Note: Descriptions are shown in the official language in which they were submitted.
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COMPOSITIONS WITH HOT MELT RESIN MATRIX
BACKGROUND OF THE INVENTION
[0001] Ethylene is an important regulator for the growth, development,
senescence, and
environmental stress of plants, mainly affecting related processes of plant
ripening, flower
senescence and leaf abscission. Ethylene is usually generated in large amounts
during growth of
plants under environmental stress or during preservation and delivery of
plants. Therefore yield
of plants such as fruit and crop can be reduced under heat or drought stress
before harvesting.
The commercial value of fresh plants such as vegetables, fruits and flowers
after harvesting is
reduced by excessive ethylene gas which hastens the ripening of fruits, the
senescence of flowers
and the early abscission of leaves.
[0002] To prevent the adverse effects of ethylene, 1-methylcyclopropene
(1-MCP) is used to
occupy ethylene receptor and therefore ethylene cannot bind and elicit action.
The affinity of 1-
MCP for the receptor is approximately 10 times greater than that of ethylene
for the receptor. 1-
MCP also influences biosynthesis in some species through feedback inhibition.
Thus, 1-MCP is
widely used for fresh retention post-harvest and plant protection pre-harvest.
[0003] But 1-MCP is difficult to handle because it is gas with high
chemical activity. To
overcome this problem, 1-MCP gas has been encapsulated successfully by oil-in-
water emulsion
with 1-MCP gas dissolved in internal oil phase, but 1-MCP concentration in
final product is still
low (<50 ppm).
[0004] Therefore, in current agricultural applications, 1-MCP is complexed
with
cyclodextrin to form a powder, and 1-MCP can be released as a gas when the
powder is
dissolved in water. The powder products are much more convenient to use than
products in gas
form, but they still have disadvantages including: (1) it is not user-friendly
when handling
powder in the field or in an enclosed space; (2) the powder form cannot stably
and uniformly be
suspend in water, which leads to non-uniform delivery of 1-MCP to plants and
uneven ripening
response of plants; and (3) after contact with water, 1-MCP is released
completely within a short
period of time, much earlier than desired, some or all of 1-MCP is thus lost
to the surroundings.
Therefore, 1-MCP powder products are not properly formulated for use in water
that is suitable
for delaying plant maturation in the field.
[0005] In addition, efforts to solve above problems include mixing 1-MCP
complex powder
with other powders form materials, then preparing effervescent tablets or
enclosing the mixture
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in a water impermeable container. But such modified compositions still have
disadvantages
including: (1) similar to the limitations of powders, they are still limited
in applications since
they usually require air circulation to ensure uniform distribution of 1-MCP,
which is not
available in field application; and (2) they cannot be used by spraying in the
field. Thus, there
remains a need for compositions for delivery of compounds including
cyclopropenes or other
plant growth regulators without these disadvantages.
SUMMARY OF THE INVENTION
[0006] Provided are compositions comprising a collection of coated
particles, wherein the
coated particles comprises an active ingredient dispersed in an resin matrix;
and a coating
comprising at least one hydrophobic compound. Also provided are methods for
preparing
compositions comprising: (a) blending an active ingredient (for example, 1-MCP
complex
powder) with resin at the temperature slightly over the melting point of the
resin; (b) dispersing
the blend into an oil medium containing hydrophobic particles by shearing and
obtain an oil
dispersion; and (c) consolidating the resin particles by cooling. Thus, the
active ingredient (for
example, 1-MCP complex powder) is imbedded in the resin matrix spheres, and
the hydrophobic
particles, which also serve as Pickering emulsifier to stabilize the matrix
spheres, form a coating
layer around the matrix spheres to provide protection against water. Thus, the
sphere is
composed of the "Pickering" particle and resin matrix, in which the active
ingredient is
imbedded.
[0007] In one aspect, provided is a composition comprising a collection of
coated particles,
wherein each of the coated particles comprises,
(a) an active ingredient dispersed in an resin matrix; and
(b) a coating comprising at least one hydrophobic compound.
[0008] In one embodiment of the compositions provided, the active
ingredient comprises a
volatile compound. In a further embodiment, the volatile compound comprises a
cyclopropene.
In a further embodiment, the cyclopropene comprises 1-methylcyclopropene (1-
MCP). In
another embodiment, the active ingredient comprises a complex comprising a
cyclopropene and
a molecular encapsulating agent. In a further embodiment, the molecular
encapsulating agent
comprises alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, or
combinations thereof
[0009] In one embodiment, the active ingredient comprises a plant growth
regulator. In
another embodiment the resin matrix comprises polyester resins. In another
embodiment, the
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resin matrix comprises polyester, polyether, epoxy resin, isocyanate, ethylene
vinyl acetate
copolymer, natural or synthesized wax, or combinations thereof. In another
embodiment, the
resin matrix comprises polycaprolactone polyols.
[0010] In one embodiment, the polycaprolactone polyols have molecular
weight from 1,000
to 200,000; from 2,000 to 50,000; from 2,000 to 8,000; or from 2,000 to 4,000.
In another
embodiment, the polycaprolactone polyols have a melting point from 30 C to
120 C; from 40
C to 80 C; or from 50 C to 60 C. In another embodiment, the at least one
hydrophobic
compound comprises hydrophobic silica. In a further embodiment, silica surface
of the
hydrophobic silica is modified by silane coupling agent or organosilicon. In
another
embodiment, the at least one hydrophobic compound comprises hydrophobic
particles. In a
further embodiment, the hydrophobic particles function as Pickering emulsifier
and comprise
silica particles, clay, oxides, polymer particles, or combinations thereof.
