Note: Descriptions are shown in the official language in which they were submitted.
W093/25074 2 13 7 7 7 3 PCT/US93/05371
TTTT~
WATER-DISPERSIBLE GRANULAR AGRICULTURAL COMPOSITIONS
CROSS-~FF~RF~CF. TO ~T~T~.n ~PPTICATTON
This is a continuation-in-part of USSN 07/899,405
filed June 16, 1992.
This invention relates to new advantageous granular
formulations of active pesticides which are easily
dispersed or dissolved in water for application by
spraying or which may be applied as a granular
formulation directly.
Formulation of active pesticides as water-
dispersible powder compositions which can be readily
mixed with water and applied by means of a spraying
apparatus to a locus to be protected are generally
dusty, and unpleasant to handle. Granular compositions
have become very popular in recent years because they
are safer and more convenient to handle than wettable
powders.
World Patent WO 89/00079 discloses an extrusion
process to make water-dispersible granules of agricul-
tural chemicals in which water is added to make an
extrudable wet mix. The extrudate is rolled to break
the product down to granules and then optionally dried.
WO 91/13546 disclo~es pesticidal, agglomerate-type
granules. Several single component heat-activated
binders (HAB's) are exemplified but not polyethylene
glycols (PEG's). PEG's are mentioned as suitable co-
binders, but none are specifically disclosed. In
addition, PEG alone does not satisfy the requirement
specified in WO 91/13546 that the hydrophile/lipophile
balance (HLB) of the HAB be 14 to 19.
U.S. 5,013,498 teaches the preparation of small
pastilles by forcing viscous materials through small
apertures in a container into cyclical direct contact
W093/25074 2 1 3 7 7 7 3 PCT/US93/05371
with a moving surface, for example, a cooled steel
conveyor belt.
SU~M~Y OF T~F. INVTNTION
The present invention pertains to rapidly
disintegrating water-dispersible agricultural granular
compositions in the form of pastilles, agglomerates and
heat extrudate granules comprising by weight based on
the total weight of the composition:
1) 0.01-90%, preferably 0.03-80%, and most
preferred 5-75% of one or more active
ingredients;
2) 1-90%, preferably 5-60%, of one or more water-
soluble heat-activated binder (HAB) selected
from polyethylene glycol of average molecular
weight 6000 to 10,000; polyethylene oxide;
polyethoxylated fatty acids or alcohols;
ethylene oxide/propylene oxide copolymers and
polyethoxylated alkylphenols; and
3) optionally, one or more additives selected from
the group consisting of:
a) 0-10% anticaking agent(s)
b) 0-10% chemical stabilizer(s)
c) 0-20% gas generating disintegrant(s)
d) 0-10% wicking or swelling disintegrant(s)
e) 0-20% dispersant(s)
f) 0-5% wetting agent(s)
g) 0-80% inert diluent(s)
provided that (i) when the amount of active
ingredient(s) and water-soluble heat-activated binder
together are less than 100% then one or more of the
additives are required to bring the composition to
100%; (ii) when the granular composition is in the form
of agglomerates the heat activated binder is selected
from one or more of polyethylene glycol of average
molecular weight of 6000 to 10,000, polyethylene oxide,
W093/25074 ~ 2 1 3 7 7 7 ~ PCT/us93/0537l
and polyethoxylated fatty acids or alcohols; and (iii)
when the granular composition is in the form of heat
extruded granule the heat activated binder is selected
from one or more of polyethylene glycol of average
molecular weight of 6000 to 10,000, ethylene
oxide/propylene oxide copolymers and polyethoxylated
alkylphenols.
What is meant by granular is particles whether they
be agglomerates, pastilles, or extrudates of a size of
from 74 microns (200 mesh) to 8000 microns (8 mm).
The granular compositions of the invention can
consist of agglomerates comprising pesticidal particles
bonded together by solid bridges of polyethylene
glycol. The granular compositions of the invention can
also be of the form made by (1) extruding a dry premix
through a die or screen at elevated temperature and (2)
chopping, milling or otherwise breaking the extruded
material to form granules. In addition, the granular
compositions of the invention can be in the form of
pastilles made by a rotoforming process whereby a
molten slurry of the active(s) and optional additives
is drop-formed onto a moving cooling belt to form
granules.
Another embodiment of the invention is a process
for preparing the granular compositions of the
invention. One embodiment of the process for preparing
the granular compositions is directed to extrusion of a
dry premix followed by the breaking of the extrudate to
form the granular compositions. No water is added in
the extrusion process and therefore no drying of the
final products is needed.
The active ingredient is at least one pesticide or
chemical used for crop protection. More specifically,
active ingredients are selected from the class of
herbicides, fungicides, bactericides, insecticides,
W093/25074 2 1 3 7 7 7 3 4 PCT/US93/05371
insect antifeedants, acaricides, miticides,
nematocides, and plant growth regulants.
The water-soluble HAB is at least one component
selected from the group comprising polyethylene glycols
(PEG's) of average molecular weight between 6000 and
10,000; polyethylene oxide; polyethoxylated fatty acids
and alcohols; ethylene oxide/propylene oxide copolymers
(e.g., Pluronic~ F108 = a block copolymer 80% ethylene
oxide of average molecular weight 14600) and
polyethoxylated alkylphenols (e.g., Macol~ DNP150 =
dinonyl phenol with 150 moles ethoxylation). The
water-soluble HAB used for compositions involving
agglomerated-type granules is one or more selected from
polyethylene glycol of average molecular weight between
6000 to 10,000; polyethylene oxides and polyethoxylated
fatty acids and alcohols. The water-soluble HAB used
for compositions involving heat extruded type granules
is a polyethylene glycol of average molecular weight
between 6000 and 10,000. The water-soluble HAB used
for compositions involving pastille-type granules are
one or more selected from polyethylene glycol of
average molecular weight between 6000 and 10,000;
polyethylene oxide; polyethoxylated fatty acids and
alcohols; ethylene oxide/propylene oxide copolymers and
polyethoxylated alkylphenols. The preferred heat
activated binder for granular compositions are
polyethylene glycols of average molecular weight
between 6000 and 10,000. The most preferred HAB is a
PEG of average molecular weight 8000.
