U.S. patent application number 11/920703 was filed with the patent office on 2008-08-14 for process for preparing ammonic glyphosate granules.
Invention is credited to Marco Bernardini, Francesca Borgo, Luigi Capuzzi, Edoardo Russo.
Application Number | 20080194409 11/920703 |
Document ID | / |
Family ID | 36997175 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080194409 |
Kind Code |
A1 |
Bernardini; Marco ; et
al. |
August 14, 2008 |
Process for Preparing Ammonic Glyphosate Granules
Abstract
A process for preparing water-soluble granules of amnionic
glyphosate comprising: a) addition of glyphosate acid to a
Broensted base which supplies ammonium ions in a molar ratio
base/acid comprised between 0.8 and 1.1; b) homogenization of the
mixture prepared in a); c) addition of one or more surfactants in
amounts in the range 5%-50% by weight based on the glyphosate acid;
d) mixing of the mass prepared in c) for a time lower than about 10
minutes until obtaining an extrudable mass; e) extrusion of the
mass obtained in d); f) drying until obtaining a granule having a
residual moisture lower than 1%.
Inventors: |
Bernardini; Marco; (Lodi,
IT) ; Borgo; Francesca; (Milano, IT) ;
Capuzzi; Luigi; (Novara, IT) ; Russo; Edoardo;
(Piacenza, IT) |
Correspondence
Address: |
ARENT FOX LLP
1050 CONNECTICUT AVENUE, N.W., SUITE 400
WASHINGTON
DC
20036
US
|
Family ID: |
36997175 |
Appl. No.: |
11/920703 |
Filed: |
May 23, 2006 |
PCT Filed: |
May 23, 2006 |
PCT NO: |
PCT/EP2006/004875 |
371 Date: |
November 19, 2007 |
Current U.S.
Class: |
504/206 |
Current CPC
Class: |
A01N 57/20 20130101;
A01N 25/12 20130101; A01N 57/20 20130101; A01N 2300/00
20130101 |
Class at
Publication: |
504/206 |
International
Class: |
A01N 25/12 20060101
A01N025/12; A01N 57/20 20060101 A01N057/20; A01P 13/00 20060101
A01P013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 17, 2005 |
IT |
MI2005A001138 |
Claims
1. A process for preparing water-soluble ammonic glyphosate
granules comprising: a) addition of glyphosate acid, under wet cake
form, to a solid Broensted base, which supplies ammonium ions, in
amounts equal to a molar ratio base/acid between 0.8 and 1.1,
preferably between 0.9 and 1.05, optionally in the presence of
coformulating agents such as inert, antifoam agents; b)
homogenization of the mixture prepared in a); c) addition of one or
more liquid surfactants, in amounts in the range 5%-50% by weight,
preferably 10%-40%, more preferably 12%-35% based on the glyphosate
acid; d) mixing of the mass prepared in c) for a time lower than
about 10 minutes, preferably lower than about 5 minutes, more
preferably comprised between about 30 seconds and 3 minutes, until
obtaining an extrudable mass; e) extrusion of the mass obtained in
d); f) drying until obtaining a granule having a residual moisture
lower than 116, preferably lower than 0.5%.
2. A process according to claim 1, wherein the Broensted base of
step a) is selected from ammonium carbonate, bicarbonate, carbamate
or mixtures thereof, optionally added of small amounts of
antipacking agents as, for example, magnesium carbonate.
3. A process according to claim 2, wherein the base is an equimolar
mixture of ammonium carbonate, bicarbonate, carbamate.
4. A process according to claims 1, wherein the inert agents of
step a) are selected from ammonium sulphate, potassium sulphate,
sodium sulphate, preferably ammonium sulphate.
5. A process according to claims 1, wherein the antifoam agent is a
silicone antifoam agent.
6. A process according to claims 1, wherein the step b) takes place
under mild stirring, preferably in a mixer working at a revolution
number between 20 and 40 rpm.