[0011] In one embodiment, particle sizes of the coated particles are
from 10 nanometers to
200 microns. In a further embodiment, particle sizes of the coated particles
are from 10
nanometers to 10 microns. In another further embodiment, particle sizes of the
coated particles
are from 100 nanometers to 5 microns. In another further embodiment, particle
sizes of the
coated particles are from 5 microns to 200 microns. In another embodiment, the
composition
provided further comprising at least one surfactant. In another embodiment,
the composition
provided does not comprises a surfactant. In another embodiment, the at least
one surfactant
comprises anionic surfactant, nonionic surfactant, or combinations thereof In
a further
embodiment, the at least one surfactant comprises an ionic surfactant selected
from the group
consisting of sulfate salt, sulfonate salt, and combinations thereof In
another further
embodiment, the at least one surfactant comprises a nonionic surfactant
selected from the group
consisting of ethoxylates of fatty alcohol, ethoxylate of fatty acids, block
copolymer of
polyoxyethylene and polyolefin, and combinations thereof. In another
embodiment, ratio of the
active ingredient to the resin matrix is from about 1:1 to about 1:100. In
another embodiment,
ratio of the active ingredient to the resin matrix is from about 1:2 to about
1:100. In another
embodiment, ratio of the active ingredient to the resin matrix is at least
1:1. In another
embodiment, ratio of the active ingredient to the resin matrix is less than
1:100.
[0012] In another aspect, provided is method for preparing a composition,
comprising,
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(a) blending an active ingredient with resin at a temperature higher than
melting point of
the resin;
(b) dispersing the blend of step (a) into an oil medium containing hydrophobic
particles;
and
(c) consolidating Pickering particles by cooling to a temperature lower than
the melting
point of the resin.
[0013] In one embodiment, the oil medium comprises a mixture of alkanes
of C14 to C50, or
a distillate of petroleum. In another embodiment, the oil medium comprises
mineral oil, light
mineral oils, Isopar oil, Unipar oil and other hydrocarbon oils, edible oils,
or combinations
thereof In another embodiment, the temperature lower than the melting point of
the resin is
ambient temperature. In another embodiment, ratio of the Pickering particles
to the oil medium
is from about 1:5 to about 1:25. In another embodiment, ratio of the Pickering
particles to the oil
medium is from about 1:10 to about 1:24. In another embodiment, ratio of the
resin matrix to the
oil medium is from about 2:1 to about 1:100. In another embodiment, ratio of
the resin matrix to
the oil medium is from about 1:1 to about 1:100. In another embodiment, ratio
of the active
ingredient to the resin matrix is from about 1:1 to about 1:100. In another
embodiment, ratio of
the active ingredient to the resin matrix is from about 1:2 to about 1:100. In
another embodiment,
ratio of the active ingredient to the resin matrix is at least 1:1. In another
embodiment, ratio of
the active ingredient to the resin matrix is less than 1:100.
[0014] In another aspect, provided is a slurry comprising an aqueous medium
and a
collection of coated particles, wherein each of the coated particles
comprises,
(a) an active ingredient dispersed in an resin matrix; and
(b) a coating comprising at least one hydrophobic compound.
[0015] In one embodiment of the slurries provided, the active ingredient
comprises a volatile
compound. In a further embodiment, the volatile compound comprises a
cyclopropene. In a
further embodiment, the cyclopropene comprises 1-methylcyclopropene (1-MCP).
In another
embodiment, the active ingredient comprises a complex comprising a
cyclopropene and a
molecular encapsulating agent. In a further embodiment, the molecular
encapsulating agent
comprises alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, or
combinations thereof
In another embodiment, the slurry comprises the composition provided herein.
[0016] In another aspect, provided is a method of treating plants or
plant parts comprising
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contacting said plants or plant parts with a slurry comprising an aqueous
medium and a
collection of coated particles, wherein each of the coated particles
comprises,
(a) an active ingredient dispersed in an resin matrix; and
(b) a coating comprising at least one hydrophobic compound.
5 [0017] In one embodiment of the method provided, the active
ingredient comprises a volatile
compound. In a further embodiment, the volatile compound comprises a
cyclopropene. In a
further embodiment, the cyclopropene comprises 1-methylcyclopropene (1-MCP).
In another
embodiment, the active ingredient comprises a complex comprising a
cyclopropene and a
molecular encapsulating agent. In a further embodiment, the molecular
encapsulating agent
comprises alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, or
combinations thereof
In another embodiment, the method uses the composition provided herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 shows representative coated particles of the composition
provided herein,
showing Pickering stabilization structure using hydrophobic particles. HAIP
refers to 1-
methylcyclopropene/alpha-cyclodextrin complex.
[0019] Figure 2 shows representative release profile of 1-
methylcyclopropene (1-MCP).
Figure 2A shows release rate of HA1P in water at ambient temperature. Figure
2B shows
emulsified HA1P and oil in water at different temperature for thirty (30)
minutes.
[0020] Figure 3 shows representative release profile of 1-MCP from
Sample #1 and Sample
#2 upon dilution with water at ambient temperature for different time: Figure
3A at 5-360
minutes; and Figure 3B at 5-4200minutes.
[0021] Figure 4 shows representative release profile of 1-MCP from
Sample #5 upon dilution
with water at ambient temperature for different time: Figure 4A 5-360 minutes;
and Figure 4B at
5-1100minutes.
[0022] Figure 5 shows representative release profile of 1-MCP released from
Sample #3 and
Sample #4 upon dilution with water: Figure 5A at 5-360 minutes at ambient
temperature; Figure
5B at 5-4000 minutes at ambient temperature; and Figure 5C at 30 minutes at 70
C.
[0023] Figure 6 shows representative SEM images of Sample #1 (Figures
6a, 6b, and 6c);
Sample #2 (Figures 6d, 6e, and 6f); and Sample #4 (Figures 6g, 6h, and 6i).
