U.S. patent application number 11/238376 was filed with the patent office on 2007-03-29 for granular controlled release agrochemical compositions and process for the preparation thereof.
This patent application is currently assigned to OMS Investments, Inc.. Invention is credited to Petra Leonarda Hendrica Lunde-Vannuys, Johannes Gijsbertus Antonius Terlingen, Lonneke Jacoba van Boxtel-Verhoeven.
Application Number | 20070072775 11/238376 |
Document ID | / |
Family ID | 37894860 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070072775 |
Kind Code |
A1 |
van Boxtel-Verhoeven; Lonneke
Jacoba ; et al. |
March 29, 2007 |
Granular controlled release agrochemical compositions and process
for the preparation thereof
Abstract
A granular agrochemical composition is disclosed including a
granular core material having a water soluble portion with a first
coating layer applied on the surface of the core material and a
second coating layer applied on the surface of the first coating
layer. The first coating layer includes a wax composition having a
biologically active ingredient incorporated therein and the second
coating layer includes a polymeric composition. The granular
agrochemical composition exhibits a controlled rate of release of
the biologically active ingredient therefrom over a period greater
than about 30 days from the date of initial exposure of the
granular composition to moisture whereby essentially all of the
biologically active ingredient incorporated in the wax material of
the first coating layer is released from the granular composition
before the water soluble portion of the granular core material is
released from the granular composition.
Inventors: |
van Boxtel-Verhoeven; Lonneke
Jacoba; (Born, NL) ; Terlingen; Johannes Gijsbertus
Antonius; (Landgraaf, NL) ; Lunde-Vannuys; Petra
Leonarda Hendrica; (Heerlen, NL) |
Correspondence
Address: |
WELSH & KATZ, LTD
120 S RIVERSIDE PLAZA
22ND FLOOR
CHICAGO
IL
60606
US
|
Assignee: |
OMS Investments, Inc.
Los Angeles
CA
|
Family ID: |
37894860 |
Appl. No.: |
11/238376 |
Filed: |
September 29, 2005 |
Current U.S.
Class: |
504/367 ;
424/405; 71/64.03 |
Current CPC
Class: |
A01N 57/12 20130101;
C05G 5/38 20200201; C05G 5/38 20200201; A01N 25/14 20130101; C05G
5/37 20200201; C05G 5/37 20200201; Y10S 514/952 20130101; A01N
25/12 20130101; C05G 5/37 20200201; A01N 25/12 20130101; Y10S
514/951 20130101; C05G 3/60 20200201; A01N 51/00 20130101 |
Class at
Publication: |
504/367 ;
424/405; 071/064.03 |
International
Class: |
A01N 25/12 20060101
A01N025/12; A01N 25/00 20060101 A01N025/00 |
Claims
1. A granular agrochemical composition comprising: a) a granular
core material including a water soluble portion; b) a first coating
layer comprising a wax composition having a biologically active
ingredient incorporated therein applied on the surface of the core
material; and c) a second coating layer comprising a polymeric
composition applied on the surface of the first coating layer; d)
said granular composition exhibiting a controlled rate of release
of the biologically active ingredient therefrom over a period
greater than about 30 days from the date of initial exposure of the
granular composition to moisture whereby essentially all of the
biologically active ingredient incorporated in the wax material of
the first coating layer is released from the granular composition
before the water soluble portion of the granular core material is
released from the granular composition.
2. The granular agrochemical composition of claim 1 wherein the
water soluble portion of the core material generates sufficient
osmotic pressure within the granular composition to cause the
biologically active ingredient in the first coating layer to be
released therefrom when the composition is contacted with
moisture.
3. The granular agrochemical composition of claim 2 wherein the
second coating layer is structured to withstand the osmotic
pressure generated by the core material.
4. The granular agrochemical composition of claim 1 wherein the
water soluble core material is a fertilizer.
5. The granular agrochemical composition of claim 4 wherein the
fertilizer is selected from the group consisting of ammonium
sulfate, potassium nitrate, potassium sulfate, urea, ammonium
nitrate, monopotassium sulfate, ammonium phosphate,
super-phosphate, calcium phosphates, potassium phosphate, potassium
chloride, magnesium oxide, magnesium sulfate, dolomite and mixture
thereof.
6. The granular agrochemical composition of claim 4 wherein the
core material includes at least one secondary nutrient or
micronutrient.
7. The granular agrochemical composition of claim 6 wherein the
secondary nutrient is selected from the group consisting of
calcium, magnesium, sulfur and mixtures thereof.
8. The granular agrochemical composition of claim 6 wherein the
micronutrient is selected from the group consisting of chelated or
non-chelated iron, copper, zinc, manganese, boron, cobalt,
chlorine, sodium, molybdenum and mixtures thereof.
9. The granular agrochemical composition of claim 1 wherein the
core material includes a non-active material.
10. The granular agrochemical composition of claim 1 wherein the
core material has a solubility of about 2 to about 800 g/l.
11. The granular agrochemical composition of claim 1 wherein the
core material is shaped as a granule having a diameter of about
0.35 to about 6 mm.
12. The granular agrochemical composition of claim 1 wherein the
biologically active ingredient is selected from the group
consisting of pesticides, insecticides, herbicides, fungicides,
fertilizers, growth regulators, pheromones, biostimulants,
acaricides, miticides, nematocides and mixtures thereof.
13. The granular agrochemical composition of claim 1 wherein the
wax composition has a melting point of greater than 50.degree.
C.
14. The granular agrochemical composition of claim 13 wherein the
wax composition is hydrophobic.
15. The granular agrochemical composition of claim 13 wherein the
wax composition is hydrophilic.
16. The granular agrochemical composition of claim 1 wherein the
wax composition is water soluble.
17. The granular agrochemical composition of claim 1 wherein the
polymeric composition is a (semi-)water permeable material selected
from the group consisting of thermosetting resins, thermoplastic
resins, latex polymers and mixtures thereof.
18. The granular agrochemical composition of claim 1 wherein
greater than about 90% of the biologically active ingredient
incorporated in the wax composition of the first layer is released
from the granular composition while a residual amount of the water
soluble portion of the core material remains in the granular
composition.
19. A process for preparing a granular agrochemical composition
exhibiting a controlled rate of release of a biologically active
ingredient incorporated in the granular composition over a period
greater than about 30 days from the date of initial exposure of the
granular composition to moisture whereby essentially all of the
biologically active ingredient is released from the granular
composition while at least a residual amount of a core material
remains in the granular composition comprising: a) providing a
granular core material; b) applying a first coating layer
comprising a wax composition having a biologically active
ingredient incorporated therein on the surface of the core
material; and c) applying a second coating layer comprising a
polymeric composition on the surface of the first coating
layer.
20. The process of claim 19 wherein the core material is at least
partially water soluble whereby a sufficient osmotic pressure is
generated within the granular composition to cause the biologically
active ingredient in the first coating to be released therefrom
when the core material is contacted with water.
21. The process of claim 20 wherein the second coating layer is
structured to withstand the osmotic pressure generated by the core
material.
22. The process of claim 20 wherein the water soluble core material
is a fertilizer.
23. The process of claim 22 wherein the fertilizer is selected from
the group consisting of ammonium sulfate, potassium nitrate,
potassium sulfate, urea, ammonium nitrate, monopotassium sulfate,
ammonium phosphate, super-phosphate, calcium phosphates, potassium
phosphate, potassium chloride, magnesium oxide, magnesium sulfate,
dolomite and mixture thereof.
24. The process of claim 22 wherein the core material includes at
least one secondary nutrient or micronutrient.
25. The process of claim 24 wherein the secondary nutrient is
selected from the group consisting of calcium, magnesium, sulfur
and mixtures thereof.
26. The process of claim 25 wherein the micronutrient is selected
from the group consisting of chelated or non-chelated iron, copper,
zinc, manganese, boron, cobalt, chlorine, sodium, molybdenum and
mixtures thereof.
27. The process of claim 19 wherein the core material includes a
non-active material.
28. The process of claim 19 wherein the core material has a
solubility of about 2 to about 800 g/l.
29. The process of claim 19 wherein the core material is shaped as
a granule having a diameter of about 0.35 to about 6 mm.
30. The process of claim 19 wherein the biologically active
ingredient is selected from the group consisting of pesticides,
insecticides, herbicides, fungicides, fertilizers, growth
regulators, pheromones, biostimulants, acaricides, miticides,
nematocides and mixtures thereof.
31. The process of claim 19 wherein the wax composition has a
melting point of greater than 50.degree. C.
32. The process of claim 31 wherein the wax composition is
hydrophobic.
33. The process of claim 31 wherein the wax composition is
hydrophilic.
