choke lakes and rivers, thereby preventing access
by boats and barges. In addition, these weeds can disrupt the
~unctioning of drainaye, irrigation, flood control and water
conservation pro-Jects and hydroelectric power plants, provide
breeding grounds for disease carrying mosquitoes and snails,
eliminate fishing in certain areas, and alter aquatic ecosystems
by preventing sunlight from reaching other plants and animals
which live beneath these vegetative mats. Therefore, the growth
of these nuisance plant papulations must be controlled.
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Aquatic and wetland weeds can be controlled by heavy
machines (mechanical control) by a variety of insects, pathogens,
- and other organisms (biological control) by drawdowns, plastic
-~
sheets, and colored dyes (cultural control), and, most commonly, - ~ ~
by the use of chemical herbicides (chemical control). The - - ;
concurrent or sequential use of t~o or more of these control
procedures is referred to as integrated control. Solid and ~ ~ ;
liquid herbicide fonmulations designed for quick and slow or
controlled release of the active ingredients are currently in use
to control aquatic and wetland plants; however, new ~ormulations
are needed that can enhance the e~ficacy and/or extend the range -~
of performance of e~isting products.
U.S. Patent Nos. 4,400,391 and 4,401,456 disclose the
use o~ alginate gel beads to encapsulate bioactive materials to
provide ~or their controlled release. The patents describe beads ~ -
being made to either float or sink (i~ used in an aqueous
environ~ent) and they may contain herbicides. These beads are
also described as acting as carriers to place the bioactive
material near the target species, for example, a floating bead
containing a herbicide,releasing the herbicide in close proximity
to ~loating aquatic weeds, or the beads falling through foliage
to release herbicide into the soil. U.S. Patent No. ~,3~,857
involves enaapsulatlon of xanthate derivatives. The
encapsulation techniques are complicated, costly and quality
.. ,~ ~ , ... .
sensitive.
' A relatively new approach to herbicide delivery has
been by application of controlled release formulation such as
described by Richard W. Baker in Controlled Release of
Biologically Active Aqents, 1987, Wiley-Interscience Publishing,
' 279 pp. ~his book describes the use o~ various controlled
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release technologies including simple diffusion from monolithic
devices such as hydrogels. More complex release mechanisms
include the use of biodegradable matrix carriers, bonding of
active ingredients in heterogeneously or homogeneously degradable -`~
polymers, called polyagents. Polyagents may actually be polymers
formed of monomers of the active agent. The release mechanics of
these controlled release mechanisms are complex depending on the
presence (and strength3 or absence, of degradable ligand bonds `~
and their location of the degradable bonds (e.g., as active agent
bonds to the polymer), the concentration of the active agent
and/or dispersant or solvent in the carrier, the relative
hydrophobicity or hydrophilicity of the polymer, whether or not
the polymer degrades homogeneously or heterogeneously, whether
the active agent is in the solid form or the liquid form in the
polymer, etc.
A relatively new class of polymers has recently been
introduced that exhibits remarkable absorbency. However, there
has been no recognition of their uses for herbicide delivery.
One example is the acrylic-based superabsorbent polymers. The
aqueous absorbency mechanism of acrylic-based superabsorbent
polymers has been described by the Chemdal Corporation (Arlington
Heights, Illinois 60004) in their Technical Data Sheets on
Aridall~ Superabsorbent Polymers. The absorbency of acrylic-
based superabsorbent polymers ls attributed to the carboxylic
groups located on the backbone of the superabsorbant polymer.
When water contacts the superabsorbent polymer, these groups
solvate rapidly and develop mutually repulsive negative charges.
This causes the superabsorbent polymer to uncoil and absorb many
times its weight in water. Crosslinking prevents solution of the
superabsorbent polymer. The aqueous medium rapidly becomes
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oriented on the surface of the superabsorbent polymer by virtue
of hydrogen bonding. The resulting gel has remarkable ability to
hold the aqueous medium even under pressure. Superabsorbent
polymers hold fluids by a physico-chemical mechanism.
Electrolytes/salts interfere somewhat with the hydrogen bonding.
Crosslinked aarylic-based superabsorbent polymers always absorb -~
less aqueous medium when electrolytes/salts are present.
Specific Obi~ts
It i5 therefore an object of the present invention to
provide compositions that are solid or flowable, and methods for
the dry, moist, semi-aquatic, or aquatic ground or aerial
treatment of a variety of aquatic plant (weed) habitats with the
composition (5), which overcomes the prcblems and deficiencies o~ the
prior art. -
It is also an object of the present invention to
provide a composition and method, which is easy to prepare
~(formulate) and use (apply), and which is biodegradable and safe
to th~ environment, but which is effective for use in controlling
one or more immature and mature stages of obnoxious or
undesirable aquatic and wetland weeds or related vegetation.
It is a further object of the present invention to
provide an agglomerated or non-agglomerated solid or variable~
viscosity, ~lowable (aqueous-or oil-base) composition and method
which can incorporate a wide variety of herbicidal, or
herbicidal/pesticidal ingredients into a single, stable and
homogeneous herbicidal delivery system to control a broad
spectrum of aquatic and wetland plant populations and other
related habitat pests, and to provide for the variable time-
release of the active ingredients. ~ ;
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1331924 ; ~
Still another object of the present invention is to -
provide a method for simultaneously or concurrently controlling
two or more natural populations of aquatic and wetland
vegetation, and habitat-related pests such as mosquitos and
snails with a single, variable-density and/or variable-viscosity
herbicidal/pesticidal superabsorbent polymer carrier or matrix
delivery formulation.
Still another specific object of the present invention
is the provision of incorporating one or more surfactant(s),
oil(s), surface-active agent(s) or film-forming agent(s) into a
stable and homogeneous, variable-viscosity, flowable herbicidal
superabsorbent polymer(s) formulation, the addition of which can ;~
slow the rate of release of one or more active ingredients in the -~
herbicidal delivery composition.
Still another object of the present inventinn is to
provide a method for simultaneously or concurrently controlling
natural populatlons of aquatia and wetland plants and habitat-
related pests that allows for broadcast coverage with a variety
o~ solid or ~lowable superabsorbent polymer formulations with
conventional application methods without significant losses to
wind dri~t, whlle enhancing canopy penetration or target
substrate adherence.
These and other ob;ects are accomplished by the
compositions and method of the present invention.
SummarY of the Invention
The present invention relates to a solid or variable-
viscosity,flowable (i.e., sprayable, pumpable, injectable)
herbicidal delivery composition made from one or more solid
superabsorbent polymers with or without water, and with one or
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133i924
more liquid and/or solid herbicides, desiccants, algicides,
defoliants, hormones, plant growth regulators, plant growth
inhi~itors, petroleum oils or solvents, sterilants, biological
control agents, microbial control agents, pathogens, or
parasites, with or without one or more pesticidal agents, such as :
insecticides, mosquitocides, schistomacides, molluscicides,
ovicides, larvicides, monomolecular films, duplex films,
monolayers, petroleum oils, pupicides, biological control agents,
pathogens, parasites, microbial control agents, insect growth
regulators, convention~l toxicants, pesticides, chemosterilants,
surface-active agents or film-forming agents, with or without one ~::
or more nontoxic adjuvants or diluents such as carriers, binders, .~
daflocculating agents, dispersing agents, penetrants, spreading : -:
agents, surface-active agents, surfactants, suspending a~ents, : -~ :~
wetting agents, stab.tlizing agents, compatability agents, ;
sticking agents, waxes, oils, inverting oils, co-solvents,
coupling agents, foams, antifoaming agents, synthetic plastics, :~
elastom~rs, synergists, natural or synthetic polymers; and other
additive3 and mixtures thereof.