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DETAILED DESCRIPTION OF THE INVENTION
[0024] Provided are methods for preparing compositions comprising: (1)
blending an active
ingredient (for example, 1-MCP complex powder) with resin at the temperature
slightly over the
melting point of the resin; (2) dispersing the blend into an oil medium
containing hydrophobic
particles by shearing and obtain an oil dispersion; (3) consolidating the
resin particles by cooling.
Thus, the active ingredient (for example, 1-MCP complex powder) is imbedded in
the resin
matrix spheres, and the hydrophobic particles, which also serve as Pickering
emulsifier to
stabilize the matrix spheres, form a coating layer around the matrix spheres
to provide protection
against water. Thus, the sphere is composed of the "Pickering" particle and
resin matrix, in
which the active ingredient is imbedded.
[0025] Also provided are compositions prepared using the methods
provided herein. A
representative morphology of the spheres produced by the methods provided is
illustrated in
Figure 1. As the sample is diluted with water, water needs to go through the
hydrophobic
coating layer and penetrate into the resin matrix, interacts with the imbedded
active ingredient
(for example, 1-MCP complex powder), and releases the active ingredient (for
example, 1-MCP)
from the complex. Thus, compared to unprotected (or uncoated) 1-MCP complex
powder, slow
release of 1-MCP can be achieved upon dilution with water. That also allows
uniform delivery
of 1-MCP to plants, permitting effective and consistent use in field
conditions, and offering
significant improvement in regulating plant physiology.
[0026] Suitable oil medium may include mineral oil, which may comprise
light mixtures of
alkanes in the C15 to C40 range, or a distillate of petroleum. Suitable oil
includes, but is not
limited to, mineral oil, light mineral oils, Isopar oil, Unipar oil and other
hydrocarbon oils, edible
oils and mixture thereof
[0027] Suitable polyester resins include polycaprolactone polyols.
Typical molecular weight
may be from 1,000 to 200,000; from 2,000 to 50,000; from 2,000 to 8,000; or
from 2,000 to
4,000. Typically, the polycaprolactone polyols have a melting point from 30 C
to 120 C; from
40 C to 80 C; or from 50 C to 60 C. For example, resins including PCL with
molecular
weight about 120,000 can have a melting point about 60 C. In one embodiment,
this kind of
resin with a 60 C melting point is useful for the subject invention. 1-
methylcyclopropene/alpha-
cyclodextrin complex (HA1P) is known to tolerate temperature about 100 C for
a short duration
(for example four minutes) without significant activity loss. In one
embodiment, process
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temperature is slightly higher than the melting point of the resin and the
process time is less than
twenty minutes.
[0028] Suitable hydrophobic compounds or hydrophobic particles include
hydrophobic silica,
where silica surface may be modified by silane coupling agent or
organosilicon. Primary particle
size may be from about 10 nanometers to several microns.
[0029] Suitable resins are not limited to the pure polymer resin with
the same chemicals
structures or same molecule weight, but can also include blends of several
resins. And resin
category that is suitable use in the present invention includes, but is not
limited to, polyester,
polyether, epoxy resin, isocyanate, ethylene vinyl acetate copolymer, natural
or synthesized wax,
and mixture thereof. But at least one component of the resins has relatively
strong interaction
with HA1P, so that HA1P particles can be detained within the resin matrix. In
one embodiment,
the resin has a melting point below 100 C, and a viscosity below 10,000
centipoises, so that it
can be blended with HA1P powder and dispersed into oil medium easily.
[0030] Hydrophobic particles herein suitable as Pickering emulsifier
include, but not limited
to, silica particles, clay, oxides, polymer particles and mixture thereof. On
the other hand,
conventional surfactants are optional to assist the formation of a stable
suspension of particles in
oil. Suitable surfactants include, for example, anionic surfactants, nonionic
surfactants, and
mixtures thereof Some suitable anionic surfactants include, but not limited
to, sulfates, and the
sulfonates. Some suitable nonionic surfactants include, but not limited to,
ethoxylates of fatty
alcohols, ethoxylates of fatty acids, block copolymer of polyoxyethylene and
polyolefin, and
mixture thereof.
[0031] The step of consolidating particles is suitable for use in the
present invention includes,
but it not limited to, cooling down to ambient temperature. The ratio of the
Pickering particle
powder to the oil may be from about 1:5 to about 1:25; or from about 1:10 to
about 1:24. The
ratio of the HA1P powder to resins may be from about 1:1 to 1:100; or from
about 1:2: to about
1:100. The ratio of the resins to the oil may be from about 2:1 to about
1:100; or from about 1:1
to about 1:100.
[0032] As used herein, the phrase "Polymer" refers to a relatively large
molecule made up of
the reaction products of smaller chemical repeat units. The repeat units (also
called "monomer
units") are residues of monomer molecules. The repeat units may be all
identical or may include
two or more different repeat units. Polymer molecules may have any structure
including, for
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example, linear, branched, star-shaped, crosslinked, and mixtures thereof
Polymer molecular
weights can be measured by standard methods such as, for example, size
exclusion
chromatography (SEC, also called gel permeation chromatography or GPC).
Polymers have
number-average molecular weight (Mn) of greater than 700. "Oligomer" as used
herein is also a
molecule made up of the reaction products of smaller chemical repeat units
called monomer units.
Oligomers have molecular weight of 700 or less.
[0033] Thermoset polymers can be fully crosslinked. Thermoset polymers
cannot be molded
into new shapes by the application of heat and pressure, and thermoset
polymers cannot be
dissolved in any solvent. Polymers that are not thermoset are called
thermoplastic polymers.
[0034] As used herein, a material is water-insoluble if the amount of that
material that can be
dissolved in water at 25 C is 1 gram of material or less per 100 grams of
water.
[0035] As used herein, when reference is made to a collection of powder
particles, the phrase
most or all of the powder particles" means 50% to 100% of the powder
particles, by weight
based on the total weight of the collection of powder particles.