34. The process of claim 19 wherein the wax composition is water
soluble.
35. The process of claim 19 wherein the polymeric composition is a
(semi-)water permeable material selected from the group consisting
of thermosetting resins, thermoplastic resins, latex polymers and
mixtures thereof.
36. The process of claim 19 wherein greater than about 90% of the
biologically active ingredient incorporated in the wax composition
of the first layer is released from the granular composition while
a residual amount of the core material remains in the granular
composition.
37. An agrochemical composition which exhibits controlled release
of a biologically active ingredient over a period greater than
about 30 days from the date of initial exposure of the composition
to moisture at a release rate such that essentially all of the
biologically active ingredient is released from the composition
while at least a residual amount of a water soluble portion of a
core material remains in the granular composition, the composition
comprising a granular core material having a first coating layer
comprising a wax material having a plant protection product
incorporated therein applied on the core material and a second
polymeric coating layer applied over the first coating layer.
38. The granular agrochemical composition of claim 37 wherein the
core material is at least partially water soluble whereby a
sufficient osmotic pressure is generated within the granular
composition to cause the biologically active ingredient in the
first coating to be released therefrom when the agrochemical
composition is contacted with water.
39. The granular agrochemical composition of claim 37 wherein the
second coating layer is structured to withstand the osmotic
pressure generated by the core material.
40. The granular agrochemical composition of claim 37 wherein the
water soluble portion of the core material is a fertilizer.
41. The granular agrochemical composition of claim 37 wherein the
biologically active ingredient is selected from the group
consisting of pesticides, insecticides, herbicides, fungicides,
fertilizers, growth regulators, pheromones, biostimulants,
acaricides, miticides, nematocides and mixtures thereof.
42. The granular agrochemical composition of claim 37 wherein the
wax composition has a melting point of greater than 50.degree.
C.
43. The granular agrochemical composition of claim 42 wherein the
wax composition is hydrophobic.
44. The granular agrochemical composition of claim 42 wherein the
wax composition is hydrophilic.
45. The granular agrochemical composition of claim 37 wherein the
polymeric composition is a (semi-)water permeable material selected
from the group consisting of thermosetting resins, thermoplastic
resins, latex polymers and mixtures thereof.
46. The granular agrochemical composition of claim 37 wherein
greater than about 90% of the biologically active ingredient
incorporated in the wax composition of the first layer is released
from the granular composition while a residual amount of the core
material remains in the granular composition.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to granular agrochemical
compositions and to processes for producing such compositions. More
particularly, it relates to controlled release agrochemical
compositions having a first coating layer comprising a wax
composition with a biologically active ingredient incorporated
therein applied on the surface of a core material and having a
second coating layer comprising a polymeric composition applied on
the surface of the first coating layer and to processes for
preparing such compositions.
[0003] 2. Description of Related Art
[0004] Agrochemicals as referred to herein include biologically
active ingredients/plant protection products such as insecticides,
herbicides, fertilizers, growth regulators, pheromones,
biostimulants, acaricides, miticides, nematocides, fungicides and
the like. Such agrochemicals are well known and are in common usage
for controlling pests and diseases and for promoting plant growth
in agriculture. In practice, it is important to make a sufficient
amount of such agrochemical or active ingredient available to the
biological system in order to control pests or disease or to
promote growth. Too much active ingredient, however, is inefficient
and not desired because of environmental and economic concerns.
Furthermore, higher amounts of active ingredient lead to increased
risks of leaching to ground water or surface water. Higher amounts
can also lead to phytotoxicity for the crop. Insufficient levels of
active ingredients results in lack of control of the pest and
increase the risk of resistance.
[0005] Thus, it is generally known that it is important to deliver
the correct amount of active ingredient to the crop for control of
the pest or disease and to promote growth over a given period of
time. However, multiple applications of active ingredients becomes
labor and cost intensive. With conventional applications of liquid
or powder formulations, relatively high amounts of active
ingredients are applied several times to assure control of pests
over a longer period of time, typically 3-6 times for seasonal
control, and users are exposed to the active ingredients during
each application, which is undesirable.
[0006] When active ingredients are applied in granular form instead
of by spraying or dusting, the risk of exposure to the active
ingredient is more limited. After application of a granular
pesticide the active ingredient is released to the soil under the
influence of water. The release rate varies depending on the
formulation of the granule. The granules can be divided into two
categories. The first category releases the active ingredient
quickly and has to be applied several times during the season. The
second category releases the active ingredient over a period of
time and provides control of pests during an extended period up to
a whole season. To control pests over a longer period of time the
concentration of active ingredient must be above the minimal
effective level during the whole period. To maintain this effective
concentration, the loss of active ingredient via leaching,
degradation and uptake by the plant must be compensated. The rate
of degradation and leaching depends on the active ingredient and
the amount that is lost, is directly related to the concentration
of the active ingredient in the soil. Thus high concentrations
result in relatively more degradation and leaching.
[0007] In general, known controlled release granular active
ingredients suffer serious limitations. They generally do not
deliver the active ingredient to the biological system for periods
of greater than about 30 days from the date of initial exposure to
moisture and/or they do not completely release the active
ingredient. The practical limitations of systems that release the
active ingredient in less than about 30 days are that they must be
periodically reapplied during the growing season resulting in
additional cost. The limitations of systems which do not completely
release the active ingredient in the desired period of time are
related to efficiency. More active ingredient must be used to
compensate for the portion which does not release effectively. This
incurs additional cost to the user. Furthermore, the residual,
unreleased active ingredient poses an environmental threat and can
lead to biological resistance in the pest. Active ingredient that
is not released cannot be used for controlling a pest or disease
and will give undesirable residues of active ingredient. In the
long run this can lead to build up of chemicals in soil and this is
even less desirable. Without residues after the release period soil
can be recycled without any risk for succeeding crop. The use of
lower amounts of active ingredients and high efficiency are
especially desired from an economical and environmental point of
view.
[0008] A number of approaches have been taken heretofore in
production of controlled release granular agrochemical
compositions. For example, EP Patent 079668 discloses an
encapsulated pesticide product wherein a granular core is coated
with a pesticide and then a plurality of layers of a membrane like
coating are applied over the pesticidal coat to enable controlled
release of such pesticide over a period of time upon contact with
water. However, the products disclosed in EP Patent 079668 are
structurally distinct from the products of the present invention
and, accordingly, disadvantageously fail to exhibit a controlled
rate of release of the pesticide over a period greater than about
30 days from the date of initial exposure of the product to
moisture in a manner such that essentially all of the pesticide
coated on the core is released from the granular composition before
the water soluble portion of the core material is released from the
product as is achieved with the compositions of the present
invention.
[0009] U.S. Pat. No. 6,682,751 discloses a granular pesticide
comprising a core material coated with an inner polymer membrane
formed in-situ on the core material with a pesticide applied to the
inner polymer membrane and an outer controlled release polymer
membrane formed in situ on the pesticide to permit controlled
release. The pesticide may be incorporated in several "sandwich"
layers. Again, the products of U.S. Pat. No. 6,682,751, are
structurally different from the products of the present invention
and fail to exhibit a controlled rate of release of the pesticide
over a period greater than about 30 days from the date of initial
exposure of the product to moisture in a manner such that
essentially all of the pesticide coated on the core is released
from the granular composition before the water soluble portion of
the core material is released from the product.
[0010] U.S. Pat. No. 6,080,221 discloses the coating of porous
surfaces of fertilizer particles with tenacious pesticide-resin
solids to form attrition resistant fertilizer-pesticide combination
particles. In this disclosure, the pesticide is dispersed in a
resinoid matrix, which is subsequently bonded onto and into the
fertilizer surface. U.S. Pat. No. 4,971,796 describes another slow
release granular product in which the pesticide is matrixed into
the coating. The granule comprises one layer of proteinacious
material or more layers of proteinacious material with intermediate
spacing layers. The active ingredient is in the proteinacious layer
and is released when this layer degrades. The release rate is
changed by varying the cross linking or the thickness of the layer.
The products of U.S. Pat. No. 6,080,221 and U.S. Pat. No. 4,971,796
fail to exhibit a controlled rate of release of the pesticide over
a period greater than about 30 days from the date of initial
exposure of the product to moisture in a manner such that
essentially all of the pesticide coated on the core is released
from the granular composition before the core material is released
from the product.