The present invention also relates to a facile method
of applying the solid or flowable, aqueous-or oil-base,
herbicidal delivery composition with one or more active
ingredients, with or without one or more pesticidal and/or
nonpesticidal ingredients, to control a variety of aquatic and
wetland plants or related vegetation in dry, moist, semi-aquatic,
or aquatic environmentts) with conventional ground or aerial
techniques.
This invention further relates to a facile method of
combining, mixing, encapsulating, agglomerating, or formulating :~
two ingredients, optionally with water or oil, or one or more ~ :
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1331~2~
pesticidal agent(s) and/or various nontoxic adjuvants, diluents
or carriers, etc., with one or more superabsorbent polymers into
solid powders, dusts, granules, pellets, or briquets, and/or into
flowable,variable-viscosity formulations such as sols or semi-
gels. The use of superabsorbent polymers in this manner makes
possible the mixing or application of herbicidal ingredients with
or without additional pesticidal ingredients or other additives ;~
that would otherwise be difficult or substantially impossible to
combine as joint-or multiple-action solid or flowable (aqueous or
oil-base) formulations.
In particular, the present invention is directed toward
a method of formulating one or more superabsorbent polymer~s)
with one or more herbicidal agent(s), with or without water or
one or more pestiaidal agents or other additives, into solid
powders, dusts, granules, pellets or briquets, or into flowable,
variable-viscosity sol or semigel-like preemergence or
postemergence formulations that can produce quick, slow,
controlled, prolonged, or extended release of one or more active
lngredients to simultaneously or concurrently control a variety
of aquatic and wetland plants such as plankton algae, filamentous
algae, submersed weeds, emersed weeds, marginal weeds and
floating weeds, while simultaneously or concurrently controlling
a variety of other pests such as mosquitoes and snails in dry,
moist, semi-aquatia, or aquatic habitats with a single
application of a solid or ~lowable multi product formulation.
.. ,.;
Se~cific AsPects ~
In accordance with one aspeat of the present invention, ~;
there is provided an agglomerated or non-agglomerated, solid or
variable-visco~ity, flowable (aqueous-or oil-base) herbicidal
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~331924 ~
preemergence or postemergence delivery composition for ~ ~
controlling populations of aquatic and wetland weeds (plants) or -
related vegetation, the delivery composition being applied by
ground or aerial techniques ~i.e., by aircraft, boats, trucks,
etc.) to a variety of dry, moist, semi-aquatic or aquatic
habitats. The compositions include at least one superabsorbent .
polymer, and at least one herbicidal agent, alone or in
combination with water, adjuvant(s), diluent(s), or carrier ~.
agent(s), or other additive(s), the superabsorbent polymer(s) and
herblcidal agent(s) baing present in a total amount e~fective to
control the population of aquatic and wetland plants or related
vegetation. The diluent(s), adjuvants(s), carrier agent(s), or .
other additive(s), if present, is at a concentration adapted to ~
improve formulation component mixing, compatability, and/or :
stability and/or to allow proper impregnation or mixing of the :~
herbicidal agent(s) on, and/or in, ~he superabsorbent
polymer(s). Preemergence or postemergence herbicidal agents are
selected from solid and/or liquid desiccants, herbicides, ;~
algiaides, petroleum or non-petroleum oils, dePoliants, hormones,
plant growth regulators, plant growth inhibitors, biological
control agents, microbial control agents, pathogens, parasi.tes,
and mixtures thereof. .
In accordance with another aspect of the present
invention, there is provided a solid or flowable, preemergence or
postemergence, variable time-release herbicidal delivery
composition for controlling a population of aquatic and wetland :; ; .:.
weeds or related plants which includes one or more superabsorbent
polymer(s) and mixtures thereof, at least one herbicidal agent and
at least one herbicidal adjuvant, carrier or diluent, the
superabsorbent polymer, herbicidal agent(s), and adjuvant(s),
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carrier(s) or diluent(s) being present in a total amount
effective to control the population of aquatic and wetland plants
or related vegetation, the variable time-release delivery
composition being applied as a ground or aerial treatment to the
aquatic and wetland habitat. Carrier, adjuvant, or diluent
materials are selected from water, surfactants, alcohols, film-
forming agents, surface-active agents, petroleum-or vegetable-
base oils, etc., and mixtures thereof, the carrier, adjuvant, or
diluent being present at a concentration re~uired to slow,
control or vary the rate of release or active components in the -~
solid or flowable, superabsorbent polymer composition.
In accordance with yet another aspect of the present
invention, there is provided a solid or flowable, variable time-
release herbicidal delivery composition for controlling a
population of aquatic and wetland environment plants. The
composition includes at least one superabsorbent polymer, at
least one herbiaidal agent, and at least one additional ~;
pesticidal agent, with or without water or additional nontoxic
ad~uvants, diluents, or other additives. Diluent, adjuvants, or
other additive ingredients are selected from surfactants,
surface-active agents, ~ilm-forming agents,
petroleum oils, vegetable oils, suspending agents,
wetting agents, penetrants, spreading agents, stabilizing agents, ;~
compatability agents, sticking agents, carriers, binders, co~
solvents, coupling agents, deflocculating agents, dispersing
agents, waxes, oils, synthetic plastics, foams, anti-foaming
agents, synergists, elastomers, natural or synthetic polymers,
and other additives and mixtures thereof. The superabsorbent
polymer~s), herbicidal agent(s), and additional pesticidal
agent~s) and adjuvant(s) or diluent(s) are present in a total
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1331924
amount effective to simultaneously or concurrently control the : : :
population of aquatic and wetland plants and habitat-related ~ :
pests, the variable time-release delivery composition being
applied as a preemergence or postemergence formulation by ground
or aerial treatMent to the aquatic and wetland habitat.
In accordance with another aspect of the present
invention, there is provided a method for controlling a - :
population of aquatic and wetland environment plants (weeds) or
related vegetation which includes the steps of: :
preparing or formulating an agglomerated or non~
agglomerated, solid or flowable,herbicidal delivery composition
which includes at least one superabsorbent polymer and at least
one herbicidal agent, with or without water or additional
nontoxic adjuvants, diluents, carriers or other additives, by a
series of soakings, washes, variable-speed blendings or simple ;~
mixlng, salt/electrolyte conditioning treatments or reactions,
and/or temperature and/or moisture conditioning treatments or
,~ - . .
reactions;
applying said herbicidal delivery composition in an :~
amount effective to control a population of aquatic and wetland .
plants or related vegetation, the delivery composition being ;
applied by ground or aerial treatment to the aquatic and wetland
habitat.
In accordance with still another aspect of the present
invention, thers is provided a method for simultaneously or
concurrently controlling a population of aquatic and wetland .
plants and related vegetation and habitat-related pests, e.g.,
mosquitoes and snails. The method includes the steps of~
¦ preparing or formulating an agglomerated or non-
agglomerated solid or flowable, variable viscosity, ~;
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~331924
herbicidal/pesticidal delivery composition which includes at
least one superabsorbent polymer, at least one herbicidal agent
with or without water, and with at least one additional
pesticidal agent and/or nontoxic diluent, adjuvant, carrier, or
additive agent by a series of soakings, washes, variable-speed
blending, salt/electrolyte conditioning treatments or reactions,
and/or temperature and moisture conditioning treatments or -~
reactions. Additional pesticidal agents are selected from film-
forming agents; monolayers; monomolecular surface ~ilms; duplex
films; surfactants; surface~active agents; petroleum and non-
petroleum oils; mosquitocides; schistomacides; molluscicides;
ovieides; larvicides; pupicides; insecticides; conventional
toxicants; pestieides; chemosterilants; biological con-trol
agents; microbial control agen-ts; p~thogens; parasites;
insect growth regulators; and mixtures thereof; and
applying said herbieidal/pestieidal delivery
eomposition in an amount efPeetive to simultaneously control a
population o~ aquatie and wetland environment plants and habitat-
related pests (e.g., mosquitoes and snails), with the delivery
~¦ eomposition being applied by ground or aerial treatment to the
aquatie and wetland habitat. ,~
The use of superabsorbent polymer(s) of the present
invention provides simple and easy techniques for the
incorporation or encapsulation of a variety of herbicidal and
herbieidal/pestieidal ingredients into agglomerated or non-
agglomerated solid earrier matrices, e.g., dense pellets,
granules, or briquets, ~or the slow or eontrolled release of
aetive agents in a variety o~ aquatie and wetland habitats.