[0036] As used herein, a "solvent compound" is a compound that has boiling
point at one
atmosphere pressure of between 20 C and 200 C and that is liquid at one
atmosphere pressure
over a range of temperatures that includes 20 C to 30 C. A "solvent" can be
a solvent
compound or a mixture of solvents. A non-aqueous solvent can be a solvent that
either contains
no water or that contains water in an amount of 10% or less by weight based on
the weight of the
solvent.
[0037] As used herein, the phrase "aqueous medium" refers to a
composition that is liquid at
C and that contains 75% or more water by weight, based on the weight of the
aqueous
medium. Ingredients that are dissolved in the aqueous medium are considered to
be part of the
aqueous medium, but materials that are not dissolved in the aqueous medium are
not considered
25 to be part of the aqueous medium. An ingredient is "dissolved" in a
liquid if individual
molecules of that ingredient are distributed throughout the liquid and are in
intimate contact with
the molecules of the liquid.
[0038] As used herein, when any ratio is said to be X:1 or higher, that
ratio is meant to be
Y:1, where Y is X or higher. Similarly, when any ratio is said to be R:1 or
lower, that ratio is
meant to be S:1, where S is R or lower.
[0039] As used herein, the "aspect ratio" of a solid particle is the
ratio of the particle's
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longest dimension to that particle's shortest dimension. A particle's longest
dimension is the
length of the longest possible line segment ("segment L") that passes through
the particle's center
of mass and that has each of its end points on the surface of the particle.
That particle's shortest
dimension is the length of the shortest possible line segment ("segment S")
that passes through
the particle's center of mass, that has each of its end points on the surface
of the particle, and that
is perpendicular to segment L. The aspect ratio is the ratio of the length of
segment L to the
length of segment S.
[0040] As used herein, the "diameter" of a particle is the average of
the length of that
particle's segment L and that particle's segment S. It is noted that, when the
particle is spherical,
this definition gives the "diameter" in the usual sense.
[0041] As used herein, when a property of a powder is described as
having a "median" value,
it is contemplated that half of the total volume of powder particles will
consist of particles that
have that property with value above that median value and that half of the
total volume of
powder particles will consist of particles that have property with value below
that median value.
[0042] The practice of the present invention involves the use of one or
more cyclopropene
compound. As used herein, a cyclopropene compound is any compound with the
formula
R3 R4
R1 R2
where each R2, R3 and R4 is independently selected from the group
consisting of H and a
chemical group of the formula:
-(L)n-Z
where n is an integer from 0 to 12. Each L is a bivalent radical. Suitable L
groups include, for
example, radicals containing one or more atoms selected from H, B, C, N, 0, P,
S, Si, or
mixtures thereof The atoms within an L group may be connected to each other by
single bonds,
double bonds, triple bonds, or mixtures thereof. Each L group may be linear,
branched, cyclic,
or a combination thereof. In any one R group (i.e., any one of R2, R3 and
R4) the total
number of heteroatoms (i.e., atoms that are neither H nor C) is from 0 to 6.
Independently, in
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any one R group the total number of non-hydrogen atoms is 50 or less. Each Z
is a monovalent
radical. Each Z is independently selected from the group consisting of
hydrogen, halo, cyano,
nitro, nitroso, azido, chlorate, bromate, iodate, isocyanato, isocyanido,
isothiocyanato,
pentafluorothio, and a chemical group G, wherein G is a 3 to 14 membered ring
system.
5 [0043] The R2, R3, and R4 groups are independently selected
from the suitable groups.
Among the groups that are suitable for use as one or more of
R2, R3, and R4 are, for example,
aliphatic groups, aliphatic-oxy groups, alkylphosphonato groups,
cycloaliphatic groups,
cycloalkylsulfonyl groups, cycloalkylamino groups, heterocyclic groups, aryl
groups, heteroaryl
groups, halogens, silyl groups, other groups, and mixtures and combinations
thereof Groups
10
that are suitable for use as one or more of R2, R3, and R4 may be
substituted or unsubstituted.
[0044] Among the suitable R2, R3, and R4 groups are, for example,
aliphatic groups.
Some suitable aliphatic groups include, for example, alkyl, alkenyl, and
alkynyl groups. Suitable
aliphatic groups may be linear, branched, cyclic, or a combination thereof.
Independently,
suitable aliphatic groups may be substituted or unsubstituted.
[0045] As used herein, a chemical group of interest is said to be
"substituted" if one or more
hydrogen atoms of the chemical group of interest is replaced by a substituent.
[0046] Also among the suitable
R2, R3, and R4 groups are, for example, substituted and
unsubstituted heterocyclyl groups that are connected to the cyclopropene
compound through an
intervening oxy group, amino group, carbonyl group, or sulfonyl group;
examples of such R2,
R3, and R4 groups are heterocyclyloxy, heterocyclylcarbonyl,
diheterocyclylamino, and
diheterocyclylaminosulfonyl.
[0047] Also among the suitable
R2, R3, and R4 groups are, for example, substituted and
unsubstituted heterocyclic groups that are connected to the cyclopropene
compound through an
intervening oxy group, amino group, carbonyl group, sulfonyl group, thioalkyl
group, or
aminosulfonyl group; examples of such R2, R3, and R4 groups are
diheteroarylamino,
heteroarylthioalkyl, and diheteroarylaminosulfonyl.