[0011] U.S. Pat. No. 6,187,074 and U.S. Pat. No. 6,309,439 disclose
a fertilizer coated with a carboxyl-carrying ethylene copolymer,
the carboxyl-carrying ethylene copolymer being composed of 75%-90%
by weight ethylene and from 10%-25% by weight of an
alpha-olefinically unsaturated C3-C8 carboxylic acid. The coated
fertilizer particles specifically do not contain any crop
protection chemicals. Thus, the products disclosed in these patents
fail to exhibit a controlled rate of release of the pesticide over
a period greater than about 30 days from the date of initial
exposure of the product to moisture in a manner such that
essentially all of the pesticide coated on the core is released
from the granular composition before the core material is released
from the product.
[0012] U.S. Pat. No. 6,693,063 discloses products that are
structurally distinct from the present compositions teaching wax
microcapsules and wax dispersion of pesticides in the absence of a
water soluble core material. Other encapsulated pesticides which do
not include water soluble core materials are disclosed in Japanese
Examined Patent Publication JP-B 5002/1989, JP-A 9304/1994 and JP-A
72805/1994.
[0013] Other pesticides displaying matrix release systems are
disclosed in. U.S. Pat. No. 4,435,383 wherein solid controlled
release pesticidal products are formed comprising an active
ingredient incorporated in a homogeneous combination with a polymer
by melting the polymer and mixing it with the active ingredient.
During this process additional cross-linking agent are added.
Another matrix based pesticide is disclosed in U.S. Pat. No.
5,516,520 wherein a pesticidally active ingredient is encapsulated
in a starch-borax-urea matrix. The slow release from this matrix is
limited to oil-soluble pesticides. The release rate is changed by
varying the amount of urea.
[0014] EP Patent 0755370 discloses other matrix release products
which are mixtures of a nitromethylene or related substances with
fertilizers and glue. EP Patent 1063215 describes briquettes that
slowly release active ingredients. The slow release is obtained via
absorption or adsorption of the active ingredient onto solids with
high surface area.
[0015] The matrix systems all demonstrate release mechanisms
wherein the release of active ingredients from the matrix systems
is via desorption from an absorped state or by diffusion and not by
an osmotic (pump) release mechanism as employed herein. The release
rate of such matrix systems depends on the concentration of the
active ingredient in the system. Thus, the release rate of such
granules decreases over time resulting in initial fast release of
active ingredients which provides high amounts of active ingredient
in the soil at the start, and a slow release at the end.
[0016] Other types of agrochemical products that can release an
active ingredient over a period of time are biodegradable systems
such as those disclosed in U.S. Pat. No. 4,062,855 wherein active
ingredients are incorporated into a polymer that are released via
biodegradation. U.S. Pat. No. 4,267,280 describes a product that
has a biodegradable polymer system that contains the pesticide. It
releases the pesticide depending on environmental conditions via
hydrolyses or depolymerization.
[0017] A disadvantage of these biodegradable products is that the
release of active ingredient depends on the speed of degradation of
the polymer and this degradation depends on the activity of ambient
microorganisms. The activity of the microorganisms can vary greatly
depending on the soil type and local environmental conditions,
types of microbes, pH, temperature, moisture the like. Thus, the
release rate of active ingredients varies and it is difficult to
match the release precisely with the minimal required active
ingredient concentrations.
[0018] Other coated granular pesticidal compositions are disclosed
in International Patent Publication WO 02/05641 wherein a
pesticidal composition is disclosed that can slowly release an
active ingredient. That publication discloses the preparation of
several granular materials with different numbers of coating layers
or properties of the coating layers. Each of the granular materials
has its own release profile. By blending the different granules
they can obtain the desired release pattern of the product. The
variation of release is purely based on coating properties and not
on solubility of components in the formulation.
[0019] EP Patent 0966882 discloses a controlled release granular
product wherein only single granules exhibit a delay of release
after which the pesticide is released. Thus, after a period of
time, a particular granule breaks open and delivers a portion of
active ingredient to the environment. The release over a period of
time is established by combining multiple `delayed release`
granules, which all have different delay times. The granules
themselves do not exhibit controlled release properties, only a
delayed release.
[0020] EP Patent 1148107 discloses a coating procedure for granules
with a low content of volatile substances. This coating procedure
ensures that the release function of the granules does not change
in two weeks time.
[0021] Another example of formulations of this general type is
disclosed in International Patent Publication WO 99/07654
comprising encapsulated fertilizers with a polymeric envelope that
contains a hormone (e.g. an auxin or cytokinine). The hormone is
mixed with a monomer that form a polymeric envelope. Again, the
products disclosed in this reference do not exhibit a controlled
rate of release of the pesticide over a period greater than about
30 days from the date of initial exposure of the product to
moisture in a manner such that essentially all of the pesticide
coated on the core is released from the granular composition before
the core material is released from the product.
[0022] In view of the benefits that can be derived from
agrochemical compositions that provide controlled release of active
ingredients including efficiency and economy of use of the active
ingredients, the reduced environmental impact achieved, the ability
to employ a single application of the composition for extended
control of pests and diseases, reduction in user exposure to the
compositions, it is clear that new, more technically advanced
agrochemical products would be highly desirable. In particular, a
desired objective is to provide agrochemical compositions that
provide extended useful life with essentially complete release of
an active ingredient occurring over a periods of greater than about
30 days from the date of initial exposure to moisture.
[0023] Thus, prior art agrochemical compositions have fallen short
in providing desired functionality and the present invention is
intended to overcome such problem by providing compositions which
functionally demonstrate a controlled rate of release of the active
ingredient over a period of time greater than about 30 days from
the date of initial exposure of the compositions to moisture in a
manner such that essentially all of the active ingredient coated on
the core is released from the granular composition before the core
material is released from the product.
BRIEF SUMMARY OF THE INVENTION
[0024] The present invention relates to granular agrochemical
compositions which exhibit functionality wherein essentially
complete release of the active ingredients occurs over a period of
time greater than about 30 days. These granular compositions
comprise a granular core material which, preferably, is at least
partially water soluble, coated with a first coating layer
comprising a wax material having a biologically active plant
protection product or active ingredient incorporated therein and
having a second coating layer comprising a polymeric composition
applied on the surface of the first coating layer.
[0025] The present invention involves the development of a new
system for release of active ingredients, such as herbicides,
growth regulators, pheromones, bactericides, insecticides,
acaricides and fungicides and the like, over a defined period of
time with high efficiency.
[0026] In a preferred embodiment, the granular agrochemical
composition of the present invention exhibit a controlled rate of
release of the biologically active ingredient therefrom over a
period greater than about 30 days from the date of initial exposure
of the granular composition to moisture whereby essentially all of
the biologically active ingredient incorporated in the wax material
of the first coating layer is released from the granular
composition while at least a residual amount of the core material
remains in the granular composition. In this regard, it has been
found that the release rate of the compositions can be influenced
by changing the coating properties, the solubility of the
core-material and by adjusting various others of the product
constituents.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0027] FIG. 1 illustrates the release rate of a granular
agrochemical composition of the present invention.
[0028] FIG. 2 illustrates the release rate of another embodiment of
the granular agrochemical compositions of the present
invention.
[0029] FIG. 3 illustrates the release rate of a another embodiment
of the granular agrochemical compositions of the present
invention.
[0030] FIG. 4 illustrates the release rate of another embodiment of
the granular agrochemical compositions of the present
invention.
[0031] FIG. 5 illustrates the release rate of another embodiment of
the granular agrochemical compositions of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The products of the present invention comprise granular
agrochemical compositions including a granular core material having
a first coating layer applied on the surface of the core material
and a second coating layer applied over the surface of the first
coating layer. The first coating layer comprises a wax material
having a plant protection product incorporated therein and the
second coating layer comprising a polymeric composition.
[0033] The granular composition of this invention exhibit a
controlled rate of release of a plant protection product therefrom
over a period greater than about 30 days from the date of initial
exposure of the granular composition to moisture, preferably up to
about 104 weeks after initial exposure to moisture, whereby
essentially all of the plant protection product incorporated in the
wax material of the first layer is released from the granular
composition while at least a residual amount of the water soluble
core material remains in the granular composition and methods to
make such a granular agrochemical composition.
[0034] Thus, the present compositions enable lower application
rates for the same period of control because the plant protection
products is essentially completely released at a control rate over
a period of greater than 30 days, preferably up to about 104 weeks,
from the date of initial exposure to water. The products of this
invention have a high efficiency. This means that essentially all
of the active ingredient, preferably greater than 90% of the
initial weight of the active ingredient in the wax coating layer is
released to the environment before the water soluble content of the
core material is completely depleted.
[0035] The process for preparing the granular compositions of the
present invention which exhibit essentially complete release of the
active ingredient over a period greater than about 30 days,
preferably comprises coating a core material with a first coating
layer comprising a wax material having a biologically active
ingredient incorporated therein and applying a second coating layer
comprising a polymeric composition applied over the surface of the
first coating layer.