7. A process according to claims 1, wherein the surfactant addition
of step c) takes place under mild stirring, preferably in a mixer
working at a revolution number between 20 and 40 rpm.
8. A process according to claims 1, wherein the surfactant is
selected from solid or liquid surfactants at room temperature,
preferably from alkanol amide, betaine derivative,
ethoxylated-propoxylated block copolymer, glycerol ester, glycolic
ester, imidazoline and its derivatives, lanolin and lecithin
derivatives, tertiary and quaternary polyoxyalkylenalkyl amines,
polyoxyalkylen alkylether, polyoxyalkylen alkyl aryl ether,
polyoxyalkylen alkyl ester, alkoxylated and non alkoxylated
sorbitan ester, alkyl glycoside, alkyl polyglycoside, alkyl
sulphate, alkyl phosphate, sulphonated olefin, alkyl aryl
sulphonate, polyoxyalkylen alkyl ether sulphate, polyoxyalkylen
alkyl ether phosphate, sulphosuccinate derivative, taurate,
vegetable oil sulphonate of a fat acid, of an alcohol, of an
alcoholalkoxylate, of a fat acid ester, an aromatic derivative of a
fat acid ester or mixtures thereof, amine derivatives of vegetable
oils or of fat acids.
9. A process according to claims 1, wherein the surfactant is
ethoxylated tallow amine, having general formula
R--N(CH.sub.2CH.sub.2O)H.sub.m(CH.sub.2CH.sub.2O)H.sub.n with
R=saturated alkyl chain having 16-18 carbon atoms.
10. A process according to claims 1, wherein the step d) is carried
out under stirring with a higher intensity than that of step c),
preferably in a mixer, optionally equipped with chopper, working at
a rate between about 80 and 120 rpm.
11. A process according to claim 10, wherein the mixer choppers are
used.
12. A process according to claims 1, wherein the extrusion of step
e) is carried out by low pressure extruders, preferably basket
extruders.
13. A process according to claims 1, wherein the drying of step f)
is carried out in fluid bed dryers, preferably at temperatures in
the range 70.degree. C.-120.degree. C., more preferably 80.degree.
C.-100.degree. C.
14. A process according to claim 13, wherein the time used for
drying ranges from 10 to 15 minutes.
15. Granules of monoammonic glyphosate obtainable by the process of
claims 1.
16. Granules according to claim 15, wherein the content of
equivalent glyphosate acid is higher than or equal to 48% by
weight.
17. Granules according to claims 15, wherein the surfactant content
is between 5% and 25% by weight.
18. Granules according to claims 15, wherein the surfactant content
is between 10% and 20% by weight.
Description
[0001] The present invention relates to a process for preparing
water-soluble granules ammonic glyphosate-based to be used in the
agrochemical field.
[0002] The glyphosate (N-phosphonomethyl glycine) is well known in
the prior art as a compound having an herbicide activity effective
for the weed control. It is also known that the glyphosate, being
an organic acid not soluble in water, must be converted into its
salts to allow the use thereof. The most commonly used salts are
the isopropylamine salt, sodic salt and ammonic salt. The
isopropylamine salt is formulated and marketed under the form of
concentrated aqueous solution. However the need to save money in
the manufacturing, transportation and packing disposal costs has
recently brought to consider solid formulations, in particular
under the form of granules.
[0003] The sodic salt and the ammonic salt are particularly
suitable to water-soluble granules formulation, more particularly
the ammonic glyphosate as less hygroscopic and thus more resistant
in moist environment and besides more effective from the biological
point of view.
[0004] With the ammonic glyphosate term it is meant the glyphosate
monoammonic salt.
[0005] The water-soluble glyphosate granules can be prepared with
various processes.
[0006] For example, a known process comprises the salification step
of the glyphosate acid with a base, optional addition of other
coformulating agents as surfactants, inert agents, antifoam agents
and a subsequent granulation step by known techniques in the art as
extrusion, agglomeration, preferably extrusion (see for example
U.S. Pat. No. 5,633,397).