Agglomerated or non-agglomerated superabsorbent polymer
formulations of the present invention containing one or more
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1331924
, . - ,
diluent or adjuvant surfactant(s), oil(s), surface-active -
agent(s) or film-~orming a~ent(s), can effect a mechanism for
reducin~ the rate of water absorption (hence superabsorbent
polymer swelling), and thereby slow down the rate of release o~
one or more active agent(s) from the solid matrice~, and extend
the field life or persistence o~ the active agent(s) ~or a period
of time greater than would be e~pected with superabsorbent
polymer formulation~ containing no ~urfactant(s), film-forming
agent(s), surface-active agent(s), or oil(s). Similarly, certain
of the flowable, variable-viscosity superabsorbent polymer
compositions ~f the present invention, which are formulated with
water and/or one or more ~urfactant(s), oil(s), surPace-active -~
agent(s), or film-forming agent(s), can slow or control the
release rate ef the a¢tive formulation ingredients, while
enhancing target sub~trate adherence and minimizing wind drift
1088.
~ he ~olid or flowable composition~ of superabsorbent
polymer~3) will also be suitable with various preemergence
herbicidal agent~s), with or without additional pe~tiaidal
agent(~) or other additive(~) which can be directly incorporated
on, and/or lnto, dry or moist soil by variou~ techniques (e.g.,
soil in~ection). The superabsorbent polymer oarrier/diluent/
encapsulation matrix facilitates resistance to surface/subsurface
run-off or percolation losses of the active agent~. Varied
application~ from broadcast to point-specific, controlled-release
applications against a variety of aquatic weeds can be
accomplished by ad~u~ting the agglomeration or formulatlon
process, and~or the specific gravity of the carrier/matrix, and
,thereby produce formulations that can float and/or 6ink, or
provide broadcast or point-epecific coverage for controlled,
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1331g24
quick or long-term release. For example, when a dense pellet is
employed, the resulting sinking formulation can be evenly
distributed over an aquatic envirom~lent without herbicidal loss
or redistribution problems due to run-off or wind fetch. In
addition, variable-viscosity, sprayable, pumpable, or injectable
formulations of superabsorbent polymer(s) and one or more
surfactant(s), oil(s), surface-active agent(s~ or film-forming
agent(s), formulated with or without water, can eff~ct a simllar
mechanism for variable time-release (i.e., slow or controlled
release) of active ingredients in floating and/or sinking
compositions, thereby extending the field life or persistance o~
the herbicide(s), with or without additional pesticidal ;~
¦ additives, for a greater period of time than would be expected
¦ with superabsorbent polymer formulations containing no
surfactant~s), oil~s), surface-active agent(s) or, film-forming
agent~). This can extend the field persistence of the active ` ` `
agent(s) in the flowable superabsorbent polymer formulation, and
thereby assure thak the ~requency of costly herbicidal
retreatmsnts per habitat will be reduced.
;' The superabsorbent polymers of the present invention
j are synthetic organic polymers, which are solid and hydrophilic,
absorbing over lOO times their weight in water. Generally, these
superabsorbent polymers are chosen from acrylamide and acrylate
polymers, co-polymers and ter-polymers which are optionally
crosslinked or starch grafted acrylonitriles, acrylamide and
acrylate polymers, co-polymers and ter-polymers. These
superabsorbent polymers are typically in a powder, crystal, or
flake form, adapted to be blended and/or agglomerated.
The superahsorbent polymers may be, for example,
acrylamide alkali metal or alkali metal/aluminum acrylate co~
:: ., ',, -', '~ -
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polymers; propenenitrile homo-polymers, hydrolyzed alkali metal
or alkali metal/aluminum salts; polymers of propenamide and
propenoic acid, alkali metal or alkali metal/aluminum salts;
hydrolyzed acrylonitrile co-polymers and starch graft co-polymers
and ter-polymars thereof. All of these are designed to be
extremely hydrophilic, absorblng over 100 times their weight in
water. ~.
The solid or flowable superabsorbent polymer
formulations of the present invention may be composed of one or
.
more of a wide choice of solid and/or liquid herbicidal agents,
such as herbicides, algicides, desiccants, defoliants, hormones,
plant growth regulators, plant growth inhibitors, petroleum oils ` :~
or solvents, biological control agents, microbial control agents, ::~
pathogens, or parasites, with or without additional pesticidal ~----
agent ingredients, such as inseaticides, mosquitocides, :~ :
.
- -.
schistomacides, molluscicides, insect growth regulators,
conventional toxicants, pesticides, chemosterilants, film~
Porming agents, monolayers, duplex films, monomolecular surface `~
films, or petroleum oils, and with or without nontoxic agents
such as water, surfaatants, spreading agents, adjuvants, : :
carriers, binders, deflocculating agents, dispersing agents,
synergists, penetrants, suspending agents, surface active agents,
film-forming agents, sticking agents, wetting agents, stabilizing
agents, compatability agents, co-solvents, coupling agents,
foams, anti-foaming agents, diluents, waxes, oils, synthetic
plastics, elastomers, inverting oils, natural or artificial
polymers and other additives and mixtures thereof; depending on
the type or nature of the aquatic and wetland habitat to be ..
controlled, the environmental impaat, and/or the plant
developmental stage and/or associated insect or pest species to ~ ~
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~ 33~924
be controlled. The solid or flowable formulations of the present
invention are biodegradable. They are also storage stable when
formulated, basically as stable as the individual components;
however, increased stability may occur in solid matrix form over
the flowable form. Solid or flowable superabsorbent polymer
formulations of the present invention can take a wide variety of
shapes, forms, and consistencies which may be required for a ;~
particular applicationc The solid or flowable superabsorbent
polymer formulations of the present invention can have a variable
time-release, either quick, or gradual as the situation requires.
The present invention provides a superabsorbent polymer carrier,
suspending, compatability, formulating or encapsulation agent for ~ -
the variable time-release or delivery of joint-or multiple-active
formulations of liquid and/or solid herbicidal and pesticidal
agents that would otherwise be difficult or impossible to combine
or mix as technical, oil-, or water-base products into a
homogeneous solid or flowable formulation.