The process of the invention for preparing a water
dispersible agriculturally suitable granular
composition in the form of a heat extruded granule
comprising by weight based on the total weight of the
composition:
(a) 0.01-90% of one or more active ingredients;
2137773
W O 93/25074 , ~b, ', ~ PC~r/US93/0~371
(b) 1-90% of a water-soluble heat-activated binder;
selected from polyethylene glycol of average
molecular weight 6000 to 10,000, ethylene
oxide/propylene oxide copolymers and
polyethoxylated alkylphenols; and
(c) optionally one or more additives selected from
the group consisting of:
(1) 0-10% anticaking agent(s)
(2) 0-10% chemical stabilizer(s)
(3) 0-20% gas generating disintegrant(s)
(4) 0-10% wicking or swelling disintegrant(s)
(5) 0-20% dispersant~s)
(6) 0-5% wetting agent(s)
(7) 0-80% inert diluent(s)
provided that when the amount of active ingredient(s)
and water-soluble heat-activated binder together are
less than 100% then one or more of the additives are
required to bring the composition to 100%, said process
comprises feeding a dry premix of the ingredients or
feeding the ingredients in two or more streams to an
extruder with heat supplied either to the premix or the
extruder sufficient to soften the heat-activated binder
followed by cutting or breaking of the extrudate to
form granules.
DFTATT F.n DF.~C~TPTION OF T~F TNVF~NTTON
Agricultural pesticide compositions are usually
manufactured and sold as liquid or solid concentrates.
In recent years, formulations based on water-
dispersible granules have become increasingly popular
because they offer several advantages over other types
of agricultural formulations. For example, they are
stable during storage and transport. Often this is a
concern with aqueous suspension concentrates that can
settle or develop crystals in storage if the active
ingredient has slight water solubility. Also, aqueous
W093/25074 -2 1 3 7 7 7 3 PCT/US93/05371
suspension concentrates are not suitable for active
ingredients which are subject to aqueous hydrolysis.
This is not a problem with water-dispersible granules.
In contrast to wettable powders, water-dispersible
granules are convenient to handle and measure and are
relatively dust-free. They avoid the skin-toxicity and
odor problems associated with solvent-based
formulations such as emulsion concentrates and organic
suspension concentrates.
Water-dispersible granules of the invention are
used by diluting the granules in a mix tank containing
water to make a solution or dispersion which can be
sprayed. The dispersed particles formed on dilution
should be no larger than 50 microns in their largest
dimension to avoid nozzle pluggage or premature
settling which results in uneven application of the
pesticide. It is therefore necessary that all of the
components of the formulated product rapidly and
completely disperse or dissolve in the dilution water.
Optionally, under certain circumstances, these same
water-dispersible granules can be used by directly
applying them to the target without first pre-
dispersing in water. Here too, rapid granule break-up
is important so that the active ingredient is released
from the granule and becomes available as a pesticide.
Very uniform size, shape and density of the granules
are also important for application accuracy, as well as
good attrition resistance to survive conveying and
transport through application equipment.
The granular compositions of this invention are
prepared by processes advantageous over conventional
processes. Conventional methods for preparing water-
dispersible granule compositions involve (l) water-
spraying in fluidized bed or pan granulation equipment
(2) spray-drying (3) dry compaction and (4) extrusion
2137773
W093/25074 ~ PCT/US93/05371
of a water-wet paste. Granules prepared by fluid-bed,
spray-drying, pan granulation and wet extrusion can be
formulated to disperse rapidly when diluted in water.
However these processes require specialized technology
including extensive dust collection systems and a
space-consuming and expensive drying operation. Dry
compaction generally does not produce fast-dispersing
granules and the product is irregular in shape and
prone to attrition.
The present invention comprises water-dispersible
granular compositions which comprise one or more
pesticides and certain heat-activated binders. The
grar,ular compositions of the invention can be made by
preparing agglomerates comprised of pesticidal
lS particles bonded together by solid bridges of the HAB.
Advantages of the agglomerate granules are (1) the
potential for incorporation of incompatible pesticides
in the same granule, (2) low cost, (3) the simple
process required to prepare them, and (4) the lack of
the need for extensive dust collection systems and a
space-consuming and expensive drying operation.
Compositions of the instant invention can also be
made by extruding a dry premix through a die or screen
at elevated temperature and chopping, grinding or
otherwise breaking the extruded material to form
granules. Advantages of the process involving
extruding is that the extruded granular compositions
include (1) rapid disintegration and good dispersion
properties in water, (2) good attrition resistance, (3)
more uniform size and bulk density than granules
prepared by fluid-bed or pan granulation or by other
tumbling/mixing processes such as in a rotating drum
granulator, (4) simple process which uses readily
available commercial extruding equipment, and (5) no
need for drying or dust collection equipment.
W093/25074 2 1 3 7 7 7 3 PCT/US93/05371
The granular compositions can also be pastilles
made by a rotoforming process whereby a molten slurry
of the pesticide(s) and any of the optional additives
are drop-formed onto a moving cooling belt. Advantages
of the pastille granules include (1) very uniform size,
shape and density, (2) hard, smooth non-dusty forms
which have good attrition resistance, (3) are prepared
by a simple, low-cost manufacturing process, which (4)
does not involve costly drying or dust-collection
equipment.