[0036] Most preferably, the core material is at least partially
water soluble ensuring transport of water to the granule through
the first and second coating layers via osmosis. The "osmotic"
transport of the ingredients occurs as a result of the pumping of
water into and a solution out of the granule and continues until
all core material has been released. Accordingly, once dissolved,
the water dissolvable core material as well as the biologically
active ingredient in the first coating layer are transported out of
the granule.
[0037] Exemplary of suitable core materials for use herein are
fertilizers such as ammonium sulfate, potassium nitrate, potassium
sulfate, urea, ammonium nitrate, monopotassium sulfate, ammonium
phosphate, super-phosphate, calcium phosphates, potassium
phosphate, potassium chloride, magnesium oxide, magnesium sulfate,
dolomite and the like or any fertilizers obtained from compounding
a mixture of these fertilizers. Also, non-active materials such as
sugar and other granular materials may be employed as the core
material herein, if desired.
[0038] In a preferred embodiment of this invention, the core
materials comprise at least one secondary nutrient and/or
micronutrient. Suitable secondary nutrients include calcium,
magnesium, sulfur and mixtures thereof. Suitable micronutrients, in
chelated or non-chelated form, include iron copper, zinc,
manganese, boron, cobalt, chlorine, sodium, molybdenum and mixtures
thereof.
[0039] With regard to the wax composition to be employed to form
the first coating layer, in a most preferred embodiment of this
invention, the wax should be water soluble to facilitate an even
better dissolution of the active ingredient in the coating
layer.
[0040] The granular agrochemical composition of the present
invention exhibits a controlled rate of release of a plant
protection product (active ingredient) therefrom over a period
greater than about 30 days from the date of initial exposure of the
granular composition to moisture whereby essentially all of the
plant protection product incorporated in the wax material of the
first layer is released from the granular composition while at
least a residual amount of the water soluble core material remains
in the granular composition.
[0041] Exemplary, of suitable biologically active ingredients for
use herein are pesticides, insecticides, herbicides, fungicides,
fertilizers, growth regulators, pheromones, biostimulants,
acaricides, miticides, nematocides and mixtures thereof.
[0042] For example, one or more suitable herbicides for use herein
include dichlorophenoxyacetic acid, dichloropicolinic acid,
dichloro-o-anisic acid, diquation, phosphonomethyl)glycine,
isopropyl-4-methyl-5-oxo-2-imidazolin-2-YL)-nicotinic acid, methyl
2-(((((4-methoxy-6-methyl-1,3,5-triazin-2-YL)amino)carbonyl)amino)sulfony-
l)benzoate,
butyl-4-(2,4-dichloro-5-isopropoxyphenyl-delta2-1,3,4-oxadiazoline-5-one
(Note: delta2=delta superscript 2),
ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine, ehtyl
2-chloro-5-4-chloro-(5-difluoromethoxy)-1-methyl-1H-pyrazol-3-YLY-4-fluor-
ophenoxyacetate(CAS name), dichloro-8-quinolinecarboxylic acid,
trichloro-2-pyridinyloxyacetic acid, glyphosate,
glufosinate-ammonium, derivatives of phenoxyacetic acid,
phenoxypropionic acid, phenoxybutyric acid,
4-amino-3,5,6-trichloro-picolinic acid, phenoxyethyl sulphuric
acid, halogeneated benzoic acid, halogenated acetic acid,
halogenated propionic acid, phenylurea, or bipyridylium, and
certain mineral salts of sodium chlorate, sodium or potassium
2,4-dichlorophenoxyacetate, sodium or potassium
4-chloro-2-methylphenoxyacetate, sodium or potassium
2,4,5-trichlorophenoxyacetate, sodium or potassium
2-(4-chloro-2-methylphenoxy)-propionate, sodium or potassium
2-(2,4-dichlorophenoxy)-propionate, sodium or potassium
4-(2,4-dichlorophenoxy)-butyrate, sodium or potassium
4-(4-chloro-2-methylphenoxy)-butyrate, sodium or potassium
4-(2,4,5-trichlorophenoxy)-butyrate, sodium or potassium
4-amino-3,5,6-trichloropicolinate, sodium
2-(2,4-dichlorophenoxy)-ethylsulfate, 2,3,6-trichlorobenzoic acid,
3,6-dichloro-2-methoxybenzoic acid, sodium chloracetate,
trichloracetic acid, sodium 2,2-dichloropropionate, sodium
2,2,3-trichloropropionate, N,N-dimethyl-N'-phenyl urea and its
trichloracetic salt, the trichloracetate of
N,N-dimethyl-N'-(4-chlorophenyl) urea, copper suphate, iron
sulphate, 1,1'-dimethyl-4,4'-bipyridylium dichloride,
1,1'-bis(3,5-dimethyl-4-morpholinyl)-carbonylmethyl-4,4'-bipyridylium
dichloride, 9,10-dihydro-8a, 10a-diazaphenanthrene dibromide,
3-amino-1,2,4-triazole, symmetrical triazines and the like.
[0043] Suitable insecticides include one or more of the following:
dimethyl acetylphosphoramidothioate; ethanimidamide,
N-{(6-chloro-3-pyridinyl)methyl}-N'-cyano-N-methyl-, (E)-(9Cl)(CA
Index name); hydrazinecarboxylic acid,
2-(4-methoxy{1,1'-biphenyl}-3-YL)-, 1-methylethyl ester (9Cl) (CA
Index Name); methyl{1,1'-biphenyl}-3-YL)methyl
3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxyla-
te, {1.alpha.,3.alpha.(Z)}-(.+-.)-; naphthyl-n-methylcarbamate;
pyrrole-3-carbonitrile,
4-bromo-2-(4-chlorophenyl)-1-(ethoxymethyl)-5-(trifluoromethyl);
chloro-alpha-(1-methylethyl)benzeneacetic acid,
cyano(3-phenoxyphenyl)methyl ester
amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-(1,R,S)-(trifluorometh-
yl)sulfinyl)-1H-pyrazole-3-carbonitrile; benzoic acid, 4-chloro-,
2-benzoyl-2-(1,1-dimethylethyl)hydrazide (9Cl) (CA Index Name);
pyrethrins;
deoxy-2,3,4-tri-o-methyl-alpha-L-mannopyranosyl)oxy)-13-{{5-(dimethylamin-
o)tetrahydro-??methyl-2H-pyran-2-YL}oxy}-9-ethyl-2,3,3A,5A,5B,6,9,10,11,12-
,13,14,16A,
16B-tetradecahydro-14-methyl-1H-as-indaceno{3,2-D}oxacyclododecin-7,15-di-
one,(cont'd qual; oxadiazin-4-imine,
3-(2-chloro-5-thiazolyl)methylytetrahydro-5-methyl-N-nitro-(9Cl)
and the like.
[0044] Suitable fungicides for use in the present invention include
tetrachloroisophthalonitrile;
ethoxy-3-(trichloromethyl)-1,2,4-thiadiazole;
dichlorophenyl)-4-propyl-1,3-dioxolan-2-YL)methyl)-1H-1,2,4-triazole;
carbamic acid,
2-1-(4-chlorophenyl)-1H-pyrazol-3-ylyoxyymethylyphenylymethoxy-methyl
ester (CAS name);
dimethyl((1,2-phenylene)bis(iminocarbonothioyl))bis(carbamate) and
the like.
[0045] Suitable plant growth regulators for use in the present
invention include
RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-YL)-
pentan-3-OL; cyclohexanecarboxylic acid,
4-(cyclopropylhydroxymethylene)-3,5-dioxo-,ethyl ester.