Solid or flowable,herbicidal superabsorbent polymer
formulations of the present invention can be used to control
preemergence or postemergence aquatic and wetland weeds or
related vegetation ln areas that are dry, moist, semi-aquatic or
aquatic. Solid or flowable,herbicidal superabsorbent polymer
formulations of the present invention can also be combined with
additional pesticides to simultaneously or concurrently control
aquatic and wetlands plants and habitat-related pests such as
mosquitoes and snails in a variety of dry (pretreatment/-
preemergence), moist, semi-aquatic, or aquatic habitats. The
solid water-activated compositions have the ability to revert
back to a dry state form and return to a wet release form and
back again, depending on the habitat and/or climatological
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1331924
temperature/moisture conditions. This ability to transform from
a water-active, hydrodynamic release ~orm to an encapsulated dry -
or moist, inactive, semi-active, or static form, and back again,
can help protect the active agents from environmental
degradation. ~hi~ is a distinct advantage of the inætant
invention. This transformation/retransformation ability can also
be found in the flowable ~o1~po~itions; however, to a lesser
degree.
compaction or agglomeration of the superabsorbent
pol~mer matrix of the present invention has been shown to effect
a slow or controlled release mechanism for certain active
ingredient~. Generally, compaction or agglomeration will occur
subsequent to mixing/ble~ding with the active agents and various
ad~uvants. However, water soluble active agents and emulsions
can be di~fuaed to the ma~rix prlor to or subsequent to
agglomeration, and then reagglomeratad or compacted if desired.
In addition, varying tha ratio of different types of
the superabsorbent polymer~ used in the present invention, that
have di~erential water uptake or swelling characteristics or
~peaific gravitie~ ~e.g., Super Sorb, Aqua Kee ~ Water Loc ~,
Aridall~, and Aquastor ~ products) in a single compacted or
agglomerated matrix may e~ect a mechanism to further enhance the
controlled release of the active herbicidal or
herbicidal/pe~ticidal ingredients. Furthermore, the addition of
ad~uvants, carriers, or diluents such as film-forming agents,
surface-active agent~, oils, or surfactants to the herbiaidal or
herbicidal/pe~ticidal formulation can further provide a mechanism
to control (i.e., 310w) the rate of release of the active
ingredient~. Specifia gravity differences ~i.e., less than or
greater than one) o~ the superabsorbent polymers and/or additive
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1331924
. ~ ~.
active or inert ingredients of the present invention can be -
readily exploited to develop floating and/or sinking formulations ~ -
for use in a variety o~ hahitats to kill a variety of aquatic and - -
wetland plants (weedsj or related vegetation, and habitat-related -
pests.
~ Other ob~ects, aspects and advantages of the present
¦ invention will be apparent to ons of ordinary skill in the art
from the following: ~
ESCRIPTION OF THE PREFERRED EMBODIMENTS ~ ~ -
Surprisingly,it has been found that certain
superabsorbent polymers constitute a novel class of chemicals
useful as herbicidal delivery compositions ~or controlling
populations of aquatic and wetland plants or related vegetation
in an environment area needing aquatic and wetland plant control
treatment.
A herbicidal delivery composition is any composition
which can carry, or be adapted to carry, herbicidal agent(s) or ~
herbiaidal and pestiaidal agent(s), to the target habitat, ; ;;
natural or arti~i¢ial, aquatic, semi-aquatic, moist, or ~
dr~v. The herbicidal delivery agent matrix for incorporation into -
solld or flowable compositions is ~roadly one or more ,~i...... i.,".,",~
superabsorbent polymer(s). Superabsorbent polymers as a distinct ; ``
class o~ polymers, e.g., starch qraft co polymers, are known in
the art. See, for example, those described in United States ~ -
Patents Nos. 4,375,535 and 4,497,930 which are ~ ~ `
i disclosed as useful as adhesives, flocculan-ks,
¦ sizes, water-retaining materials Eor agriculture
~ (e.g., soil conditioners) and water-absorbing materials for
¦ sanitary materials. ~owever, the spectrum of advantages
I -17-
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s! . ` ::
3 : ::
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I ` attendant the use of superabsorbent polymers in solid and
¦ flowable,herbicidal delivery compositions have gone unrecognized.
The superabsorbent polymers of the present invention
are synthetic organic polymers which are solid and extremely
hydrophilic, absorbing over 100 times their weight in water.
Generally, these superabsorbent polymers are chosen from
acrylamide and acrylate polymers, co-polymers and ter-polymers or
starch yrafted acrylonitriles, acrylamide or acrylate polymers,
co-polymers or ter-polymer segments. These superabsorbent
polymers are typically in an extruded, powder, granule, or flake
form, adapted to be blended and/or agglomerated.
The superabsorbent polymers may be, for example, ;~
acrylamide alkali metal acrylate co-polymers; propenenitrile
homo-polymers, hydrolyzed, alkali metal salts; polymers of
propenamide and propenoic acid, alkali metal salts; hydrolyzed
acrylonitrile co-polymers, and starch graft co-polymers and ter- ~ ;
polymers thereof. All of these are designed to be hydrophilic,
absorbing over 100 times their weight in water. The resulting
hydrophilic polymers can absorb from over one hundred to greater
than about 5000, more typically around 500 to about 1,000 times `
their own weight in water ~measured using distilled water, pH ;~
7.5, 25'C, 760 mm Hg. absorption within about 30 seconds). ;~
However, the absorption or swelling capacity and absorption or ;~
swelling time typically varies with each specific superabsorbent
polymer. ~ ~ -
one class of superabsorbent polymers include
combinations of a starch and organic monomers, oligomers,
polymers, co-polymers or ter-polymers. They may be manufactured
in a variety of ways, for example the methods described in United
States Patents Nos. 4,375,535 and 4,497,930, and can be, for `~
18-
~192~ ~
example, the product of grafting corn starch (amylopectin) with
acrylonitrile (an acrylic monomer or oligomer). -
The superabsorbent polymers can also be propenoic or
acrylonitrile/acrylamide-base polymers or co-polymers or ter-
polymers that also show superabsorbency properties.
It has also been observed that superabsorbent polymers
alone, or impregnated, mixed or combined with one or more
herbicidal agent(s), with or without water or one or more
pesticidal agents or other additives have the ability to swell
differentially in water,and as hydrodynamically active carriers
release the impregnated/incorporated substance(s) at varying
rates dependent on the type of solid or flowable formulation
utilized. Superabsorbent polymers also have the ability under
certain conditions to reform or contract to a congealed or
crystal-like consistency when evaporation has caused the water to
be removed from the sol, gels or jelly-like matrix, and then
swell or regel when additional water is added. This ability to
resume a Punctional, or semifunctional, active-agent, `;
encapsulated release form after repetitive periods of wetting and
drying, is advantageous for dry or moist
preemergence/pretreatment and~or prolonged control release ~ i
applications of solid or flowable,herbicidal or
, :. :: . .:
herbicidal/pesticidal formulations. Specifically, it has been
found that when the superabsorbent polymer is impregnated or
mixed with a surfactant, surface-active agent, film-forming agent
or oil, water will be absorbed at a slower rate, so that active
agents in the solid matrix or flowable matrix formulations will
be differentially released at slower rates than would be expected
with formulations containing no surfactants, etc. This also acts ~;
as a restraint on the hydrodynamic activity of the formulation ~
: . :. ~,
-19-
... .~ ~
`: ~
;- 1331924
whPn activated, allowin~ for deactivation and subsequent
reactivation depending on environmental factors.
Non-limiting specific examples of superabsorbent ~:
polymers with differential swelling properties, and which are .
particularly use~ul in solid or flowable,herbicidal or - .
herbicidal/pesticidal delivery formulations include:
1) a co-polymer of acrylamide sodium acrylate ~Terra-
Sorb*GB);
2) hydrolyzed starch-polyacrylonitrile (Terra-Sor~
~ ) 2-propenenitrile, homo-polymer, hydrolyzed, sodium
salt or poly (acrylamide-co-sodium acrylate) or poly ~2-
propenamide-co-2-propenoic acid, sodium salt), (Water Loc ~
Superabsorbent Polymer G-100); . .