[0048] Also among the suitable
R2, R3, and R4 groups are, for example, hydrogen, fluor ,
chloro, bromo, iodo, cyano, nitro, nitroso, azido, chlorato, bromato, iodato,
isocyanato,
isocyanido, isothiocyanato, pentafluorothio; acetoxy, carboethoxy, cyanato,
nitrato, nitrito,
perchlorato, allenyl, butylmercapto, diethylphosphonato, dimethylphenylsilyl,
isoquinolyl,
mercapto, naphthyl, phenoxy, phenyl, piperidino, pyridyl, quinolyl,
triethylsilyl, trimethylsilyl;
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and substituted analogs thereof
[0049] As used herein, the chemical group G is a 3 to 14 membered ring
system. Ring
systems suitable as chemical group G may be substituted or unsubstituted; they
may be aromatic
(including, for example, phenyl and napthyl) or aliphatic (including
unsaturated aliphatic,
partially saturated aliphatic, or saturated aliphatic); and they may be
carbocyclic or heterocyclic.
Among heterocyclic G groups, some suitable heteroatoms are, for example,
nitrogen, sulfur,
oxygen, and combinations thereof. Ring systems suitable as chemical group G
may be
monocyclic, bicyclic, tricyclic, polycyclic, spiro, or fused; among suitable
chemical group G ring
systems that are bicyclic, tricyclic, or fused, the various rings in a single
chemical group G may
be all the same type or may be of two or more types (for example, an aromatic
ring may be fused
with an aliphatic ring).
[0050] In one embodiment, one or more of
R2, R3, and R4 is hydrogen or (Ci-Cio) alkyl.
In another embodiment, each of R2, R3, and R4 is hydrogen or (C1-C8) alkyl.
In another
embodiment, each of
R2, R3, and R4 is hydrogen or (C1-C4) alkyl. In another embodiment,
each of R2, R3, and R4 is hydrogen or methyl. In another embodiment, Rl is
(C1-C4) alkyl
and each of R2, R3, and R4 is hydrogen. In another embodiment, Rl is methyl
and each of R2, R3,
and R4 is hydrogen, and the cyclopropene compound is known herein as 1-
methylcyclopropene
or "1-MCP."
[0051] In one embodiment, a cyclopropene compound can be used that has
boiling point at
one atmosphere pressure of 50 C or lower; 25 C or lower; or 15 C or lower. In
another
embodiment, a cyclopropene compound can be used that has boiling point at one
atmosphere
pressure of -100 C or higher; -50 C or higher; -25 C or higher; or 0 C or
higher.
[0052] The composition of the present invention includes at least one
molecular
encapsulating agent. In preferred embodiments, at least one molecular
encapsulating agent
encapsulates one or more cyclopropene compound or a portion of one or more
cyclopropene
compound. A complex that contains a cyclopropene compound molecule or a
portion of a
cyclopropene compound molecule encapsulated in a molecule of a molecular
encapsulating
agent is known herein as a "cyclopropene compound complex."
[0053] In one embodiment, at least one cyclopropene compound complex is
present that is an
inclusion complex. In a further embodiment for such an inclusion complex, the
molecular
encapsulating agent forms a cavity, and the cyclopropene compound or a portion
of the
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cyclopropene compound is located within that cavity.
[0054] In another embodiment for such inclusion complexes, the interior
of the cavity of the
molecular encapsulating agent is substantially apolar or hydrophobic or both,
and the
cyclopropene compound (or the portion of the cyclopropene compound located
within that cavity)
is also substantially apolar or hydrophobic or both. While the present
invention is not limited to
any particular theory or mechanism, it is contemplated that, in such apolar
cyclopropene
compound complexes, van der Waals forces, or hydrophobic interactions, or
both, cause the
cyclopropene compound molecule or portion thereof to remain within the cavity
of the molecular
encapsulating agent.
[0055] The amount of molecular encapsulating agent can usefully be
characterized by the
ratio of moles of molecular encapsulating agent to moles of cyclopropene
compound. In one
embodiment, the ratio of moles of molecular encapsulating agent to moles of
cyclopropene
compound can be 0.1 or larger; 0.2 or larger; 0.5 or larger; or 0.9 or larger.
In another
embodiment, the ratio of moles of molecular encapsulating agent to moles of
cyclopropene
compound can be 10 or lower; 5 or lower; 2 or lower; or 1.5 or lower.
[0056] Suitable molecular encapsulating agents include, for example,
organic and inorganic
molecular encapsulating agents. Suitable organic molecular encapsulating
agents, which include,
for example, substituted cyclodextrins, unsubstituted cyclodextrins, and crown
ethers. Suitable
inorganic molecular encapsulating agents include, for example, zeolites.
Mixtures of suitable
molecular encapsulating agents are also suitable. In one embodiment, the
encapsulating agent is
alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin, or combinations
thereof. In a
further embodiment, alpha-cyclodextrin is used.
[0057] In one embodiment, complex powders may have median particle
diameter of 10
micrometers or less; 7 micrometers or less; or 5 micrometers or less. In
another embodiment,
complex powders may have median particle diameter of 0.1 micrometer or more;
or 0.3
micrometer or more. Median particle diameter may be measured by light
diffraction using a
commercial instrument such as those manufactured, for example, by Horiba Co.
or Malvern
Instruments.
[0058] In another embodiment, complex powders may have median aspect
ratio of 5:1 or
lower; 3:1 or lower; or 2:1 or lower. If a complex powder is obtained that has
undesirably high
median aspect ratio, mechanical means may be used, for example, milling, to
reduce the median
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aspect ratio to a desirable value.
[0059] In one embodiment, suitable resins may have melting point of 55
C or higher; 65 C
or higher; or 70 C or higher. In another embodiment, suitable resins may have
melting point of
100 C or lower; or 90 C or lower.
[0060] Another method of assessing fatty compounds is the temperature of
onset of the
melting point. To determine the onset temperature, the exotherm curve (heat
flow vs.
temperature) produced by the DSC for the melting point transition is observed.