The agglomerate granules of this invention are
prepared by any of the following processes (either in a
batch or continuous mode) whereby (1) the pesticidal
particles or active ingredient(s), the HAB particles
and optional particulate additives are tumbled/mixed
and heat is applied externally until the granules have
grown to the desired size, following which the heat is
shut-off and the granules are allowed to cool while
still tumbling or sitting in a separate container; or
where (2) the pesticidal particles or active
ingredient(s), HAB, and optional particulate additives
are intensely sheared/mixed such that frictional heat
softens the HAB thereby effecting granulation following
which the aggregates are then cooled; or where (3) the
pesticidal particles or active ingredient(s) and
optional particulate additives are tumbled/mixed and
are sprayed with the HAB which has been pre-heated and
is in a molten state following which the resulting
agglomerates are cooled.
Processes (1) and (3), involving gentle tumbling/
mixing, can be carried out in a heated fluidized bed, a
heated blender (e.g., paddle or ribbon type blenders,
vee-blenders, zig-zag blenders, Lodige~ blenders,
Nauta~ mixers) or a heated pan or drum granulator.
Process (3) may not require additional heat other than
W093/25074 ; 2 1~3 7`7 7 3 PCT/US93/05371
that needed to melt the HAB for spraying. Subsequent
cooling of the resulting agglomerates is done either in
or outside of the processing vessel. Process (2)
involving high intensity mixing/shearing can be carried
out, for example, in Schugi~ or turbulator-type
vessels. In Process (l) a preferred method of
preparing the initial mixture of particulates before
granulation is to mill the pesticidal active plus
additives and then mix (e.g., via tumbling) with HAB
particulates (e.g., of a size l0-l,000 microns).
Preparation of compositions involving more than one
active ingredient can be enhanced and incompatibility
reduced (especially when one active is present in minor
proportions) by forming granules from a particulate
premix of the major active component, HAB, and
additives, followed by introduction of the minor active
component (and optionally additional HAB), while the
granules are hot so as to imbed the second active
particulates in an HAB layer on the surface of the
first granules.
The granular compositions of this invention can
also be prepared by heat extrusion which involves a
process comprising preparing an extrudable premix by
combining the pesticidal particles with an HAB, e.g.,
PEG 8000. Other additives may optionally be included
in the premix such as wicking, swelling or gas-
generating disintegrants, one or more dispersants, and
additives such as wetting agents, anticaking agents,
chemical stabilizers, and inert diluents.
In one embodiment, the premix is blended and milled
to an average particle diameter between l and 50
microns. The milled premix is then fed or metered into
an extruder that has been heated electrically, by
steam, or by other conventional means of heating.
Suitable extruders include single and twin screw
W093/25074 2 1 3 7 7 7 3 PCT/US93/05371
models, radial extruders and roll-type extrusion
presses. In some types of extrusion equipment, for
example, a California Pellet Mill~, the heat can be
generated from friction. Other means of heating the
premix can include preheating the premix before
extrusion, or heating the individual components of the
premix before blending. The premix is heated to a
temperature in the range of about 45 to 130C,
preferably about 60 to 115C. The optimum temperature
varies with the composition but can be determined
empirically. High temperatures which can cause
decomposition of the active ingredient should be
avoided.
In a preferred extrusion process the powdered
premix ingredients are not premilled, but are fed in
two or more streams to an extruder (for example a co-
rotating or counter-rotating twin screw unit) equipped
with screw elements that facilitate dispersive and
distributive mixing. The various ingredients of the
formulation are blended, sheared, and heated in the
extruder, yielding a uniform extruded composition which
gives a good quality dispersion when added to water.
This approach is highly desirable because it eliminates
the dusty process of milling the pesticide formulation.
Other embodiments of the process of the invention will
be readily apparent. For example, the active
ingredient may be separately premilled to obtain an
optimum particle size for biological activity, and the
extruder is then used to blend the premilled active
ingredient and the unmilled formulation ingredients to
produce the desired composition.
The heated premix is extruded through a die or
screen. The die holes range in diameter from 0.25 to
7 mm, preferably from 0.4 to 2 mm. Depending on the
composition and the type of extruder used, the extruded
W093/25074 ?1~ 777 3 PCT/US93/05371
11
.
material can be recycled until the strands are uniform
in texture. Generally, the extruded material is
allowed to cool to harden and reduce stickiness,
although this is not always necessary. The strands are
chopped, milled or rolled and then screened to
approximately 10 to 60 U.S. mesh size granules. A
narrower cut size range can be selected. In some cases
the strands are sufficiently brittle that they break on
their own into short lengths.
The pastille granular compositions of this
invention are prepared in the following manner. The
active ingredient(s) and any necessary optional
additives are blended and milled as necessary to
achieve proper spray tank or biological performance.
These are then combined with the required amount of HAB
in a heated, agitated tank and the temperature of the
mixture is raised between the melting point of the
binder and that of the other additives. Temperatures
acceptable for the process are those above the melting
point of the binder and below the decomposition
temperature of the ingredients. Temperatures in the
range of 90-110C are preferred. Once the composition
is heated and well mixed, it is pumped to a feed device
which deposits a precise amount of the mix in droplet
form onto a cooling belt for ultimate solidification.
A preferred feed device is the Rotoformer~ (Sandvik~
Process Systems) although other devices such as
nozzles, injectors, and the like may be used. Once the
pastilles are deposited onto the cooling belt, they
remain a sufficient length of time to fully cool and
solidify into a hard, non-dusty granule.
The active ingredient should be chemically stable
in the temperature range required for preparing the
composition. Examples of suitable active ingredients
are listed in Table 1.