4) starch-g-poly (2-propenamide-co-2 propenoic acid,
sodium salt), (Water Loc ~ Superabsorbent Polymer A-100);
5) starch-g-poly (2-propenamide-co-2-propenoic acid,
'~odium salt), (Water Loc ~ Superabsorbent Polymer A-200);
6) starch-g-poly (2-propenamide-co-2-propenoic acid, ..
mixed sodium and aluminum salt), (Water Loc ~ Super-absorbent
polymer A-222); :~
7) starch-g-poly (2-propenamide-co-2-propenoic acid,
potassium salt), (Water Loc ~ Superabsorbent Polymer B-204);
8) poly (2-propenamide-co-2-propenoic acid, sodium
salt), (Water Lock ~ Superabsorbent Polymer G-400);
9) poly-2-propenoic acid, sodium salt (Water Loc
Superabsorbent Polymer J-500 or Aqua Keep~ J 500);
10) sodium polyacrylate superabsorbent polymers (Aqua
Keep~ J-400 and J-550);
11) starch-g-poly (acrylonitrile) or starch-~-pol.y (acryl-
amide-co-sodi.um acrylate), (General Mil].s SGP~ 502s);
-20-
*Trade mark
B
.
:
~3~1924 ~
~ .,
12) starch acrylonitrile co-polymer (Super Sorb/AG
Sorbent);
13) crosslinked modified polyacrylamides (Aquastore~ -
and Aquastor ~ F);
14) cellulosic laminates of poly-2-propenoic acid,
sodium salt (Water Loc ~ Superabsorbent Laminates L-413, L-415,
L-425, L-435, or L-513); and
15) crosslinked acrylics tAridall~ 1078, 1080, 1091,
1125, 1092, or 1098). ~ -
Superabsorbent polymers are generally nontoxia,
biodegradable, and relatively inexpensive to buy or produce. See ~;~
for example, U.S. Patents 3,661,~15 and 4,159,260.
,'',,",'' '"',','-':
Conventional herbicide and commercial formulations
that may ~ind application in the present solid or flowable,
herbiaidal delivery aompositions include Acrolein, Amitrole, `` `-
Ammonlum Sulfamate, Bromacil, Copper/Copper Sulfate, Dalapon,
Diaamba, Dichlobenil, Diquat, Diuron, Endothall, Fenac, `~
Fluridone, Glyphosate, Petroleum Solvents, Pialoram, Prometon,
Sllvex, Simazine, Tebuthiuron, Trichloroacetic Acid, 2,4-D,
Velpar, Xylene, Aquazine~, Aquathol ~, Aquashade~, Aqualir~
Banvel~, Casoro ~, Cutrin ~ Plus, Cytrol~ Amitrol ~ T, Dichlon
Dowpor~, Endothal~, Fena ~, Hydrothal~ 191, Hydrothal~ ~7, ;~
Hydout~, K-Tea~, Komeer~, Karme ~, Monuror~, Revenge~, Rode ~, ; ~ ~`
Roundup~, Saout~, Sona ~, Spik ~, System ~, System ~, Banvel~
720, Aqualin ~, Ammate~, Hyva ~, Cardi~, Tordo ~ 22K, Primato ~,
Pramitol~, Xuro ~, A~la Klee ~, Weedone~, Velpa ~, Diqua ~, and
others and mixtures thereo~. These herbicides and herbicidal
formulations, the aquakic and wetland plants that they control,
e~ective appliaation rates, etc., are discussed by W.T. Thomson,
-21- -
B
,~...,.. .,.,,, ~
~,. 133~924
1986, in Aqricultural Chemicals, Book II Herbicides, 1986-87
- Revision, Thompson Publications, Fresno, California, 301 pp.
and by Dr. Edward O. Gangstad, 1986, in Freshwater Veqetation
Mana~ement, Thomas Publications, Fresno, California, 380 pp.
Film-forming agents, surface active agents,
surfactants, or oils, useful in solid or flowable
formulations o~ the present invention as carriers, diluents,
adjuvants, release rate modifiers, insecticides, pesticides,
etc., are generally organic chemicals that are soluble to
essentially insoluble in water. ~hey are nonionic, anionic,
or cationic, generally nonvolatile, and can be liquid,
semisolid, or solid. They may have a low freezing point and
a boiling point above the maximum air temperature of the
environment into which they are placed.
Examples of liquid, semisolid, or solid film-~orming
or ~urface-active agents useful in conjunction with the
present invention for herbicidal andJor herbicidal/-
pesticidal purposes are: the organic chemicals described in
U.S. Patent No. 4,160,033; and organic chemicals that reduce
the water surface tension to greater than 31 dynes/cm and/or
have an HLB No. greater than 10. HLB stands for
"Hydrophile-Lipophile Balance", as defined in THE ATLAS HLB
SYSTEM, Atlas Chemical Industries, Inc. (4th printing), -~
1963. The HLB number is an indication of the percentage of
the hydrophilic portion of the nonionic emulsifier molecule,
as defined on pages 3 and 18 of this reference. Film~
forming or surface-active agents such as 2-propanol,
tridecyl alcohol, 2-ethyl butanol, 2-ethyl hexanol, 1-
hexanol, acetone, xylene, decyl alcohol, polyoxyethylene
~20) sorbitan trioleate, polyoxyethylene alkyl aryl ether,
polyoxyethylene (5) sorbitan monooleate, isostearyl alcohol
containing lO oxyethylene groups, Morwet~
-22-
j
.
~33~924
surfactants, isostearyl alcohol containing 20 oxyethylene
groups; cetyl alcohol; stearyl alcohol; or surface-active,
petroleum-base oils such as mineral oils, diesel oils, etc.,
and mixtures thereof may be used.
Various other exemplary surfactants include higher
fatty acids, higher alcohol sul~ates, alkyl aryl sulfonates, ~ ;
polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ~-~
~ther, polyoxyethylene sorbitan alkyl ester, polyoxyethylene
.... ...................................................................... .:., ::,
alkylamine, polyoxyethylene alkylamide, poly (oxyethylene-
oxypropylene) co-polymer and polyoxyethylene-polyoxypropylene
alkylene diamine alkyl trimethyl ammonium salt, alkyl
", :,, ." .~: ~
dimethyl benzylammonium salt, alkylpyridinium salt, alkyl
betaine or alkyl imidazoline sulfonate.
A herbicidal material is any chemical, agent, or
mixtures of chemicals and/or agents used for killing or
: ~, ,. -
controlling immature or mature stages of aquatic and wetlandplants (weeds), or for severely interrupting their normal
growth processes. Herbicidal materials may effect ` ~ ~-
preemergence or postemergence vegetation and can include
20 herbicides, desiccants, algicides, defoliants, hormones, `;~
plant growth regulators, plant growth inhibitors, petroleum `
oils or solvents, sterilants, biological control agents,
microbial control agents, pathogens and/or parasites.
I A pesticidal material is any agent, substance,
1 25 or mixture o~ agents and/or substances used to control or
kill adult or immature stages of insects (particularly
mosquitoes), snails, or other pests or organisms (i.e.,
I cercaria, miracidia) that breed in aquatic and wetland
! habitats containing aquatic and wetland plants (weeds)
or related vegetation. Exemplary pesticidal materials
can include insecticides, pesticides, molluscides, -~i~
¦ schistomacicides, ovicide~, larvicides, pupiaides,
l -23-
' ~ .
B
133192~
, ~ .
adulticides, biological control agents, microbial control
agents, pathogens, parasites, insect growth regulators,
conventional toxicants, chemosterilants, film-forming agents,
monolayers, monomolecular surface films, surface-active
agents, duplex films, petroleum oils or vegetable oils.