The baseline is
determined, and a corrected heat-flow curve calculated by subtracting the
baseline from the
original heat-flow curve. The maximum heat-flow value of the corrected curve
(RFMAX) is
determined. The onset temperature is the lowest temperature at which the heat-
flow value on the
corrected curve is equal to 0.1*TIFMAX. Suitable resins may have onset
temperature of 45 C or
higher; or 55 C or higher.
[0061] One useful way to characterize the powder composition of the
present invention is the
median particle diameter, which may be 100 micrometers or less; 75 micrometers
or less; 50
micrometers or less; or 25 micrometers or less.
[0062] The composition of the present invention may be used for treating
plants or plant
parts in any way. For example, the composition may be mixed with other
materials or may be
used directly.
[0063] Provided is a method of using the composition of the present
invention for a
formation of an aqueous slurry. An aqueous slurry can be formed when the
composition
provided is mixed with an aqueous medium. To form such a slurry, the aqueous
medium may be
mixed directly with the composition of the present invention. It is expected
that the coated
particles of the composition provided remain intact in the slurry. It is also
contemplated that
most or all of the coated particles will be dispersed in the slurry as
individual particles rather
than as agglomerates thereof. The coated particles may require mechanical
agitation to remain
suspended in the aqueous medium, or they may remain suspended without
agitation.
[0064] The amount of composition provided in the slurry may be
characterized by the
concentration of cyclopropene compound in the slurry. In one embodiment,
suitable slurries
may have cyclopropene compound concentration, in units of milligrams of
cyclopropene
compound per liter of slurry, of 2 or higher; 5 or higher; or 10 or higher. In
another embodiment,
suitable slurries may have cyclopropene compound concentration, in units of
milligrams of
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cyclopropene compound per liter of slurry, of 1000 or lower; 500 or lower; or
200 or lower.
[0065] The amount of water in the aqueous medium used in the slurry may
be, by weight
based on the weight of aqueous medium, 80% or more; 90% or more; or 95% or
more.
[0066] The slurry may optionally contain one or more adjuvants, for
example, one or more
metal complexing agent, one or more surfactant, one or more oil, one or more
alcohol, or
mixtures thereof Examples of metal-complexing agents, if used, include
chelating agents.
Examples of surfactants, if used, include anionic surfactants and silicone
surfactants. Examples
of alcohols, if used, include alkyl alcohols with 4 or fewer carbon atoms.
Oils are compounds
that are liquid at 25 C, are not water, are not surfactants, and are not
alcohols. Examples of oils,
if used, include hydrocarbon oils and silicone oils.
[0067] Also provided is a method of treating plants by bringing the
slurry into contact with
plants or plant parts. Such contacting may be performed in any location,
including inside
enclosed spaces (for example, containers, rooms, or buildings) or outside of
an enclosed space.
In one embodiment, such contacting is performed outside of any enclosed space.
As used herein,
"outside of any enclosed space" means outside of any building or enclosure or
else in a room or
building that is ventilated to outdoor atmosphere. In another embodiment, such
contacting is
performed outside of any building or enclosure. In a further embodiment, such
contacting is
performed in an outdoor field or plot.
[0068] The slurry of the present invention may be brought into contact
with plants or plant
parts by methods known in the art. Examples of methods include dipping plant
parts into the
slurry and applying slurry to plants or plant parts by spraying, foaming,
brushing, or
combinations thereof. Other examples include spraying the slurry onto plants
or plant parts and
dipping plant parts into the slurry. Additional examples include spraying the
slurry onto plants
or plant parts.
[0069] Plants or plant parts may be treated in the practice of the present
invention. One
example is treatment of whole plants; another example is treatment of whole
plants while they
are planted in soil, prior to the harvesting of useful plant parts.
[0070] Any plants that provide useful plant parts may be treated in the
practice of the present
invention. Examples include plants that provide fruits, vegetables, and
grains.
[0071] As used herein, the phrase "plant" includes dicotyledons plants and
monocotyledons
plants. Examples of dicotyledons plants include tobacco, Arabidopsis, soybean,
tomato, papaya,
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canola, sunflower, cotton, alfalfa, potato, grapevine, pigeon pea, pea,
Brassica, chickpea, sugar
beet, rapeseed, watermelon, melon, pepper, peanut, pumpkin, radish, spinach,
squash, broccoli,
cabbage, carrot, cauliflower, celery, Chinese cabbage, cucumber, eggplant, and
lettuce.
Examples of monocotyledons plants include corn, rice, wheat, sugarcane,
barley, rye, sorghum,
5 orchids, bamboo, banana, cattails, lilies, oat, onion, millet, and
triticale.
[0072] As used herein, the phase "plant growth regulator" includes, but
not limited to,
ethylene, cyclopropenes, glyphosate, glufosinate, and 2,4-D. Other suitable
plant growth
regulators have been disclosed in International Patent Application Publication
WO
2008/071714A1, which is incorporated by reference in its entirety.
10 EXAMPLES
Example 1
Sample Preparation
[0073] Steps to make 1-MCP powder dispersion - The samples are prepared
as follow:
(a) Charging air milled HA1P (1-methylcyclopropene/alpha-cyclodextrin complex)
powder and
15 polymer resin into a vessel, then the vessel is placed in a oil bath and
heated to temperature
slightly over melting point of the resin, the HA1P powder is evenly dispersed
into the resin under
shearing, thus a viscous dispersion is obtained;
(b) Adding silica powder into oil, followed by shearing under ambient
temperature to get a
uniform mixture. Then heat the mixture to the temperature slightly over the
melting point of
resin;
(c) Adding HA1P powder dispersion in oil from step (a), into mixture of oil
and silica particles
from step (b). Disperse HAIP powder dispersion in oil from step (a) into
mixture of oil and
silica particles from step (b) by high speed shearing at the temperature
slightly above melting
point of the resin; and
(d) Consolidating the dispersed particles by cooling.