W093/25074 ~1 3 7 7 7 ~ 12 PCT/US93/05371
Herbicides such as acifluorfen, asulam, atrazine,
bensulfuron methyl, bentazon, bromacil, bromoxynil,
hydroY.ybenzonitrile, chloramben, chlorimuron ethyl,
chloroxuron, chlorsulfuron, chlorotuluron, clomazone,
cyanazine, dazomet, desmediphan, dicamba, dichlorbenil,
dichlorprop, diphenamid, dipropetryn, diuron,
thiameturon, fenac, fenuron, fluometuron, fluridone,
fomesafen, glyphosate, hexazinone, imazamethabenz,
imazaquin, imazethapyr, ioxynil, isoproturon, isouron,
isoxaben, karbutilate, lenacil, MCPA, MCPB, mefluidide,
methabenzthiauron, methazole, metribuzin, metsulfuron
methyl, monuron, naptalam, neburon, nitralin,
norflurazon, oryzalin, perfluidone, phenmedipham,
picloram, prometryn, pronamide, propazine, pyrazon,
rimsulfuron, siduron, simazine, sulfometuron methyl,
tebuthiuron, terbacil, terbuthylazine, terbutryn,
triclopyr, 2,4-D, 2,4-DB, triasulfuron, tribenuron
methyl, primisulfuron, pyrazosulfuron ethyl, N-[[(4,6-
dimethoxy-2-pyrimidinyl)amino]carbonyl]-3-~ethyl-
sulfonyl)-2-pyridinesulfonamide, nicosulfuron, and
ethametsulfuron methyl; fungicides such as carbendazim,
thiuram, dodine, chloroneb, cymoxanil, captan, folpet,
thiophanate-methyl, thiabendazole, chlorothalonil,
dichloran, captafol, iprodione, vinclozolin,
kasugamycin, thiadimenol, flutriafol, flusilazol,
hexaconazole, and fenarimol; bactericides such as
oxytetracycline dihydrate; acaricides such as
hexathizox, oxythioquinox, dienochlor, and cyhexatin;
and insecticides such as carbofuran, carbyl,
thiodicarb, deltamethrin, and tetrachlorvinphos.
The water-soluble HAB dissolve rapidly in water,
have some viscosity above their melting point and are
capable of acting as a binder when heat is applied. At
an elevated temperature the binder softens and melts,
becoming sticky enough to bind the active ingredient
W093/25074 2 1 3 7 7 7 3 PCT/USg3/05371
13
particles into larger aggregates. For the heat
extruded compositions, it is theorized that the
softened or melted HAB can also function as a plastic
or viscoelastic lubricant allowing the composition to
extrude through a die or screen. For pastilles, the
HAB acts as a thermoplastic matrix into which the
pesticidal solid particles and other ingredients are
dispersed.
The HAB must meet the following four criteria:
(1) have a melting point range within 40 to 12QaC;
(2) dissolve in mildly-agitated water in 50 minutes
or less;
(3) have a melt viscosity of at least 200 cps; and
(4) have a difference of 5C or less between the
softening point and onset of solidification.
The preferred HAB of this in~ention is PEG with an
average molecular weight between 6000 and 10,000. The
use of a PEG having the specified melt vi~cosity an~
minimum difference between softening and solidification
temperatures is necessary so that it will be tacky
enough to effect agglomeration of pesticidal particles
near the melting point of the HAB.
The compositions of this invention optionally
include the following additives which are well known in
the art:
(1) Disintegrant(s) which wick in water and
physically expand to aid break-up of the granule. Non-
limiting examples of suitable disintegrants include
starch, cross-linked polyvinylpyrrolidone (e.g.,
Polyplasdone~ XL-10), microcrystalline cellulose (e.g.,
Avicel~ series), cross-linked sodium carboxymethyl
cellulose, sodium starch glycolate, soy polysaccharide
and ion exchange resins. Cross-linked polyvinylpyr-
rolidone and cross-linked sodium carboxymethyl
cellulose are preferred.
W093/25074 2 13 7 7 7 3 14 PCT/US93/0~371
(2) Dispersant(s) which help disperse the active
ingredient in water. Preferred dispersants include
sodium and ammonium salts of naphthalene sulfonate-
formaldehyde condensates (e.g., Morwet~ D425); sodium,
calcium and ammonium salts of ligninsulfonates (e.g.,
Norlig~ lld, optionally polyethoxylated and Polyfon~
F); sodium and ammonium salts of maleic anhydride
copolymers and sodium salts of condensed phenolsulfonic
acid.
(3) Anticaking agent(s) which prevent clumping of
granules when stored under hot warehouse conditions.
Non-limiting examples include sodium and ammonium
phosphates, sodium carbonate and bicarbonate, sodium
acetate, sodium metasilicate, magnesium, zinc and
calcium sulfates, magnesium hydroxide, (all optionally
as hydrates), anhydrous calcium chloride, molecular
sieves and sodium alkylsulfosuccinates (e.g., Aerosol~
OT-B) and sodium and calcium stearates. ~oammaster~
Soap L is sodium stearate. Non-ionic and anionic
surface-active materials which may be soluble in the
HAB can also function as anti-caking aids by modifying
the melting range and tackiness of the HAB. These may
optionally be predissolved or predispersed in molten
HAB prior to formulation of the premix. Non-limiting
examples include polyethoxylated alkylphenols (e.g.,
Triton~ X-100), polyethoxylated fatty acids or
alcohols, and silicone-based surfactants (Silwet~
L-77)-
(4) Chemical stabilizer(s) which prevent
decomposition of the active(s) during storage. Non-
limiting examples of suitable chemical stabilizers
include alkaline earth and transition metal sulfates
such as magnesium, zinc, aluminum and iron, sodium
hexametaphosphate, sodium pyrophosphate, calcium
3S chloride and boric anhydride.
W093/25074 2 1 3 7 7 7 3 PCT/US93/05371
(5) Gas producing disintegrant(s) for faster
break-up of the granule in water. Non-limiting
examples of suitable gas generating additives are
combinations of sodium and potassium bicarbonates and
carbonates which may be combined with acids such as
citric and fumaric acid.
(6) Wetting agent(s) which improve the speed of
wetting upon mixing with water. Non-limiting examples
of anionic wetting agents include sodium salts of alkyl
naphthalene sulfonates (e.g., Petro0 Ag-Special), alkyl
benzene sulfonates, alkyl sulfosuccinates, taurates,
alkyl sulfates and phosphate esters. Examples of
suitable nonionic wetting agents include acetylenic
diols and alkyl phenol ethoxylates.