[0046] Other examples of biologically active ingredients which may
be employed in preparing the granular compositions of this
invention include (z)-11-tetradecenyl acetate;
1,2-benzisothiazolin-3-on; 1,2-Dibromoethane;
1,3-dichloro-5,5-dimethylhydantoine;
1,3-dichloro-5-ethyl-5-methylhydantoine;
1-bromo-3-chloro-5,5-dimethylhydantoine; 1-Chloro-2,3-epoxyethane;
1-methylcyclopropene;1-naftylacetamide; 1-naftylacetic acid;
2-(thiocyanomethylthio)benzothiazole; 2,2
dibromo-3-nitrilopropionamide; 2,2'-Bipyridyl;
2,2-dithiobisbenzamide; 2,4,5-T, 2,4-D, 2,4-DB;
2,4-Dichloroanisole; 2,4-Dichlorobenzoic acid; 2,4-Dichlorophenol;
2,6-Dichlorophenol; 2-Aminopyridine;
2-bromo-2-nitro-1,3-propanediol; 2-bromo-4-hydroxyacetofenon;
2-phenylfenol; 2-methyl-4-isothiazolin-3-on; 2-methylthio-4-tert.
butylamino-cyclopropylamino-s-triazine; 3-indolylacetic acid;
4,4'-Bipyridyl; 4,6-Dichloro-2-methylphenoxyacetic acid;
4,6-Dichloro-o-cresol; 4,6-Dichloro-o-tolyloxyacetic acid;
4-chloro-2-benzylfenol; 4-chloro-3-methyl-sodiumfenolate;
4-Chloro-m-cresol; 4-Chloro-o-cresol;
5-chloro-2-methyl-4-isothiazolin-3-on;
5-oxo-3,4-dichloro-1,2-dithiol; 6-Chloro-2-methylphenoxyacetic
acid; 6-Chloro-o-tolyloxyacetic acid; 6-Chloro-p-cresol;
abamectine; Acephate; acetamiprid; aclonifen; Alachlor; Aldicarb;
Aldrin; alkylarylpolyglycolether;
alkyldimethylbenzylammoniumchloride;
alkyldimethylethylbenzylammoniumchloride;
alkyltrimethylammoniumchloride; alpha-Cypermethrin;
alpha-Cypermethrin; aluminium-phosphide; aluminiumsulfate; Ametryn;
amfotensides; Amidate; amidosulfuron; Aminocarb; Amitraz; Amitrole;
ammoniumbichromate; ammoniumbifluoride; ancymidol; Anilazine;
arsenepentoxide; Asulam; Atrazine; auxin; azaconazole;
azadirachtine-a; azamethifos; Azinphos-methyl; azocyclotin;
azoxystrobin; bariummetaborate; amber acid dialdehyde; beauveria
bassiana; benazolin-ethyl; Bendiocarb; Benfluralin; Benfuracarb;
Benomyl; Bensulfuron-methyl; Bensultap; Bentazone;
benthiavalicarb-isopropyl; Benzoylprop-ethyl; benzyladenine;
benzylbenzoate; beta-Cyfluthrin; BHTO; bifenazate; Bifenox;
bifenthrin; Binapacryl; Bioallethrin; Bis(ethylenediamine) copper;
Bitertanol; bitumen; borate; Borax; boric acid; boscalid;
Brodifacoum; Bromacil; Bromadiolone; Bromocresol green; Bromophenol
blue; Bromophos; Bromothymol blue; Bromoxynil; bromuconazole;
bromo-chloro-5,5-dimethylhydantoine mixtures; bromofenoxim;
bromonitrostyrene; bromopropylate; buminafos; bupirimate;
buprofezin; Butachlor; butocarboxim; butoxycarboxim; Butylate;
Butylmagnesium chloride; calciumcyanide; calciumhypochlorite;
Captan; carbaryl; carbeetamide; Carbendazim; carbendosulf;
Carbetamide; Carbofuran; Carbon disulphide; Carbosulfan; carboxin;
carfentrazone-ethyl; Cartap; Cetylpyridinium bromide;
Chinomethionat; chlofentezin; Chloramben; Chlordimeform;
chlordioxide; chlorfacinon; chlorfenoxyacetic acid;
Chlorfenvinphos; Chloridazon; Chlormequat; Chlorobenzilate;
chlorobromuron; chlorodecone; Chloropropylate; Chlorothalonil;
chlorotoluron; Chloroxuron; Chlorphoxim; Chlorpropham;
Chlorpyrifos; Chlorsulfuron; Chlorthal; cinidon-ethyl;
cis-dichloropropene; clodinafop-propargyl; Clofentezine; clomazone;
clopyralid; codlemon; Congo red; coniothyrium minitans; Copper;
Copper ethylenediamine sulphate; copper(i)oxide;
copper(ii)carbonatehydroxide; copper(ii)oxide; copperhydroxide;
coppemaftenate; copperoxychinolate; copperoxychloride;
copperresinate; coppersilicofluoride; coppersulfate;
copperthiocyanate; Coumatetralyl; Cyanazine; hydrocyanic acid;
cyazofamid; Cycloate; Cycloxydim; cyfenothrin; Cyfluthrin;
Cyhexatin; Cymoxanil; Cypermethrin; Cyproconazole; cyprodinil;
cyromazin; Dalapon; d-allethrin; daminozide; dazomet; DDT;
Deltamethrin; d-empenthrin; Deschlorophosphamidon; desmedifam;
Desmetryn; d-fenothrin; dialkyldimethylammoniumchloride; Diazinon;
Diazomethane; Dicamba; Dichlobenil; dichlofenthion; Dichlofluanid;
dichloran; Dichlorodifluoromethane; dichloropropene; Dichlorprop;
Dichlorvos; Diclofop; Dicofol; didecyldimethylammoniumchloride;
Dieldrin; dienochlor; diethofencarb; diethyl-m-toluamide;
difenacum; difenoconazole; difethialon; Diflubenzuron;
Diflufenican; Dimedone derivative; Dimercury dicyanide;
dimethenamide; Dimethoate; Dimethomorph; Dimethyl sulphate;
disodium octaborate; disodiumcyanodithioimidocarbonate; dinoseb;
Dinoterb; Dioxane; Diquat; Diquat dibromide; Disulfoton; Dithianon;
dithiocarbamate; Dithizone; diuron; d-karvon; dnoc;
dodecyldihydroxyethylbenzylammoniumchloride; dodemorf; Dodine;
d-tetramethrin; d-trans-Allethrin; Dustability; Edifenphos;
Endosulfan; Endrin; enilconazol; Epichlorhydrin; Epoxiconazole;
EPTC; Erichrome; Esfenvalerate; Ethephon; Ethiofencarb; Ethion;
Ethirimol; Ethofumesate; ethoprofos; ethyl
3-(n-n-butyl-n-acetyl)aminopropion; ethyleneoxide; Ethylenediamine
tetraacetic acid; Etofenprox; etridiazole; etrimfos; ETU;
famoxadone; fenamidone; fenamifos; fenarimol; Fenbutatin oxide;
fenchlorazole-ethyl; fenhexamide; Fenitrothion; fenmedifam;
Fenobucarb; Fenoprop; fenothrin; fenoxaprop-p-ethyl; fenoxycarb;
fenpiclonil; fenpropathrin; fenpropidin; Fenpropimorph;
Fensulfothion; Fenthion; Fentin; Fentin acetate; Fentin hydroxide;
Fenvalerate; ferri phosphate; Ferroin sulphate; ferrosulfate;
Fipronil; flocoumafen; florasulam; Fluazifop-butyl;
Fluazifop-P-butyl; fluazinam; flucycloxuron; fludioxonil;
flufenacet; Fluometuron; fluorglycofen-ethyl; fluoxastrobin;
flurenol; fluroxypyr; Flusilazole; flutolanil; Folpet; fonofos;
foramsulfuron; Formaldehyde; Formothion; fosalon;
fosetyl-aluminium; fosfamidon; fosmet; fosthiazate; foxim;
fuberidazole; furalaxyl; furathiocarb; gibbereline; gibberella;
Glufosinate; glufosinate-ammonium; glutaraldehyde;
glycolbromoacetate; glyphosate-trimesium; Glyphosate; guazatine;
haloxyfop-ethoxyethyl; haloxyfop-p-methyl; heptenofos; Hexadecanoic
acid; Hexazinone; hexythiazox; fenoxacrim; hydramethylnon; Hydrogen
sulphide; Hydroxylammonium chloride; hymexazole; Icaridin;
Imazalil; imazamethabenz-methyl; Imidacloprid; indoxacarb;
iodosulfuron-methyl-sodium; ioxynil; iprodion; isofenphos;
isoproturon; isoxaflutole; iodofore; kasugamycine; kresoxim-methyl;
lambda-Cyhalothrin; lenacil; lindane; linuron; magnesiumphosphide;
malathion; maleine hydrazide; mancozeb; maneb; MCPA; m-Cresol;
mecoprop; mecoprop-p; mepanipyrim; mesotrione; metalaxyl;
metalaxyl-m; metaldehyde; metamitron; metam-sodium; metarhizium
anisopliae, metazachlor; methabenzthiazuron; methamidophos;
methidathion; methiocarb; methomyl; methoprene; methoxyfenozide;
methylbromide; methylenebisthiocyanate; methylnaftylaceetamide;
methylnaftylacetic acid; metiram; metobromuron; metolachlor;
metoxuron; metribuzin; metsulfuron-methyl; mevinphos; milbemectin;
molinate; monobromoacetic acid; monocarbamide-dihydrogensulfate;
monolinuron; monuron; myclobutanil;
N-(2-ethylhexyl)-8,9,10-tribornene-2,3-dicarboxamide;
n,n-diallyldichloroaceetamide; sodium bichromate; sodium bisulfite;
sodium bromide; sodium chlorite; sodium dichloroisocyanurate;
sodium fluoracetate; sodium hydroxide; sodium hypochlorite; sodium
octaborate; sodium perborate; sodium-p-toluenesulfonchloramide;
nicosulfuron; nitrothal-isopropyl;
n-octylbicycloheptenedicarboximide; nonylfenol ethoxylate;
nuarimol; O,O-Dimethyl methylphosphoroamidothioate; O,O-Dimethyl
phosphoroamidothioate; O,O-Dimethyl
S-methylcarbamoylmethylphosphorodithioate; O,S-Dimethyl
methylphosphoroamidothioate;
O,S-Dimethyl-4-nitrophenylphosphorothioate; o-Cresol; octanoic
acid; octylfenoxypolyethoxyethanol; octylisothiazolin-3-on;
omethoate; oxadixyl; oxamyl; oxy-demeton-methyl; paclobutrazol;
paecilomyces fumosoroseus; paraformaldehyde; paraquat;
paraquat-dichloride; parathion (ethyl); parathion-methyl;
p-chloro-m-cresol; p-Cresol; penconazole; pencycuron;
pendimethalin; permethrin; phenoxyalkanoic herbicides;
p-hydroxyphenylsalicylamide; picloram; picoxystrobin;
piperonylbutoxide; pirimicarb; pirimiphos-ethyl; pirimiphos-methyl;
poly[oxyethylene(dimethyliminio)ethylene; polybutenen; Potassium