Example 2
Test Methods
[0074] The release of diluted samples is investigated as follow: About
0.2 g sample and 0.04
g of surfactants are charged into a vial of 22 ml and the mixture is blended
evenly by shearing.
Then 2 ml water is added to the vial and milk like emulsion is obtained after
shearing. A series
of diluted samples are prepared using this method. After placing the vials at
ambient
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temperature for certain period of time, the sample can be analyzed by gas
chromatography to
observe concentration variation of 1-MCP and to track and detect the effective
release of 1-MCP.
The heater on the oven is then turned off, with the temperature on the oven
about 40 C, while
ambient temperature was about 22 C. The head space analysis measurement is
taken after a
given time period after the sample is diluted with water. Each vial is sampled
once, that is, a
new vial is used to obtain each data point for time release studies.
[0075] From the measure concentration of 1-MCP in the headspace, the
amount of sample
added to the vial and the theoretical 1-MCP content in the sample, the
fraction of the total
amount of 1-MCP in the vial that resides in the headspace can be calculated
and reported as a
percentage based on the amount of 1-MCP added to the vial.
[0076] The release of 1-MCP from the samples is compared to the release
of 1-MCP from
HAIP powder. For measuring the release of 1-MCP from HAIP, about 20 mg of HAIP
powder
is weighed into a 22 ml headspace vial and 2 ml water is injected. The head
space analysis
measurement is taken under the same conditions described above.
Example 3
Preparation of Sample #1
[0077] Sample #1 is prepared as the following:
[0078] (1) 26.04 g polyester resin is added to a vessel, and the vessel
is heated to the melting
point of the polyester, i.e., 60 C. After all the resin melt, 6.47 g HAIP
powder is charged, and
the mixture is thoroughly mixed by shearing for about ten minutes, then HAIP
powder is evenly
dispersed in the melt resin to obtain viscous dispersion.
[0079] (2) 64.45 g mineral oil and 3.04g silica powder are charged into
a vessel, and then the
mixture is thoroughly mixed by shearing, followed by heating to 60 C.
[0080] (3) HAIP dispersion (1) is blended with Pickering particle
dispersion (2) under high
shearing of about 1000 rpm for about three minutes at about 60 C; the resin
is dispersed into
mineral oil to form spheres wherein HAIP imbedded. Then the dispersion is
cooled down to
ambient temperature.
Example 4
Preparation of Sample #2
[0081] Sample #2 is prepared as the following:
[0082] (1) 28.75 g polyester resin is added to a vessel, and the vessel
is heated to the melting
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point of the polyester, i.e., 60 C. After all the resin melt, 7.19g HA1P
powder is charged, and
the mixture is thoroughly mixed by shearing for about ten minutes, then HA1P
powder is evenly
dispersed in the melt resin to obtain viscous dispersion.
[0083] (2) 60.15g mineral oil and 3.91g silica powder are charged into a
vessel, and then the
mixture is thoroughly mixed by shearing, followed by heating to 60 C.
[0084] (3) HA1P dispersion (1) is blended with Pickering particle
dispersion (2) under high
shearing of about 3400rpm for about three minutes at about 60 C; the resin is
dispersed into
mineral oil to form spheres wherein HA1P imbedded. Then the dispersion is
cooled down to
ambient temperature.
Example 5
Preparation of Sample #3
[0085] Sample #3 is prepared as the following:
[0086] (1) 22.98 g polyester resin is added to a vessel, and the vessel
is heated to the melting
point of the polyester, i.e., 60 C. After all the resin melt, 5.74 g HA1P
powder is charged, and
the mixture is thoroughly mixed by shearing for about ten minutes, then HA1P
powder is evenly
dispersed in the melt resin to obtain viscous dispersion.
[0087] (2) 67.01 g Isopar M and 4.27 g silica powder are charged into a
vessel, and then the
mixture is thoroughly mixed by shearing, followed by heating to 60 C.
[0088] (3) HA1P dispersion (1) is blended with Pickering particle
dispersion (2) under high
shearing of about 3400 rpm for about three minutes at about 60 C; the resin
is dispersed into
Isopar M to form spheres wherein HA1P particles imbedded. Then the dispersion
is cooled down
to ambient temperature.
Example 6
Preparation of Sample #4
[0089] Sample #4 is prepared as the following:
[0090] (1) 23.27 g polyester resin is added to a vessel, and the vessel
is heated to the melting
point of the polyester, i.e., 60 C. After all the resin melt, 5.83 g HA1P
powder is charged, and
the mixture is thoroughly mixed by shearing for about ten minutes, then HA1P
powder is evenly
dispersed in the melt resin to obtain viscous dispersion.
[0091] (2) 65.85 g Isopar M, 4.20 g silica R805 and 0.85 g D17 powder are
charged into a
vessel, and then the mixture is thoroughly mixed by shearing, followed by
heating to 60 C.
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[0092] (3) HAIP dispersion (1) is blended with Pickering particle
dispersion (2) under high
shearing of about 3400 rpm for about three minutes at about 60 C; the resin
is dispersed into
Isopar M to form spheres wherein HAIP particles imbedded. Then the dispersion
is cooled down
to ambient temperature.
Example 7
Preparation of Sample #5
[0093] Sample #5 is prepared as the following:
[0094] (1) 22.88 g polyester resin is added to a vessel, and the vessel
is heated to the melting
point of the polyester, i.e., 60 C. After all the resin melt, 5.72 g HAIP
powder is charged, and
the mixture is thoroughly mixed under shearing for about ten minutes, then
HAIP powder is
evenly dispersed in the melt resin to obtain viscous dispersion.
[0095] (2) 67.37 g mineral oil, 0.81 g Unithox 720, 1.88 g Unithox 750
and 1.34 g SDBS are
charged into a vessel, and then the mixture is heated to about 110 C. After
that, the mixture is
thoroughly mixed by shearing, then cool down to 60 C to obtain surfactant
dispersion.