(7) Diluent(s), including but not limited to
inorganic fillers well known in the art. Non-limiting
examples are swelling and non-swelling clays, synthetic
and diatomaceous silicas (e.g., Wessalon~ 50S), calcium
and magnesium silicates, talc, titanium dioxide,
aluminum, calcium and zinc oxide, calcium and magnesium
carbonate, and charcoal. Non-limiting examples of
water-soluble diluents include sodium acetate,
ammonium, sodium and potassium sulfate, sucrose,
dextrin, urea, lactose, and sorbitol. Water-soluble
polymers may be added to improve rheology. Non-
limiting examples include methylcellulose, hydroxy-
ethylcellulose, starch, and polyvinylpyrrolidone.
The granules of this invention break-up rapidly and
form high quality dispersions in water as determined
from the Long Tube Sedimentation test described in U.S.
3,920,442, Col. 9, lines 1 to 39. Acceptable Long Tube
Sedimentation values correspond to less than 0.02 mL,
preferably less than 0.01 mL, of solids after 5 minutes
of settling.
'' ' ' ' ' PCI /US93/05371
W093/25074 2 1 3 7 7 7 3 16
The break-up times in water should be less than ~
minutes and preferably less than 3 minutes. Break-up
time is measured by adding a sample of the granules
(0.5 g, 74 to 2,000 microns) to a 100 mL graduated
cylinder (internal height after stoppering is 22.5 cm;
I.D. is 28 mm) containing 90 mL of distilled water at
25C, following which the cylinder is clamped in the
center, stoppered, and rotated about the center at
8 rpm until the sample is completely broken up in the
water.
The granules should exhibit low attrition
characteristics which can be determined by the
attrition test in U.S. 3,920,442 (Col. 8, lines 5-48).
The test is modified to use test samples of the
commercial granule size (e.g., 74-2,000 microns).
Attrition values of less than 40% and preferably less
than 30% are acceptable.
The granules should also resist caking. This
property is determined by taping a stainless steel disc
(0.9 mm thick x 51 mm diameter) to the bottom of a
glass cylinder (96.5 mm I.D. x 75 mm length x 51 mm
O.D.). Twenty grams of the granular sample is poured
into the cylinder assembly and leveled, and a second
stainless steel disc (0.9 mm thick x 44.5 mm diameter)
is placed on top of the granules. A 390 g weight is
then placed on top of the inner disc, and the entire
assembly is sealed in a glass jar and placed in a 54C
o~en for 1 or 2 weeks. The assembly is then removed
from the oven, the weight is remo~ed, and the sample is
allowed to cool to room temperature. The bottom disc
is then detached and if the sample flows out of the
cylinder, the resistance to caking is excellent. If
the sample remains in the cylinder, the cake is gently
pushed out onto a flat surface and a penetrometer
fitted with a single-edged razor blade is used to
W093/25074 . . i~13.7} 7~7 3 PCT/US93,0s3,l
17
measure the minimum force necessary to cleave the cake.
If no weight other than the weight of the razor blade
and spindle assembly is needed, the caking resistance
is still considered excellent. The Examples below show
the grams force of additional weight required to cleave
the cake. Cakes requiring less than 200 g force are
considered acceptable.
The CIPAC test was used in some of the Examples to
measure caking. The CIPAC Method used is MT 172,
"Flowability of Water Dispersible Granules after Heat
Test Under Pressure.
The following Examples are presented to illustrate,
but not restrict, this invention.
~ntity of In~re~;~nts Use~ in ~.
~ lont ~ t;y
Norlig0 lld calcium lignosulfate (dispersant)
Foammaster~ Soap L sodium stearate (anticaklng agent)
Brij0 700 polyoxyethylene (100) stearyl ether
(anticaking agent)
Morwet~ D425 sodium naphthalene formaldehyde condensate
(dispersant)
Petro0 AG-Special sodium alkylnaphthalene sulfonate (wetting
agent)
Polyfon~ AF sodium modified kraft lignin (dispersant)
Polyplasdone0 XL-10 crosslinked polyvinylpyrrolidone
(disintegrant)
Aerosol0 OT-B sodium dioctyl sulfosuccinate (anticaking
agent)
Silwet0 L-77 silicone-polyether copolymer (anticaking
agent)
Masil0 280LP silicone surfactant (wetting agent~
Wessalon~ 50S precipitated silica (diluent~
~X~MPT.~. 1
Thirty grams of metsulfuron methyl, 7.5 g of
Norlig~ lld, 0.75 g of Foammaster~ Soap L, and 93.75 g
of potassium sulfate were milled using a Bantam0
Mikropulverizer with a 0.027 round hole screen one
W O 93/25074 213 7 7 7 3 PC~r/US93/05371
18
pass. The premix and 18 g of CarbowaY~ PEG 8000 binder
(size range = about 37-545 microns, median diameter =
159 microns), were added to a laboratory twin shell
(Vee) blender and the blender was tumbled. Heat was
added using a laboratory hot air gun and the
temperature in the blender was monitored. When the
temperature reached 70C the heat was removed and the
tumbling was continued until the temperatures of the
granules dropped below 50C. The granules were then
removed from the blender and the product cut was taken
by sifting using a laboratory Gilson~ sieve shaker
fitted with a 14 mesh (1410 microns) and a 200 mesh
(74 microns) screen. The 136.2 g of product obtained
in this way was a non-dusty, agglomerated granular
composition.