[0007] Another process comprises the mixing step of the glyphosate
acid, of the base, of the optional coformulating agents, and the
salification step in an extruder (see for example U.S. Pat. No.
5,070,197).
[0008] Another process describes the mixing under anhydrous
conditions of the glyphosate acid in powder form with a suitable
solid base, for example sodium acetate, with no salification
reaction; the latter taking place only when the granule is poured
into water before the use (see for example WO 92/12,637).
[0009] The salification of the glyphosate acid, when required, can
be carried out with various methods. In particular the ammonic
glyphosate can be prepared by using anhydrous or aqueous solution
ammonia, as salification base, by using processes comprising
mixing, reaction and extrusion in a single step (see for example
U.S. Pat. No. 5,070,197), or processes including separate steps
(see for example U.S. Pat. No. 5,633,397 and U.S. Pat. No.
6,734,142).
[0010] The processes using ammonia, show the advantage of being
carried out in a continuous way due to the high reaction rate
solid-gas and solid-liquid. However they suffer the following
drawbacks. The anhydrous ammonia is a toxic gas whose use in safety
conditions requires specific precautions not usually available in
agrodrug formulation plants. The ammonia in aqueous solution is
corrosive and also difficult to be safely handled. In both cases
the salification by using ammonia results to be strongly
exothermic. For these reasons expensive technical precautions in
the plant for the process management and for the operator safety
must be foreseen as, for example, temperature controls, cooling
circuits and safety systems.
[0011] A further drawback is noted in single step processes as the
equipments required for this kind of process are extruders normally
used in the plastic material extrusion, for example high pressure
screw extruders, wherein the temperature rises to levels so to make
particularly difficult the choice of coformulating agents, in
particular of the surfactant. Processes of this kind, requiring the
salification in the extruder, have never been described in low
pressure extruders usually utilized to produce water soluble or
dispersible granules in the agrochemical field. This is likely due
to the different configuration and different characteristics of a
low pressure extruders compared to high pressure extruders.
[0012] The above drawbacks can be overcome by using bases under the
solid form, for example ammonium bicarbonate, instead of the
ammonia (see for example U.S. Pat. No. 6,228,807). However these
processes show the drawback to require a particularly long
preparation step of the mass to be extruded: this step in fact
requires the complete salification of the glyphosate acid and this
takes place in a time of at least 20-30 minutes. Said
characteristic negatively affects the productivity of these
processes, a configuration of the salification zone in a continuous
way not being achievable. Besides, the salification step can
influence the consistence of the mass to be extruded and the
incorporation of the surfactant in the formulation.
[0013] As known, the surfactants have the purpose to favour, at the
time of the use, the glyphosate herbicide effectiveness by acting
on the permanence of the drop on leaves, on the adhesion of said
drops to the leaf surface and on the penetration of the active
principle through the cuticle.
[0014] It is desirable that in the final formulation the
surfactant, acting as an adjuvant, is present in amounts in the
range 5%-35% by weight with respect to the glyphosate, expressed in
equivalent acid. However an easy incorporation of high amounts of
surfactant only takes place when the formulations have a low
glyphosate content. On the other hand, in order to decreasing the
manufacturing, the granule transportation and the packing disposal
costs, solid products are required more concentrated in glyphosate,
making more difficult the incorporation of high amounts of
surfactant. As a matter of fact a high concentration of surfactant
is hardly adsorbed/absorbed by the mass containing glyphosate,
making the processing thereof difficult, especially in case of low
pressure extrusion.
[0015] Processes preparing ammonic glyphosate capable of containing
high surfactant amounts are known. However these processes use
anhydrous ammonia (see for example U.S. Pat. No. 5,633,397) or
ammonia in aqueous solution (see for example U.S. Pat. No.
6,605,568 and U.S. Pat. No. 5,716,903) and therefore with the above
technical drawbacks.