Pupicides, larvicides, and insect growth regulators for the ;l
control of immature mosquitoes are of specific interest.
A pupicide is any material that can kill that ;
specific developmental stage of certain aquatic insects
called a pupa. Pupicides are usually chemicals that kill
pupae directly by forming petroleum or non-petroleum films on - -
the surface of water that cause the pupae to drown. This
stage is nonfeeding and directly precedes the adult stage.
Examples of pupicides useful in accordance with the present
invention are Arosurf~ MSF or other film-forming agents
described in U.S. Patent No. 4,160,033, and petroleum oils
such as FLIT ML0~, GB-lll or GB-1356. Biological/microbial
pupae control agents such as bacteria, fungi, protozoa,
viruses, rickettsiae or nematodes may also be used at a
future time.
A larvicide is any material that can kill that
specific developmenkal stage of certain aquatic insects
called a larva. Larvicides can kill larvae after ingestion
of a toxic material, kill on or after contact with the
integument, or kill by physical (nontoxic) and/or toxic
means by causing the larvae to drown. The larval stage is
a feeding stage that usually has several molting or growth
~ phases called instars. For example, in mosquitoes there are
¦ four larval instars. The larval stage directly precedes the
pupal stage. Examples of larvicides useful in accordance
with the present invention include biological control agents
or microbial control agents such as Bacillus
-24-
',; `'
13~1924
. .:
thuringiensis var. israelensis (e.g., Vectobac~, Bactimos~
Tekna ~, Skeetal~, Mosquito Attac ~ or Bacillus sphaericus
(e.g., BSP-1); conventional toxicants such as Abate~, Bayte ~,
Dursba ~, Prento ~, Pyrenon ~, resmethrin, malathion, pyrethrins,
allethrin, Baygo ~, Furada ~, methoxychlor, etc: nonpetroleum
film-forming oils such as Arosur ~ MSF; and petroleum oils such - ~-~
as FLIT ML ~, GB-111, and GB-1356. Fungi (such as Lagenidium
~iaanteum, mycelia and oospores), protozoa, viruses, rickettsiae - ~ ~
and nematodes may also be used. ; ~;
I Insect growth regulators (IGRs) are chemicals such as
juvenile hormone or anti-juvenile hormone analogues that kill the
target aquatic environment insect in one or more immature stages -~
by adversely affecting the molting or developmental cycle. IGRs
are not considered to be direct larvicides or pupicides. For the
most part, larvae that are exposed to the chemical continue to
I develop normally until they reach the pupal stage where they die.
Examples of IGRs are Altosi ~, Dimili ~, and fenoxycarb
~Pictyl~ .
Pesticidal agents (i.e., insecticides, pupicides,
larvicides, insect growth regulators, pathogens, etc.) useful in
I the present invention are discussed in W.T. Thomas, 1985,
¦ Agricultural Chemicals, Book 1 Insecticides, 1985-86 Revision,
Thomas Publications, Fresno, California, pp. 1-255, and in George
: i
i 0. Poinar, Jr. and Gerald M. Thomas, 1978, Diagnostic Manual for
the Identification of Insect Pathogens, Plenum Press, New York, ~c
pp. 1-218.
Nontoxic adjuvant or diluent materials include water, ~ ;
carriers, binders, deflocculating agents, penetrants, spreading
agents, surface-active agents, surfactantsr suspending agents,
-3 wetting agents, stabilizing agents, compatability agents, waxes,
. : ',
-25-
`; .::
,':::
,~ 133l92~ ''".'
oils, inverting oils, co-solvents, coupling agents, foams,
synergists, anti-~oaming agents, synthetic plastics, elastomers,
natural or synthetic polymers, and other additives and mixtures
thereof.
Aquatic and wetland plants ~weeds) and related ~ -
vegetation can include algae (plankton, blue-green, green,
filamentous), ~loating plants, emersed plants, submersed plants,
shore, irrigation, and ditch bank plants, and marginal plants or
sedges, grasses, and rushes. These plants are discussed
according to family, genus and species, description, habitat,
distribution and importance, etc., by David P. Tarver, John A.
Rodgers, Michael J. Mahler and Robert L. Lazor, 1978, In Auatic
and Wetland Plants of Florida, Bureau of Aquatic Plant Research
and Control, Florida Department of Natural Resources,
Tallahassee, Florida, 127 pp. and by Dr. Edward 0. Gangstad, in ;~
Freshwater Veqetation Manaqement, 1986, Thomas Publications, ~-
Fresno, California, 380 pp.
Normally, when ~lowable formulations are made by the
addition of water or water-based herbicides or
herbicide~s)~Pesticide(s) ormu1ations to various concentrations oE
superabsorbent polymers or vice versa, sols or gels of various
aonsistencies ~viscosities) or stiffnesses can form that may or
may not be flowable. However, high-shear mixing or the addition
of various salts/electrolytes can break or interfere with the gel
~ structure or hydrogen bonding, thereby producing flowable (e.g.,
I; sprayable) superabsorbent polymer herbicide or ~ ;
I herbicide/pesticide aqueous formulations that have the desired
I viscosity. Viscosity modification will mainly be a function of
3 the active and/or inactive formulation components, the water
¦ absorption characteristics of the superabsorbent polymer (i.e.,
I -26-
T3 , , .
,, ,
, ~
1331924
the type and amount of superabsorbent polymers), shear time and
strength used to mix the formulation and/or the concentration and ~-
type of salts/electrolytes used to modify the sol or gel - -
consistency of the formulation. Therefore, the viscosity of the
formulations can be altered ~o achieve optimum flowability
droplet size and quantity, and thereby improve the general ground
or aerial application characteristics of the formulation for
maximum control of the target aquatic plant or pest. ~-
Furthermore, active insecticidal ingredients encapsulated in the
viscous/semi-viscous, flowable, aqueous superabsorbent polymer
formulation can be protected from degradation from the effects of
ultraviolet radiation, volatilization, temperature, microbial
activity, evaporation, run-off, etc., particularly when used in
preemergence/pretreatment habitats. Furthermore, evaporation of
water from the flowable formulation can result in a solid
congealed-like pesticide encapsulated matrix, thereby protecting ~i~
the active components for prolonged periods until release of the ~`
activa ingredient~s) is triggered when the habitat is flooded
with water.
As briefly discussed above, impregnation or mixing of
superabsorbent polymers with fatty alcohol film-forming agents,
,;,,, ,~ ,"
sur~aae-active aqents, surfactants, or hydrophobic oils appears
to delay or slow down the rate of water absorption of
superabsorbent polymers, thereby providing a useful mechanism for
affecting slow or controlled release of herbicidal agents or ~;
herbicidal/pesticidal agents from non-agglomerated or
agglomerated formulations in aquatic and wetland environments. `
These agents can be simply incorporated into the non-agglomerated
or agglomerated palymer matrix by mixing and subsequent
temperature or moisture treatment,thereby entrapping the
-27-
~B
.. ~ . .
133192~ ~
hydrophobic agent into a matrix. The slow or controlled release
process could be further modified or delayed by the degree of
compaction o~ the extruded powdered, crystal, or flaked
superabsorbent polymer/herbicidal or superabsorbent
polymer/herbicidal/pe~ticidal agent formulation, by varying the
size of an orifice in a container into which the herbicidal
delivery composition is placed, by varying the concentration of
adjuvants or diluents such a~ film-forming agent(s~, surface- ;
active agent(s), surfactant(s), or oil(s), by varying the
concentration of different types of superabsorbent polymer~, and
by adding one or more binders.