PROPFRTT~S OF ~R~UT.~..~
Long Tube Sedimentation (mL, 5 min.)trace
Break-up (s) 102
Attrition (%) 19.7
20 Caking (g)
O .O,
partially flowed out of cylinder (100 h at 54C)
After aging 2 weeks at 54C:
Decomposition of active (%) <3
25 Long Tube Sedimentation (mL, 5 min.) 0
Break-up (s) 108
Attrition (%) 25
F.~ Z~qP T ,F. ~7
This composition was prepared by the same process
used to prepare that of Example 1. The quantities of
each component were the same except that 0.5% (0.75 g)
of Witco~ calcium stearate was added and 93.00 g of
potassium sulfate was used. The calcium stearate was
post-blended after the granules were formed and the
granulation mass cooled to 50C. The granulation mass
W093/25074 2 1 3 7 7 7 3 PCT/USg3/05371
19
and the calcium stearate were blended at 50C for 5
min. before discharging the granules. 145.9 g of
14/200 mesh non-dusty agglomerate-type granules were
recovered.
5 PROP~RT TF. S OF GR~UT~S:
Long Tube Sedimentation (mL, 5 min.) trace
Break-up (s) 48
Attrition (%) 1.7
Caking (g)
10 0.0,
partially flowed out of cylinder (100 h at 54C)
Caking (% through screen) 78
after 20 taps according to the CIPAC test
After aging 2 weeks at 54C:
15 Decomposition of active (%) <5
Long Tube Sedimentation (mL, 5 min.) trace
Break-up (s) 48
Attrition (%) 3.3
F.XAMPT.F. 3
The active pesticide, 122.1 g of sodium 2-chloro-6-
[(4,6-dimethoxy-2-pyrimidinyl)thio]benzoate, and 8.1 g
of potassium sulfate were ground in a CRC0 analytical
laboratory mill. The blend was then added along with
19.8 g of Carbowax~ PEG 8000 to a Vee-blender and the
blender was tumbled. Heat was added using a laboratory
hot air gun and the temperature in the blender was
monitored. When the temperature reached 70C the heat
was removed and the tumbling was continued until the
temperatures of the granules dropped below 50C. The
30 granules were then removed from the blender and the
product cut was taken by sifting using a laboratory
Gilson0 sieve shaker fitted with a 14 mesh
(1410 microns) and a 200 mesh (74 microns) screen.
133 g of 14/200 mesh granules were obtained.
W093/2~074 ~ PCT/US93/05371
2137773 20
PROPFRTIFS OF GR~UTFS:
Long Tube Sedimentation (mL, 5 min.) 0
Break-up (s) 24
Attrition (%) 10
5 Caking (% through screen) 86
after 20 taps according to the CIPAC test
FX~MPTF 4
A composition was prepared by hammermilling 160 g
of metsulfuron methyl, 64 g of Norlig~ lld and 488 g
of potassium sulfate with a 027 round hole screen.
This powder was combined with 88 g of Carbowax~
PEG 8000 in a laboratory 2-quart Patterson Kelly~ Vee
blender. Heat was applied with a laboratory heat gun
while the Vee blender was rotating. After reaching
65C, the heat was turned off and the granules were
allowed to cool to less than 50C while tumbling in the
blender. Recovered were 778 g of non-dusty 14/200 mesh
granules.
PROPFRT TF. S OF ~.R~UT F.~
20 Long Tube Sedimentation (mL, 5 min.) trace
Break-up (s) 42
Attrition (%)
Caking (% through screen) 48
after 20 taps according to the CIPAC test
FX~MPTF 5
Tribenuron methyl sodium salt (50.0 g) and
Glacier~ talc 325 (10 g) were ground in a CRC~
analytical laboratory mill. The powder was then added
along with Carbowa~D PEG 8000 (15 g) to a Vee blender
and granulated as noted in E~.ample 1. 51.9 g of 14/200
mesh granules were obtained (69.2% yield from starting
amounts).
PROPFRTIFS OF GRA~UTFS:
Long Tube Sedimentation (mL, 5 min.) 0
35 Break-up (s) 36
W093/25074 21 3 7 7 7 3 PCT/US93/05371
21 `
Attrition (~) 1.4
Caking (g, after 100 h at 54C) 50,
After aging 2 weeks at 54C:
Decomposition of active (%) <1
F.X~MPT.F. 6
Tribenuron methyl sodium salt (50.0 g) and
Glacier~ talc 325 (6.2 g) were ground in a CRC mill.
The binder was prepared by melting together Carbowax~
95% PEG 8000 powder (15 g) and sodium stearate (3.75 g)
in a vacuum oven at 110C for 16 h. After cooling to
room temperature, the solid was ground in a mortar and
pestle and sieved through a 35 mesh screen
(500 microns). The binder mixture was then added along
with the active and talc powder to a Vee blender and
granulated as noted in Example 1. 61.4 grams of 14/200
mesh granules were obtained.
PROP~RTTFS OF GR~UT.F.S
Long Tube Sedimentation (mL, 5 min.) 0
Break-up (s) 60
20 Attrition (%) 1.8
Caking (g, after 100 h at 54C) 50,
After aging 2 weeks at 54C:
Decomposition of active (%) <5
F.~MP T .F. 7
Metsulfuron methyl (84 g) was combined with
Foammaster~ Soap L (0.7 g), Norlig~ lld (11.2 g),
sodium pyrophosphate (14 g) and potassium sulfate
(14.7 g) in a CRC~ analytical laboratory mill. The
premix was then combined with Carbowax~ PEG 8000
(15.4 g) in a Vee blender and granulated as noted in
Example 1. 125.8 grams of 14/200 mesh granules were
obtained.
PROPFRTIFS OF GR~UTFS:
Long Tube Sedimentation (mL, 5 min.) trace
3S Break-up (s) 45
W093/25074 2 1 3 7 7 7 3 22 PCT/US93/05371
Attrition (%) 6.3
Caking (g, 100 h at 54C) 100
F~X Z~MP T .F~ 8
Tribenuron methyl sodium salt (333.0 g), Carbowax0
PEG 8000 (115 g) and 10X sugar (62 g) were combined in
a 2-quart Patterson Kelly0 Vee Blender (twin shell)
with intensifier bar. None of the formulation
ingredients were milled. The blender was rotated and
the intensifier bar turned on. Heat was applied using
a laboratory heat gun. When the granulation mass
reached 70C, the heat was turned off and the
intensifier bar was stopped, and the granulation mass
was cooled to less than 50C. 477.5 g of non-dusty
14/200 mesh granules were recovered.