bichromate; Potassium bifluoride; Potassium hydroxide;
Potassium-n-methyldithiocarbamate; prochloraz; procymidon; profam;
prohexadione-calcium; prometryn; propachlor;
propamocarb-hydrochloride; propaquizafop; propetamphos; propham;
propiconazole; propoxur; propyzamide; prosulfocarb;
prothioconazole; pymetrozine; pyraclostrobin; pyrazophos;
pyrethrinen; pyridaben; pyridate; pyrifenox; pyrimethanil;
pyriproxyfen; quinmerac; quinoclamin; quinoxyfen; quizalofop-ethyl;
quizalofop-p-ethyl; rape seed oil; rimsulfuron; salicylic acid;
sethoxydim; simazine; s-methoprene; s-metolachlor; spinosad;
spirodiclofen; spiromesifen; streptomyces griseoviridis;
streptomycine-sulfate; sulcofuron; sulcotrione; sulfotep; Sulphur;
tebuconazole; tebufenpyrad; teflubenzuron; tefluthrin; temephos;
tepraloxydim; terbufos; terbuthylazine; terbutryn;
tetra-acetylethylenediamine; tetrachlorvinfos; tetradifon;
tetramethrin; thiabendazol; thiacloprid; thiamethoxam;
thifensulfuron; Thiobencarb; thiocyclam hydrogeneoxalate;
thiodicarb; thiofanate-methyl; thiometon; thiram; thiuram
disulphide; tolclofos-methyl; tolylfluanid; transfluthrin;
triadimefon; triadimenol; tri-allate; triazamate; triazophos;
tributyltinacrylatecopolymer; tributyltinfluoride;
tributyltinphosphate; tributyltinmethacrylate; tributyltinoxide;
trichlorfon; trichlorisocyanuric acid; trichoderma harzianum rifai
t-22; triclopyr; tridemorf; triphenyltinfluoride; trifloxystrobin;
triflumizol; triflumuron; trifluralin; triflusulfuron-methyl;
triforine; trinexapac-ethyl; urea herbicides; validamycine;
vamidothion; verticillium dahliae kleb.; verticillium lecanii;
saturated fatty acids; vinclozolin; warfarin; hydrogenperoxide;
Silverthiosulfate; zineb; zincborate; zincnaftenate; zincoxalate;
zincoxide; zincpyrithione; zincsilicofluoride; ziram;
.gamma.-Chlorophosphamidon and the like.
[0047] To ensure that the granular agrochemical composition
releases essentially all of its active ingredient (ie, greater than
90% and, preferably, greater than 99%), the core material should
release slower than the active ingredient. Otherwise, residues of
active ingredient would remain in the controlled release system
after complete release of the core material.
[0048] In a preferred embodiment of the present invention, the
granular core material employed for preparing the compositions is
at least partially water soluble and may comprise any of a variety
of well known, standard NPK or other such fertilizer granules such
as those described in European Community Regulation (EC) No.
2003/2003. Alternatively, the core material may be a water-soluble
salt or other such material, e.g. sodium-salts or
calcium-salts.
[0049] Also, other non-ionic materials may be suitable for use in
forming the core of the present compositions, particularly, those
which can provide osmotic pressure when dissolved. Examples, of
such materials are sugar and urea granules.
[0050] Typically, the materials for use in forming the core for the
compositions of this invention should have a solubility of about 2
to about 800 g/l, preferably, about 120-450 g/l. Also, the core
material should be shaped as a granule having a diameter of about
0.35 to about 6 mm, preferably, about 0.72-4 mm for better
distribution of the product.
[0051] Preferably, the wax material to be employed for use in
preparing the first coating layer should have a melting point
between about 50.degree. C. and the degradation temperature of the
active ingredient or core material, preferably above about
80.degree. C. The wax can be hydrophobic or hydrophillic.
[0052] Exemplary of suitable waxes for use herein are higher
alkenes; stearamides; polyolefines such as polyethylene, oxidized
polyethylenes, polypropylene, polyisobutylene, styrene-based
polymers; (block) copolymers of polyolefines; polyesters; (block)
copolymers of polyesters; polyethers, e.g. poly(ethylene oxide),
poly(propylene oxide); (block) copolymers of polyethers; vinyl
resins such as poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl
chloride), poly(vinylidene chloride), poly(vinyl pyrrolidone),
poly(vinyl acetal), poly(vinyl methylacetamide); acrylic polymers;
cellulose derivatives, e.g. celluloseacetate; polyamides;
polyamines; polyimides; polycarbonates; polysulfones; polysulfides;
polysaccharides. Also blends of these waxes can be used.
[0053] In a further preferred embodiment of this invention the
biologically active ingredient or plant protection product for
incorporation in the wax to form the first coating layer should be
selected from the group consisting of insecticides, herbicides,
fertilizers, growth regulators, pheromones, biostimulants,
acaricides, miticides, nematocides, fungicides and mixtures thereof
and the like.
[0054] The controlled release systems of this invention enable
economical application of a total amount of active ingredient
necessary for season long control without increased risk of
leaching, phytotoxicity for crops and is safe for users. The active
ingredient is applied without the use of a solvent. Thus,
low-solubility active ingredients can be used. Significantly, the
system is efficient. At most, only very limited amounts, preferably
less than about 10% by weight and, most preferably, less than about
1% by weight, of the active ingredient should be left inside the
system.
[0055] In order to achieve the high efficiency of release
characteristics of the compositions of the present invention, it is
preferred to adjust the water-solubility of the core material to
correspond to the water-solubility of the active ingredient. When
the core material-solubility is too high compared to the active
ingredient-solubility, all of the core-material may be released
before the release of all the active ingredient. This results in
residue of active ingredient in the granules which is not desirable
from an environmental and commercial point of view. If the
solubility of the core material is too low compared to the
solubility of the active ingredient, too much of the core material
may be left in the composition after the release of the active.
This results in an inefficient use of the core material.
[0056] The solubility of the active ingredient and core material
may be influenced by additives, such as ionic or non-ionic
surfactants, water-soluble polymers or complexing agents. Not all
active ingredients demonstrate good water-solubility. Increasing
the solubility of an active ingredient, for example, by using a
non-ionic surfactant for the active ingredient application renders
the actives more soluble and may make the compositions of this
invention more widely applicable. Not only the solubility of the
core material but, also, the dissolving rate of the core material
versus the active ingredient should be considered in formulating
the compositions of this invention. Typically, the ratio of core
material to active ingredient should be about 1000 to about 0.1
and, preferably, about 200-10. After the release period, less than
about 10%, preferably, less than 1% of the initial amount of active
ingredient should be present inside the controlled release system.
To achieve the desired release longevity of the compositions of
this invention, the coating thickness employed should be matched
with the solubility of the core material and the active
ingredient.
[0057] Furthermore, it should be noted that the longevity of
release of the active ingredients of the present compositions can
be modified by varying the amount of polymeric coating employed.
Alternatively, the water-permeability of the polymer coating can be
changed. The polymer coating layer can be formed from any
(semi-)water-permeable polymeric material, including copolymers,
known in the art such as known thermosetting resins, thermoplastic
resins and other polymeric materials or latex polymers and mixtures
thereof. The polymer coating enables slow release of the active
ingredient over a period of about 6 to about 104 weeks, preferably,
about 3-6 months.