When used in contact with water, the water is
dif~erentially held within the gel-like or variable-viscosity,
sol-like superabsorbent polymer matrix at a stiffness or strength
that i8 dependent on whether a solid or flowable formulation is
u~ed (i.e., the amount oP water in the formulation), and
thereforQ evaporates slower than an equivalent amount of
~uperabsorbent polymer-free ~tanding water. Furthermora, the
addition o~ ~ilm-forming agents, sur~acQ-active agents,
~urfactants, or oil~ to the superabsorbent polymer(s) also
appaar~ to retard the rate of watar loss. However, eventually
the superabsorbent polymer will restore to a congealed or
arystal-like state as compared to its initial dry condition, with
loss of active agent dependent on whether it i8 mlxed in an oil,
and/or on the climatological/habitat moisture/water to which the
formulation i8 exposed. ~hese observations further suggest
additional field parsistence mechani~ms for variable-time release
(controlled release) of any active herbicidal or
herbicidal/pesticidal ingredients which are added to the solid or
~lowable superabsorbent polymer formulations.
-2~-
1331924
It should be noted that certain electrolytes or salts ~ -
(e.g., alkali metal halides such as sodium chloride, potassium
chloride, sodium sulfite, etc.) have been shown to either break
down the gel or sol superabsorbent polymer matrix when introduced ~
into water by interfering with hydrogen bonding. Various ~ ~ -
salts/electrolytes can be added separately or can be included as
an integral part of the active ingredient in the herbicidal
formulation (e.g., Aquatho ~ K contains 40.3% active ingredient
as a Dipotassium Salt of Endothall). This has an impact on, and
can be used to control the viscosity, swelling andJor water
absorbency of superabsorbent polymers, and subsequent population
control ability of the herbicidal or herbicidal/pesticidal ;-
-: ' :',; :':
delivery compositions, i.e., the release rate o~ certain
.;~.,~ .: ..
herbicidal or herbicidal/pesticidal agents that are impregnated
therewithin. Furthermore, the salt content of the aquatic
habitat can also have an effect on the kill rate of the target
species by af~ecting the solid or flowable superabsorbent po.ymer ~ ~
water absorbency, bonding, matrix swelling, breakdown, ~-
decomposition, and/or release of active herbicidal or
herbiaidal/pesticldal ingredients, which in combination with
salts/electrolytes in the Ponmulation may also affect a mechanism
to vary these factors.
Viscous/semi-viscous aqueous compositions can also be
rendered flowable by the use of vigorous or high-shear
mixing/agitation. Any suitable equipment or technique used to
inaorporate herbicides or pesticides into an aqueous emulsion can
be suitably used to render a non-flowable superabsorbent-base
composition flowable. Inverting oil techniques are also
appropriate for mixing and dispensing a highly viscous aqueous
superabsorbent polymer composition composed of water, at least
-29-
:~ ..: : . :-
~ 1331924
one herbicidal agent, film-forming agent or oil, with or without
pesticides and/or other additives. The degree of
mixing/agitation of the aqueous superabsorbent polymer-base
aqueous composition will also have an effect on the variable
release rate characteristics of active agents by effecting (i.e., ~;~
breaking or disrupting) the bonding of water with the
superabsorbent polymer matrix.
The specific gravity of the delivery composition can be
adjusted by the use of solid or liquid surfactants, oils, surface-
active or film-forming agents, alcohols, clays, talcs, fillers
which can include viscosity modifiers and the like.
The water or surfactant, surface-active agent, film-
forming agent, or oil-dissolved, -sus~ended, or -dispersed active
and inactive agents can be incorporated into the superabsorbent
polymer as an emulsion. Suitable emulsifying agents can be used
to ~orm a stable emulsion, however, an unstable emulsion may be
preferred ~or certain applications. The emulsion can also be
rendered somewhat ionic for example, by use of certain
surfactants, to promote preferable ionic bonding with the
superabsorbent polymers. Suitable emulsifiers include those
dlsclosed in U.S. Patent No. 4,606,773 or any conventional
emulsifier such as ammonium lineolate, ethylene oxide adducts,
acyl polyglycol ethers, oxyethylated fatty alcohols, alkali metal
starches as discussed in U.S. Patent No. 2,347,680, or starch
propionates as disclosed in ~.S. Patent No. 4,059,458. However,
any suitable known surfactant, surface-active agent, film-forming
agent, or oil can be employed.
The amount of active agent in the delivery composition
will depend on the target aquatic and wetland plants or related
vegetation, the active herbicidal agent involved, the
:
-30-
B -
1331924
superabsorbent polymer, whether or not water is present, and
whether any additional pesticidal agents, adjuvants and/or
diluents are added. Generally, the weight ratio of
superabsorbent polymer to herbicidal agent and any additional ;~ -
pesticidal and/or diluent or adjuvant ingredients is from about
0.1:100 to about 100:0.001, the herbicidal agent with or without
pesticidal agent being incorporated in the solid or flowable
delivery composition for application at rates at or below those
rates effective to control the target aquatic plant or pest. The ;
ratio of superabsorbent polymer(s) to any additive diluent or
adjuvant such as a surfactant, oilr surface-active agent or film-
forming agent is from about 0.1:1 to about 100:1. The ratio of
superabsorbent polymer to water in a flowable composition is
generally 0.001:100 to 1:1.
:.,
Examples I - II
Bioassays ~Table 1) to determine the efficacy of
several solid and flowable,superabsorbent polymer herbicidal or
herbicidal/pesticidal (insecticidal) formulations against floating
and submersed aquatic weeds were conducted in 5 gallon plastic
containers in a standard greenhouse (3 replications/formulation).
Representative target floating or submersed aquatic weeds were ;~
duckweed (Lemna minor), hydrilla (Hydrilla verticillata), and
water-hyacinth (Eiçhhornia crassipes). These wPeds were obtained
from infested canals in Lee County, Florida, and placed in water
or soil collected from their aquatic habitats. Aquatic weeds
were placed in containers containing 4 gallons of water obtained ;~
from the collection sites and allowed to acclimate in a ;--
greenhouse for 48 hours prior to the addition of the test
herbicidal formulations. Hydrilla were anchored in the soil ;
-31-
13~192~
substrate to a depth of ca. five inches. All containers
conta~ned five strands of hydrilla having an average wet weight
of 1.1 g per strand (12 - 15 inches per strand), and duc~weed
having an average weight of 6.8 g/container. In addition,
several containers contained 2 hyacinths at an average diameter
of 5 - 8 inches per plant.
Experimental habitats contained water-hyacinth or
combinations of hydrilla and duckweed depending on the range of
e~fectiveness of ~he herbicide(s) in the formulations.
Herbicides used in the solid or liquid superabsorbent polymer
formulations were 2,4-D, Sona ~, Diqua ~, and Diqua ~ ~ Cutrin
Plus. Arosur ~ MSF was formulated in all solid and liquid
compositions as a diluent/carrier-spreader and/or potential
mosquito larvicide and pupicide: however, mixing compatability
tests with other non-pesticidal carrier/diluents such as acetone,
hexane, ethyl alcohol, isopropyl alcohol, methyl alcohol and
xylene, and mixtures thereof, were also conducted. It should be
^noted that the mixiny compatability of all pesticidal and non-
pesticidal carrier/diluent~ were also evaluated against the
herbicide~ Hydrothol~ -191, Aquathol~ K, Cutrine~ Plus, K-Tea~,
Velpa ~, and Rode ~, and mixtures thereof. The superabsorbent
polymers Aqua Kee ~ J-500, Aquastore ~, Aquastore~ F, and Water
Loc ~ A-100 were used in the solid or liquid herbicidal test
formulations.