[0096] (3) HAIP dispersion (1) is blended with surfactant dispersion (2)
under high shearing
for about three minutes at about 60 C; the resin is dispersed into mineral
oil to form particles
wherein HAIP particles imbedded. Then the dispersion is cooled down to room
temperature.
Example 8
Formulation
[0097] Formulations of samples are summarized in Table 1.
Ingredients Sample #1 Sample #2 Sample #3 Sample #4 Sample #5
Comparative
sample 1
HAIP powder a 6.47g 7.19g 5.74g 5.83g 5.72g Only this
Polymer resin 26.04g 28.75g 22.98g 23.27g 22.88g powder
Oil b 64.45g 60.15g 67.01g 65.85g 67.37g
Silica powder R805 3.04 3.91 4.27g 4.20g
Silica powder D17 / I I 0.85g
Unithox 720 I I I I 0.81g
Unithox 750 I I I I 1.88g
SDBS I I I I 1.34g
Total weight 100.00g 100.00g 100.00g 100.00g 100.00g
a. HAIP is 1-MCP complex powder contains about 4.5% 1-methylcyclopropene.
b. For Sample #1, #2 and #5, the oil used is mineral oil; for Sample #3 and
#4, the oil used is Isopar M.
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Example 9
Comparative Samples
[0098] Comparative samples are prepared as the following:
[0099] (1) HA1P +water system: 20 mg HA1P powder is sealed in a vial,
and 2 ml water is
injected, 1-MCP concentration in head space is analyzed by gas chromatography.
Figure 2A
shows the release profile of 1-MCP from HA1P powder upon contact with water.
As shown in
Figure 2A, at ambient temperature, 1-MCP is released and diffused completely
in about ten
minutes from HA1P upon contact with water.
[00100] HAIP + oil + water system: 20 mg HA1P powder is first blended with 250
mg oil
under shearing, then the mixture and surfactant are sealed in a vial, and
water is injected, then the
vial is shaken to obtain a uniform emulsion. After that, the diluted samples
are hold at different
temperatures (22, 50, 55, 60, 65 and 70 C) for 30 minutes. 1-MCP
concentration in head space
is analyzed by gas chromatography at corresponding temperatures. Figure 2B
shows the release
profile of 1-MCP. As shown in Figure 2B, after emulsified samples are hold at
22, 50, 55, 60, 65
and 70 C for 30 minutes, released 1-MCP into head space are 70%, 80%, 84%,
91%, 95% and
100%, respectively. That is, the release ratios increase with the increase of
temperature, and
under current conditions only 70% 1-MCP released into head space at ambient
temperature, and
even if hold the sample at this temperature for longer time the release ratio
is still ¨70%.
Example 10
Release Profiles of Test Samples
[00101] Figure 3A shows a representative release profile of 1-MCP from the
diluted Sample
#1 and Sample #2. As shown in Figure 3A, initial release ratio is ¨4% for
Sample #1 and ¨10%
for Sample #2; within 300 minutes there are no big changes in release ratio,
less than 10% for
Sample #1 and about 20% for Sample #2. For longer time, as shown in Figure 3B,
the release
ratio increase over time, 1-MCP is released continually even after contact
with water for about
4,000 minutes.
[00102] Figure 4A shows a representative release profile of 1-MCP from the
diluted Sample
#5. As shown in Figure 4A, initial release ratio is ¨25%; within 5-300 minutes
release ratio
increased from ¨25% to ¨41%. For longer time, as shown in Figure 4B, the
release ratio
increase over time, 1-MCP is released continually even after contact with
water for about 1,100
minutes.
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[00103] Figures 5A and 5B show representative release profiles of 1-MCP from
the diluted
Sample #3 and Sample #4. As shown in Figures 5A and 5B, within 240 minutes the
release ratio
for both samples is about 23% and there are no big changes in release ratio.
For longer time, as
shown in Figure 5B, the release ratio increase over time, 1-MCP is released
continually even
5 after contact with water for about 4,000 minutes. As hold the diluted
samples at 70 C for 30
minutes, the release ratio is about 88.7% for Sample #3, 85.1% for Sample #4,
as shown in
Figure 5C.
[00104] In view of the above, the matrix encapsulated composition of the
present invention is
convenient for use in liquid form. Compared to HAIP powder form, HA1P
particles are double
10 protected by resin matrix spheres and hydrophobic Pickering particles
layer around spheres
according to the composition provided. As the sample is diluted with water,
water needs to go
through the hydrophobic particle layer and penetrate into the resin matrix,
interacts with the
imbedded HA1P particles, and releases 1-MCP from HA1P. Low initial release
ratio can be
achieved within several hours after dilution, slow release of 1-MCP can be
achieved for longer
15 time and give longer application time; and also this allows uniform
delivery of 1-MCP upon
water dilution, permitting effective and consistent use in field conditions.
Compared to oil
droplets encapsulation formulation in which 1-MCP content is very low (less
than 5Oppm) since
1-MCP gas is used, 1-MCP content can increase to more than 200,000 ppm since
HA1P powder
can be used to conduct the encapsulation in this invention.
20 Example 11
SEM Images of Test Samples
[00105] SEM image of the dispersions can be obtained for test samples provided
herein. As
shown in Figure 6, the particle sizes of Sample #1, Sample #2 and Sample #4
are about 30-250
microns, 20-100 microns, and 20-120 microns, respectively. Furthermore, for
all these samples
the matrix spheres are covered by hydrophobic silica particles. For 1-MCP
release study, the
sample and some surfactants are sealed in a vial, and water is injected, then
the vial is shaken to
obtain a uniform emulsion. The head space analysis measurement is taken after
a given time
period after dilution.