[0058] Exemplary of suitable polymers for use in the present
invention are such thermoplastic coating materials as vinyl resins
such as poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl
chloride), poly(vinylidene chloride), poly(vinyl pyrrolidone),
poly(vinyl acetal), poly(vinyl methylacetamide); polyolefines such
as polyethylene, polypropylene, polyisobutylene; styrene-based
polymers; acrylic polymers; polyesters such as poly(alkylene
terephthalate), poly(caprolactone); poly(oxy alkylene)s, such as
poly(ethylene oxide), poly(propylene oxide); cellulose derivatives,
such as celluloseacetate; polyamides; polyamines; polycarbonates;
polyimides; polysulfones; polysulfides; polysaccharides and the
like.
[0059] Suitable thermosetting polymeric coating materials for use
herein include polyesters such as alkyds or modified alkyds; epoxy
resins; urethane resins; and aminoplastics.
[0060] In a most preferred embodiment of this invention, the
polymeric composition for use in forming the second coating layer
comprises a dicyclopentadiene ("DCPD") polymeric product
(containing either linseed oil or an alkyd resin based on a soybean
oil) such the polymer coatings employed to produce such fertilizers
as those sold by the Scotts Company under the trademark
Osmocote.RTM. as disclosed in U.S. Pat. No. 3,223,518 and U.S. Pat.
No. 4,657,576.
[0061] In preparing the present compositions, the active ingredient
is applied onto the granular core material with a wax. Preferably
the active ingredient/wax combination is a solid at room
temperature and it is applied onto the granular core material as a
liquid. The active ingredient can be mixed with a (molten) wax and
applied drop wise or sprayed onto the granular material. The active
ingredient does not need to dissolve. The mixture of active
ingredient and wax can be applied as a dispersion. In addition,
functional additives such as surfactants, which are used to modify
the water solubility, can be applied with the active ingredients.
The use of ionic or non-ionic surfactants enables use of active
ingredients in the present compositions that have a low solubility
in water, thus, broadening their applicability. Also, waxes that
are non-ionic surfactants can be used herein.
[0062] The present invention encompasses both granular controlled
release agrochemical compositions and processes for the preparation
thereof and addresses the problems encountered with regard to
functionality of prior compositions in terms of active ingredient
release over an extended period of time.
[0063] The compositions and processes of the present invention are
further illustrated by the examples below. The examples serve only
to illustrate the invention and should not be interpreted as
limiting since further modifications of the disclosed invention
will be apparent to those skilled in the art. All such
modifications are deemed to be within the scope of the invention as
defined in the claims.
EXAMPLE 1
[0064] A sample of the granular agrochemical compositions of the
present invention was prepared employing an 0-2-40 fertilizer
granule obtained from The Scotts Company (Howden, UK) as the
granular core material. This granular core was predominantly
composed of potassium sulfate. The sample composition was prepared
by initially heating 50 g of the 0-2-40 fertilizer granules
(1.7-2.0 mm) in a rotating drum to 110.degree. C. Then, 0.75 g of a
non-ionic surfactant wax (a polyethyleneglycol-block-polyethylene,
cas nr.: [251553-55-6], hydroxyl number 52.00 mg KOH/g, containing
20% (by weight) polyethylene glycol, obtained from Sigma-Aldrich),
was melted and 0.25 g of a biologically active ingredient
(imidacloprid, obtained from Sigma-Aldrich) was mixed into in the
molten wax.
[0065] Then, the resulting mixture of imidacloprid and wax was
added to the warm fertilizer (potassium sulfate) granules to form a
coating layer on the granular core. The granules with the
imidacloprid and wax coating thereon were allowed to cool to room
temperature. Subsequently, a second coating layer was applied over
the imidacloprid and wax coating layer according to the following
procedure. The active-impregnated granules were heated 15 minutes
in a rotating flask in an oil-bath at 95.degree. C. A modified
unsaturated oil copolymer based alkyd resin sold under the trade
name Necolin S9363 by Ashland-Sudchemie-Kemfest GmbH, Germany, was
added to the warm granules over a 40 minute period. The solid
content of the added resin was 40%. White spirit was used as a
solvent and a drier was used to enhance the curing. During the
process of applying the second polymer coating layer, air was
purged through the system to evaporate the solvent from the resin.
After coating 5.5 pph (parts per hundred by weight) on the granular
composition having the first coating layer thereon, the resulting
composition was cooled to room temperature and was ready for
testing. The imidacloprid concentration in this composition was
0.30% by weight as determined by standard High Performance Liquid
Chromatography chemical analytical analysis techniques.
[0066] The test sample of this Example 1 was subjected to release
testing wherein the release of the active ingredient from the
coated granular composition was evaluated in water in a so-called
waterleach test. For this waterleach test, 200 ml of water was
added to 10 g of the coated granular composition. Then the sample
was stored at 21.degree. C. and the water was replaced completely
with fresh water after 1 day and at weekly intervals thereafter.
The removed water was analyzed on active ingredient content with
standard analytical methods. For example, the imidacloprid active
ingredient release from the test samples of Example 1 was analyzed
with HPLC, column: inertsil ODS-2 150.times.4.6 mm, eluens
acetonitrile/water (pH=3 with phosphoric acid).
[0067] The release profile was calculated from the initial active
ingredient concentration in the granule. The core dissolution was
calculated from the measured conductivity. The measured
conductivity can be translated into a total amount of nutrients
released using the appropriate calibration constants. These
calibration constants are specific for a particular type of
fertilizer and are determined experimentally.
[0068] The result of this analytical evaluation was graphed on the
basis of percentage release of active ingredient versus percentage
release of water soluble core material over a time period up to 287
days as illustrated in FIG. 1. As can be seen from the graphic
display in FIG. 1, the granular composition having the biologically
active imidacloprid ingredient incorporated into the non-ionic
surfactant wax provided an effective and efficient system for
release of the active ingredient over a period of greater than 30
days. In fact, as demonstrated by the results shown in FIG. 1, the
compositions of this invention provided a release of about 95% (by
weight) of the active ingredient over a period of 287 days from the
date of initial exposure to moisture while about only about 50% (by
weight) of the core material was released over that same time
period so that about 50% (by weight) of the water soluble portion
of the granular core material remained within the granular
composition over the 287 day duration.
EXAMPLE 2
[0069] The composition produced in accordance with this Example 2
is distinguishable from the compositions produced in accordance
with Example 1 in regard to the wax material employed in forming
the first coating layer of test sample of the granular agrochemical
composition of the present invention. The procedure used to produce
the test sample of this Example 2 was in accordance with the
process of Example 1.
[0070] Specifically, an 0-2-40 fertilizer granule obtained from The
Scotts Company which was predominantly composed of potassium
sulfate was employed as the granular core material for the sample
composition which was prepared by initially heating 50 g of the
0-2-40 fertilizer granules (1.7-2.0 mm) in a rotating drum to
110.degree. C. Then, 0.75 g of a
polyethyleneglycol-block-polyethylene, cas nr.: [97953-22-5],
hydroxyl number 55.00 mg KOH/g, containing 50% (by weight)
polyethylene glycol, obtained from Sigma-Aldrich) was melted and
0.25 g of a biologically active ingredient (imidacloprid, obtained
from Sigma-Aldrich) was mixed into the molten wax. This wax
differed from the wax employed in Example 1 but possessed similarly
suitable surfactant characteristics for the imidacloprid
biologically active ingredient which was incorporated by mixing
into in the molten wax as described in Example 1.
[0071] Then, the resulting mixture of imidacloprid and wax was
added to the warm fertilizer (potassium sulfate) granules to form a
coating layer on the granular core. The granules with the
imidacloprid and wax coating thereon were allowed to cool to room
temperature. Subsequently, the same polymeric second coating layer
as described in Example 1 was applied over the imidacloprid and wax
coating layer employing the same procedure as in Example 1 to
produce the granular composition for testing. The imidacloprid
concentration in the composition of this Example 2 was 0.22% (by
weight) as determined by standard High Performance Liquid
Chromatography chemical analytical analysis techniques.
[0072] The composition of this Example 2 was subjected to the
release testing procedure as described in Example 1 and the results
of this testing is illustrated in FIG. 2. As can be seen from the
graphic display in FIG. 2, this granular composition having the
biologically active imidacloprid ingredient incorporated into the
wax provided an effective and efficient system for release of the
active ingredient over a period of greater than 30 days. In fact,
as demonstrated by the results shown in FIG. 2, the composition of
this invention provided a release of about 96% (by weight) of the
active ingredient over a period of 287 days from the date of
initial exposure to moisture while only about 65% (by weight) of
the core material was released over that same time period so that
about 35% (by weight) of the water soluble portion of the granular
core material remained within the granular composition over the 287
day duration.