Herbicide(s) or herbicide(s)/insecticide(s)
, :
~ormulations were mixed with or impregnation on/in superabsorbent
polymers, with or without water, by vigorous hand-mixing or
shaking (0.5 min), with a Dynamixer at 1,800 rpm (0.5 min) and
2,400 rpm (2 min), and/or with a small electrically-powered mixer (G.E.
model 420 A) at low speed t2 ~in). The order of c~mponent m~xing was
-32-
~33192~
:.
dependent on the type of superabsorbent polymers and/or the type
of herbicidal/pesticidal ingredients.
Herbicides were ~ormulated in the solid or flowable
compositions for addition to the containers (0.0000157 surface
acre) at label-recommended per acre rates (mainly the lowest
rate) required to control the target aquatic weed populations.
Arosur ~ MSF was mixed with each solid or flowable herbicidal
composition for addition to the containers at an application rate -;~
of ca. 0.24 - 0.26 gal per surface acre of water.
Several of the herbicidal/pesticidal formulations were -~
also bioassyed against 4th instar larvae of Culex
quinauefasciatus to determine the potential mosquito-controlling
efficacy of the solid or flowable,superabsorbent polymer
herbicidal formulations. ~ -~
Comparative bioassays (Table 2) to determine the ~ ~
mosquito-controlling efficacy of several solid and flowable, ~ ~-
superabsorbent polymer herbicidal/pesticidal compositions were
conducted in 400 ml glass beakers (0.000001 surface acre)
. : ,
containing 250 ml of water purified by reverse osmosis filtration
(RØ) and 10 4th instar Culex quinquefasciatus larvae (3
replications/formulation). Application rates of Diqua ~, Diquat~
Cutrine~ Plus, 2,4-D, and Arosur ~ MSF were as indicated in the ~ ;
above mentioned container bioassay evaluations. The -~
superabsorbent polymers Aquastore~ and Aqua Kee ~ J-500 were used
in solid formulations while Aquastor ~ F, Water Loc ~ A-lO0 were
used in the flowable formulations. Solid and liquid compositions ~ -
were formulated and applied by weight (i.e., lbs per surface acre
of water). Larvae were fed a few drops of ground rabbit chow -
RØ water suspension prior to the addition of the test
formulations. ~ioassays were conducted in a room maintained at ~ ~ ;
-33- ~
~33192~
- ~.
80 F tambient) and 80% RH. Data was recorded at 24 hr
posttreatment intervals until 100% mortality was recorded.
Solid herbicidal/mosquitocidal superabsorbent polymer
formulation procedures were as follows: The desired
concentrations of Diqua ~ or Diqua ~ and Cutrin ~ Plus and
Arosur ~ MSF were added to 400 ml plastic beakers and vigorously
hand-mixed with a spatula for ca. 0.5 mi~. A small electrically-
powered mixer (G.E. model 420 A) was used to mix the formu-
lations for an additional 2 min at low speed. This formulation
was then stored i!n airtight Ziploc* plastic bags until testing.
Flowakle viscous or semi-viscous,
herbicidal/mosquitocidal superabsorbent polymer formulations used
in the bioassays were prepared in tha following manner: The
desired concentrations of Aquastor ~ F or Water Loc ~ A-loo were ~ `~
added to 100 ml plastic beakers. The desired concentration of
Arosur ~ MFS was then added to the beakers while vigorously hand-
mixing with a spatula for 0.5 min. The desired concentrations of ~ ~
~,4-D were added to separate 100 ml beakers containing R.0 water ~ ~ ;
and mixed vigorously with a spatula for 0.5 min. The water-base
herbicide was then added to a glass 100 ml medicine bottle
followed by the addition of the superabsorbent polymer/ArosurfR
MSF mixture. All components were then vigorously hand-shaken for ~ ~ -
1 min. Another procedure employed the addition of the desired
concentration of a superabsorbent polymer to a 100 ml glass `~
medicine bottle containing R.0 water and vigorously hand-shaken
for 0.5 min. Arosur ~ SF was then added to the mixture and
vigorously hand~shaken for an additional 0.5 min. A herbicide
was then added and the formulation was vigorously shaken for 1
min. The mixing technique employed was dependent on the type of
superabsorbent polymer and/or herbicide used in the formulation.
-34-
*Trade mark
,
.. .
3192~
EXAMPLE I
Results of bioassays concerning the comparative
efficacy of several solid,superabsorbent polvmer-base -`~
herbicidal/mosquitocidal formulations against floating and
submersed aquatic plants (weeds) are presented in Table 1. The
data indicated that the solid,superabsorbent polymer-base
formulations produced generally faster kill (control) of both
duckweed and hydrilla when compared to rate of kill that was
observed with the technical liquid herbicidal formulations.
Similar comparative tests with several flowable,
supsrabsorbent polymer-base herbicidal/mosquitocidal formulations
were also conducted against floating and submersed aquatic weeds ~- P
(Table 2). Results indicated that superabsorbent polymer-base
herbicidal/mosquitocidal formulations performed as good or better
than technical herbicides against duckweed, hydrilla, or water-
hyacinth. It should be noted that the viscous or semi-viscous,
~lowable formulation adhered to the leaves of the water-hyacinth
and congealed into an elastomeric or crystal-like matrix as the
water evaporated over 24 - 48 hour period. These matrices were ; ~
observed to absorb water and swell when the leaves containing the -~ ;
superabsorbent polym~r-base formulation died and fell into the
water, thereby indlcating the protective active ingredient ` ;~ `~
encapsulation/slow-release capacity of the flowable,
superabsorbent polymer-base herbicidal/mosquito~idal
formulations. It should be noted that non-target tests with
Arosur~BMSF against aquatic and wetland plants indicated that no
phytotoxicity should result when technical and water-base
Arosur ~ MSF is applied to the water surface around the plants
and/or directly on the plants at rates that are at or higher than
-35-
. 133l92~
those recommended on the label for the control of immature
mosquitoes (Levy et al. 1981. Ground and aerial application of
a monomolecular organic surface film to control salt-marsh
mosquitoes in natural habitats of Southwestern Florida. Mosauito
News 41:291-309; Hester, P. 1984. Field phytotoxicity studies
with Arosur ~ SF. R~search Report by the Department of Health
and Rehabilitative Services, West Florida Arthropod Research
Laboratory, Panama City, Florida.)
EXAMPLE II
Results of bioassays concerning the comparative
efficacy of several solid,superabsorbent polymer-base
herbicidal/mosquitocidal (Arosur ~ MSF) formulations against
fourth instar larvae of Culex auinquefasciatus are presented in
Table 3. The data indicated that solid superabsorbent polymer- ~ -
base formulations aontaining Arosur ~ MSF produced 100% mortality
of Culex larvae, pupae, and/or emerging adults within 4 - 5 days ; ;
posttreatment, while only 20-27% mortality of immature stages was
produced by the technical herbicldes. Similar results were
observed when flowable,superabsorbent polymer-base
herbicidal/mosquitocidal (Arosur ~ MSF) formulations were
evaluated agalnst Eourth instar larvae o~ Culex_quinquefasciatus
(Table 4). ReRults of the bioassays indicated that 100% of the
larvae, pupae, and/or emerging adults were killed within 5 days
post-treatment while the technical herbicide only produced ca.
53% mortality to the immature stages at this time period.
In general, the data presented in Tables 1 - 4
ind cates that the solid and flowable,herbicidal/mosauitocidal
superabsorbent polymer-base formulations can be used to
-36-
' ,''',, ' ~' ' ~' '
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1331924
simultaneously or conGurrently control mixed populations
aquatic weeds and mo~quitoes wlth a single ~or~ulation.
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