15 PROP~TT~S OF ~A~UT~.~
Long Tube Sedimentation (mL, 5 min.) 0
Break-up (s) 54
Attrition (%) 0.7
F'.X~MP T .F~ 9
This Example illustrates melt extrusion of a water-
soluble active ingredient, tribenuron methyl sodium
salt, at 55 wt. ~ concentration.
300 grams of premix were formulated from the
ingredients listed below. The ingredients were blended
and then passed through a MikroPulverizer0 hammer
mill. 139 grams of milled premix was slowly added to a
1 inch Wayne0 single screw extruder with a 24:1 L/D
ratio. A 2:1 compression ratio screw was u-~ed for most
of the runs. The extruder had three electrical heating
zones along the barrel plus a band heater for the die.
The feed throat was water-cooled. A mechanical or
electronic pressure indicator was fitted near the end
of the barrel to measure melt pressures close to the
die.
2i37773
W093/25074 PCT/US93/0~371
23
The premix was extruded through a die containing 8
x 0.9 mm holes arranged in a circular pattern. The
extrudate consisted of smooth, continuous strands of
uniform appearance. The strands were allowed to cool
for a few minutes and then were chopped up in a small
food processor and screened to obtain the 14 to 35 U.S.
sieve cut size.
P~FMTX COMPOSITION: Wt. %
tribenuron methyl sodium salt 55.0
PEG 8000 (Carbowax~) 22.0
NaHCO3 3.0
810 Calcium Carbonate 20.0
FXTRUDFR OPF~ATING CONDIT~ONS:
Barrel temperature ranges (C) at:
feed zone 35-49
transition zone 55-59
metering zone 91-96
die 101-108
Screw Speed (rpm) 20-30
Melt Pressure Range (106 Pa): 13.1-31.0
PROPF~TTF~ OF ~UTF~:
Long Tube Sedimentation (mL, 5 min.) 0.004
Long Tube Sedimentation (mL,1 week at 54C) trace
Untapped Bulk Density (g/l) 839
Caking (g) 0.0,
partially flowed out of cylinder (1 week at 54C)
F~AMPTF 10
The composition of this Example was prepared in the
same way as that identical to Example 9 but contains
65 wt. % tribenuron methyl sodium salt. The
formulation also contains a dispersant to improve the
Long Tube Sedimentation results. 229 g of milled
premix was fed into the extruder.
:
W093/25074 , ~ ,~ PCT/US93/05371
2137773 24
p~F.~TX COMPOSITION Wt. %
tribenuron methyl sodium salt 65.0
PEG 8000 (Carbowax~) 27.0
NaHCO3 3.0
5 Morwet~ D425 1.0
810 Calcium Carbonate 4.0
~XTRUDF.~ OP~ATING CONDITIONS:
Barrel temperature ranges (C) at:
feed zone 30-39
transition zone 48-59
metering zone 78-82
die 97-98
Screw Speed (rpm) 30
Melt Pressure Range (106 Pa) 22.1-24.8
PROP~TI~S OF GRANUT~S:
Long Tube Sedimentation (mL, 5 min.)0.0
Long Tube Sedimentation (mL, 2 weeks at 54C)trace
Untapped Bulk Density (g/l) 769
Caking (g) 0.0,
partially flowed out of cylinder (2 weeks at 54C)
F~AMPTF 11
The composition of this Example was prepared by the
same process as that of Example 9. This composition
contains 70 wt. % tribenuron methyl sodium salt, and a
polyethoxylated alcohol surfactant, Brij~ 700, co-
melted with the Carbowax~ PEG 8000 to help caking
performance. No diluent, disintegrant or dispersant
are included in this composition. 130 grams of milled
premix was fed into the extruder.
30 P~FMTX CO~POSTTION Wt. %
tribenuron methyl sodium salt 70.0
PEG 8000 (Carbowax~) 28.2
Brij~ 700 1.8
W093/25074 2 1 3 7 7 7 3 PCT/US93/05371
F.XTRUDF.R OPF.~ATING CONDITIONS:
Barrel temperature ranges (C) at:
feed zone 29-35
transition zone 54-59
metering zone 90-91
die 97-103
Screw Speed (rpm) 30
Melt Pressure Range (106 Pa) 4.83-13.8
PROPFRTTF.S OF GR~NUT.F.S:
Long Tube Sedimentation (mL, 1 week at 54C) 0
Untapped Bulk Density (g/l) 735
Caking (g) 0.0,
partially flowed out of cylinder (1 week at 54C)
F.X~MP T.~
This Example illustrates extrusion of the
composition of Example 10 without milling the premix.
The ingredients were simply blended together and 200 g
was then fed into the extruder which provided the
necessary mixing and shearing to yield a uniform
extrudate.
F.XTRUDF.R OpF.~ATING CONDITTON.S:
Barrel temperature ranges (C) at:
feed zone 27-32
transition zone 49-54
metering zone 80-81
die 95~97
Screw Speed (rpm) 30
Melt Pressure Range (106 Pa) 22.1-23.4
PROPF.RTIF.S OF GR~NUT.F.S
30 Long Tube Sedimentation (mL, 5 min.)0.0
Untapped Bulk Density (g/l) 762
F.XZ~I'IPT.~. 13
This Example illustrates the melt extrusion of a
water-insoluble active ingredient, chlorimuron ethyl.
120 grams of milled premix were fed into the extruder.