EXAMPLE 3
[0073] The composition produced in accordance with this Example 3
is distinguishable from the compositions produced in accordance
with Example 2 in regard to the amount of the active ingredient
which was incorporated into the wax material in forming the first
coating layer of test sample of the granular agrochemical
composition of the present invention.
[0074] The procedure used to produce the test sample of this
Example 3 was in accordance with the process of Example 1.
Specifically, an 0-2-40 fertilizer granule obtained from The Scotts
Company which was predominantly composed of potassium sulfate was
employed as the granular core material for the sample composition
which was prepared by initially heating 50 g of the 0-2-40
fertilizer granules (1.7-2.0 mm) in a rotating drum to 110.degree.
C. Then, 0.75 g of a polyethyleneglycol-block-polyethylene, cas
nr.: [97953-22-5], hydroxyl number 55.00 mg KOH/g, containing 50%
polyethyleneglycol, obtained from Sigma-Aldrich) was melted and
0.75 g of a biologically active ingredient (imidacloprid, obtained
from Sigma-Aldrich) was mixed into the molten wax. This amount of
biologically active ingredient is higher than the amount used in
Example 2.
[0075] Then, the resulting mixture of imidacloprid and wax was
added to the warm fertilizer (potassium sulfate) granules to form a
coating layer on the granular core. The granules with the
imidacloprid and wax coating thereon were allowed to cool to room
temperature. Subsequently, the same polymeric second coating layer
as described in Example 1 was applied over the imidacloprid and wax
coating layer employing the same procedure as in Example 1 to
produce the granular composition for testing. The imidacloprid
concentration in the composition of this Example 3 was 0.95% by
weight as determined by standard High Performance Liquid
Chromatography chemical analytical analysis techniques.
[0076] The composition of this Example 3 was subjected to the
release testing procedure as described in Example 1 and the results
of this testing is illustrated in FIG. 3. As can be seen from the
graphic display in FIG. 3, this granular composition having the
biologically active imidacloprid ingredient incorporated into the
wax provided an effective and efficient system for release of the
active ingredient over a period of greater than 30 days. In fact,
as demonstrated by the results shown in FIG. 3, the composition of
this invention provided a release of about 86% (by weight) of the
active ingredient over a period of 175 days from the date of
initial exposure to moisture while only about 67% (by weight) of
the core material was released over that same time period so that
about 33% (by weight) of the water soluble portion of the granular
core material remained within the granular composition over the 175
day duration.
EXAMPLE 4
[0077] The composition produced in accordance with this Example 4
is distinguishable from the compositions produced in accordance
with Example 1 in regard to the active ingredient which was
incorporated into the wax material in forming the first coating
layer of test sample of the granular agrochemical composition of
the present invention and in regard to polymer composition which
was employed in forming the second coating layer on the
compositions. The procedure used to produce the test sample of this
Example 4 was in accordance with the process of Example 1.
[0078] Specifically, an 0-2-40 fertilizer granule obtained from The
Scotts Company which was predominantly composed of potassium
sulfate was employed as the granular core material for the sample
composition which was prepared by initially heating 50 g of the
0-2-40 fertilizer granules (1.7-2.0 mm) in a rotating drum to
110.degree. C. Then, 3.5 g of the non-ionic surfactant wax of
Example 1 (a polyethyleneglycol-block-polyethylene, cas nr.:
[251553-55-6], hydroxyl number 52.00 mg KOH/g, containing 20% by
weight polyethyleneglycol, obtained from Sigma-Aldrich), was melted
and 3.5 g of a Fosetyl-Aluminum biologically active ingredient
obtained from Bayer CropSciences was incorporated by mixing into
the molten wax by the same procedure described in Example 1.
[0079] Then, the resulting mixture of Fosetyl-Aluminum and wax was
added to the warm fertilizer (potassium sulfate) granules to form a
coating layer on the granular core. The granules with the
Fosetyl-Aluminum and wax coating thereon were allowed to cool to
room temperature. Subsequently, a polymeric second coating layer
was applied over the Fosetyl-Aluminum and wax by the process
described in Example 1 to produce the granular composition for
testing. The polymer employed as the second coating layer was a
modified unsaturated oil copolymer based alkyd resin sold under the
trade name Necolin 4071 by Ashland-Sudchemie-Kernfest GmbH,
Germany. The Fosetyl-Aluminum concentration in the composition of
this Example 4 was 4.75% (by weight) as determined by standard High
Performance Liquid Chromatography chemical analytical analysis
techniques.
[0080] The composition of this Example 4 was subjected to the
release testing procedure as described in Example 1 except that the
Fosetyl-Aluminium release was analyzed with ion-chromatography
column: Phenomenex starion A300:1050.times.4.6 mm, eluens 5%
acetone in water, with 1 mM HNO3 and 3 mM NaNO.sub.3 and the
results of this testing is illustrated in FIG. 4. As can be seen
from the graphic display in FIG. 4, this granular composition
having the biologically active Fosetyl-Aluminum ingredient
incorporated into the wax provided an effective and efficient
system for release of the active ingredient over a period of
greater than 30 days. In fact, as demonstrated by the results shown
in FIG. 4, the composition of this invention provided release of
99% (by weight) of the active ingredient over a period of about 267
days from the date of initial exposure to moisture while only about
50% (by weight) of the core material was released over that same
time period.
EXAMPLE 5
[0081] Another granular test sample compositions in accordance with
this invention was produced utilizing a hydrophobic wax material in
forming the first coating layer. The procedure used to produce the
test sample of this Example 5 was in accordance with the process of
Example 1.
[0082] Specifically, an 0-2-40 fertilizer granule obtained from The
Scotts Company which was predominantly composed of potassium
sulfate was employed as the granular core material for the sample
composition which was prepared by initially heating 50 g of the
0-2-40 fertilizer granules (1.7-2.0 mm) in a rotating drum to
110.degree. C. Then, 2.5 g of a hydrophobic wax (Novoflow 02102
obtained from Holland Novochem BV, Nieuwegein, the
Netherlands)--was melted and 2.5 g of a Fosetyl-Aluminum
biologically active ingredient obtained from Bayer CropSciences was
incorporated by mixing into the molten wax by the same procedure
described in Example 1.
[0083] Then, the resulting mixture of Fosetyl-Aluminum and wax was
added to the warm fertilizer (potassium sulfate) granules to form a
coating layer on the granular core. The granules with the
Fosetyl-Aluminum and wax coating thereon were allowed to cool to
room temperature. Subsequently, a polymeric second coating layer
was applied over the Fosetyl-Aluminum and wax by the process
described in Example 1 to produce the granular composition for
testing. The polymer employed as the second coating layer was a
modified unsaturated oil copolymer based alkyd resin sold under the
trade name Necolin 4071 by Ashland-Sudchemie-Kernfest GmbH,
Germany. The Fosetyl-Aluminum concentration in the composition of
this Example 5 was 3.5% by weight as determined by standard High
Performance Liquid Chromatography chemical analytical analysis
techniques.
[0084] The composition of this Example 5 was subjected to the
release testing procedure as described in Example 1 as modified in
Example 4 and the results of this testing is illustrated in FIG. 5.
As can be seen from the graphic display in FIG. 5, this granular
composition having the biologically active Fosetyl-Aluminum
ingredient incorporated into the hydrophobic wax provided an
effective and efficient system for release of the active ingredient
over a period of greater than 30 days. In fact, as demonstrated by
the results shown in FIG. 5, the composition of this invention
provided release of about 80% (by weight) of the active ingredient
over a period of about 266 days from the date of initial exposure
to moisture while only about 36% (by weight) of the core material
was released over that same time period so that about 64% (by
weight) of the water soluble portion of the granular core material
remained within the granular composition over the approximately 266
day duration. This result demonstrates the benefits derived from
employing a hydrophobic wax resulting in a slower releasing product
which is desirable when a highly soluble active ingredient is
incorporated therein.
[0085] Although the invention has been described in its preferred
forms with a certain degree of particularity, it is to be
understood that the present disclosure has been made by way of
example only. Those skilled in the art will recognize, or be able
to ascertain using no more than routine experimentation, many
equivalents to the specific embodiments of the invention described
herein. Such equivalents are intended to be encompassed within the
scope of the following claims.
[0086] All publications, patents and patent applications mentioned
in this specification are herein incorporated by reference into the
specification to the same extent as if each individual publication,
patent or patent application was specifically and individually
indicated to be incorporated herein by reference.
* * * * *