W093/25074 213 7 7 7 3 PCT/US93/05371
26
A tacky extrudate was obtained which quickly hardened
and lost tackiness as it cooled.
p~F.~IX CO~POSITION Wt. %
chlorimuron ethyl 63.0
PEG 8000 (Carbowax~) 16.7
Aerosol~ OT-B 3.0
NaHCO3 3.0
Polyplasdone~ XL-10 2.0
810 Calcium Carbonate 12.3
FXTRUDF~ OP~ATING CONDITIONS:
Barrel temperature ranges (C) at:
feed zone 32-48
transition zone 52-53
metering zone 54-55
die 60
Screw Speed (rpm) 20-30
Melt Pressure Range (106 Pa) 1.38-4.14
PROPF~TIF.~ OF ~RP~UT.F.S
Long Tube Sedimentation (mL, 5 min.) 0.008
Long Tube Sedimentation (mL, 1 week at 54C) 0.004
Untapped Bulk Density (g/l) 756
Caking (g, 1 week at 54C) 201
F.XAMPT.F. 14
Five grams of sulfometuron methyl were added to a
premelted blend of 4.4 g CarbowaY.~ PEG 8000 and 0.3 g
Silwet0 L-77 in a small petri dish. To this was added
0.3 g of Petro~ AG-Special. The temperature of the
slurry was maintained between 90 and 110C. A pointed
spatula was used to deposit a drop of the slurry
approY.imately 1.0 to 2.0 mm in diameter onto a
stainless steel plate at room temperature and the drop
was allowed to cool completely. This drop-and-cool
process was used to make enough "pastilles" to run
break-up and caking tests, using granules in the range
of 0.85 to 2.0 mm for all tests. After aging for 2
-21~7773
W093/25074 PCT/US93/05371
27 ^~
weeks at 54C, there was only a slight tendency for the
pastilles to cake. Also, break-up time was less than 3
min.
F.XAMPT.F. 1 5
Five grams of bensulfuron methyl were added to a
premelted blend of 4.7 g Carbowax~ PEG 8000 and 0.3 g
Silwet0 L-77 in a small petri dish. The temperature
of the slurry was maintained between 90 and 110C. A
pointed spatula was used to deposit a drop of the
slurry approximately 1.0 to 2.0 mm in diameter onto a
stainless steel plate at room temperature and the drop
was allowed to cool completely. This drop-and-cool
process was used to make enough "pastilles" to run
break-up and caking tests, using granules in the range
of 0.85 to 2.0 mm for all tests. Results of a modified
caking test (5 g sample is placed into a 30 mm diameter
tube with 150 pounds per square foot loading and aged
100 h at 54C) show these pastilles to have no caking
tendency.
F.XAMPT.~. 16
Using the same procedures as described in Examples
14 and 15, 5 g of diuron technical, 4.9 g of Carbowax0
PEG 8000 and 0.1 g of Masil0 280LP were used to make
the test pastilles. Caking results by the modified
100 h/54C test showed only a very slight, acceptable
caking tendency. A break-up test on these granules
showed essentially all material fully dispersed in less
than 5 min.
F.XAMPT.F. 17
Using the same procedures as described in Examples
14 and 15, 5 g of sulfometuron methyl, 4.1 g of
Carbowax0 PEG 8000, 0.3 g of Silwet0 L-77 and 0.6 g of
Polyfon0 F were used to make the test pastilles. A
break-up test on these granules showed complete
dispersion within 3 min.
W093t25074 PCT/US93/05371
2137773 28
F.XZ~MPT.F. 18
This example demonstrates dry radial extrusion
using Carbowax~ PEG 8000 with a water soluble-active
ingredient, tribenuron methyl sodium salt at 57% active
concentration.
100 grams of premix were formulated from the
ingredients listed below. The ingredients were
blended and then passed through a CRC mill. The
milled premix was then added to a V-blender and heated
to 60C while agitating. The hot premix was then
added to the Luwa Benchtop granulator (radial
extruder), and the premix was extruded through a
1.0 mm screen. The basket of the granulator was
heated with a heat gun before the premix was added for
extrusion. A small amount of powder exited the screen
before the extrudate started to form. The extrudate
consisted of long smooth strands which hardened
quickly (1-2 min.). The extrudate was then screened
to obtain a 14/60 mesh product cut. The screened
extrudate are cylinders approximately 1 mm in diameter
and 5 mm in length.
p~.~TX CO~POSITIQN: Wt. %
PEG 8000 (Carbowax~) 35
tribenuron methyl sodium salt (92. 8%) 62
25 Wessalon~ 50S 3
PROPFRTTFS OF GR~NUTFS
Long Tube Sedimentation ~mL, 5 min.) trace
Break-up (s) 75
Caking (100 h at 54C)
Particles flowed freely from the caking tube with a
slight tap.
F.X P.r`lP T ,F. 19
This Example demonstrates dry radial extrusion
using Carbowax~ PEG 8000 with metsulfuron methyl at
35 18% active concentration. 100 grams of premix were
W093/25074 -2 1 3 7 7 7 3 pCT/US93/0537l
29
formulated from the ingredients listed below. The
ingredients were blended and then passed through a
CRC~ analytical laboratory mill. The milled premix
was then heated in a vacuum oven to 60C. The hot
premix was then added to the Luwa Benchtop granulator
(radial extruder). The basket of the granulator was
heated with a heat gun before the premix was added for
extrusion. The premix was extruded through a 0.8 mm
screen. A small amount of powder exited the screen
before the extrudate started to form. The extrudate
consisted of long smooth strands which hardened quickly
~1-2 min.). The extrudate was then screened to obtain
a 14/60 mesh product cut. The extrudate was very hard,
and had a diameter of 0.8 mm and a length of
15 approximately 5 mm.
p~F.MTX COMPOSITION: Wt. %
metsulfuron methyl (97.0%) 18.0
Norlig~ lld 6.0
anhydrous K2SO4 50.0
20 anhydrous Na2CO3 2.0
anhydrous sodium metaphosphate2.0
sugar 1.0
anhydrous Mg2SO4 2.0
Carbowax~ PEG 8000 19.0
25 PROPFRTI~S OF G~ANUT.F.S
Long Tube Sedimentation (mL, 5 min.) trace
Break-up (s) 75