[0016] Processes for preparing granular compositions not requiring
the salification step are known. For example WO 92/12,637 requires
the mixing under anhydrous conditions of the glyphosate acid under
the powder form with a suitable solid base without any salification
reaction takes place which arises only when the granule is poured
in water before the use. This process, even though it does not
involve any salification step, shows however the drawback of being
carried out in a completely anhydrous environment, in case of the
soluble glyphosate salts, in order not to cause the salification
reaction before the use.
[0017] The need was felt to have available a process for preparing
ammonic glyphosate granules showing the following combination of
properties: [0018] no use of anhydrous ammonia or in aqueous
solution; [0019] having a preparation step of the extrudable mass
lower than 20 minutes, preferably lower than 10 minutes, and
therefore with a high productivity; [0020] carried out also in a
continuous way; [0021] allowing to obtain an extrudable mass in low
pressure extruders; [0022] capable of incorporating in the granule
formulation a high surfactant amount in combination with a high
glyphosate amount.
[0023] It has surprisingly and unexpectedly found that the
preparation of ammonic glyphosate granules with the process
described hereinafter allows to solve the above technical
problem.
[0024] It is therefore an object of the present invention a process
for preparing water-soluble ammonic glyphosate granules comprising:
[0025] a) addition of glyphosate acid, under the wet cake form, to
a solid Broensted base, which supplies ammonium ions, in amounts
equal to a molar ratio base/acid between 0.8 and 1.1, preferably
between 0.9 and 1.05, optionally in the presence of coformulating
agents such as inert, antifoam agents; [0026] b) homogenization of
the mixture prepared in a); [0027] c) addition of one or more
liquid surfactants, in amounts in the range 5%-50% by weight,
preferably 10%-40%, more preferably 12%-35% based on the glyphosate
acid; [0028] d) mixing of the mass prepared in c) for a time lower
than about 10 minutes, preferably lower than about 5 minutes, more
preferably comprised between about 30 seconds and 3 minutes, until
obtaining an extrudable mass; [0029] e) extrusion of the mass
obtained in d); [0030] f) drying until obtaining a granule having a
residual moisture lower than 1%, preferably lower than 0.5%.
[0031] In step a) wet cake means that the technical glyphosate acid
in powder contains water amounts between 5% and 20%, preferably
between 10% and 15%. In general the preferred water amount of the
wet cake is such to lead, depending on the used formulation, to an
extrudable mass having the consistence of a moist powder in a time
lower than 3 minutes when a Ploughshare type mixer, equipped with
"chopper" (additional low intensity and high shear strength mixing
devices) is used.
[0032] In step a) the solid Broensted base supplying ammonium ions
can be, for example, selected from ammonium carbonate, bicarbonate,
carbamate or mixtures thereof, optionally added of small amounts of
antipacking agents as, for example, magnesium carbonate. Preferably
the base in step a) is an equimolar mixture of ammonium carbonate,
bicarbonate, carbamate. In said solid base, if necessary, lumps, if
present, are reduced or removed before adding the other components.
Preferably the bicarbonate base is used in admixture with other
Broensted bases.
[0033] As inert agents to be added in step a), ammonium sulphate,
potassium sulphate, sodium sulphate, preferably ammonium sulphate,
can be mentioned. Preferably the inert agent is milled before being
added to the other components so as to have particle size lower
than 500 micron.
[0034] As antifoam agents, silicone antifoam agents can preferably
be mentioned. The antifoam agent can be added, alternatively, in
step c) together with the surfactant.
[0035] In step b) mild stirring is generally used, usually for a
time lower than one minute.
[0036] Homogenization is carried out, for example, in high stirring
intensity static mixers of the Ploughshare type, optionally
equipped with "choppers" or in continuous mixers having high shear
strength. Preferably in this step b) the choppers are not used.
Generally, in case of Ploughshare type mixers, mild stirring means
that the revolution number is generally between 20 and 40 rpm.
[0037] In step c) the surfactant addition is preferably carried out
under mild stirring. Stirring can be of the same type (intensity)
as that used in step b).
[0038] In step c) the surfactant is, for example, selected from
solid or liquid compounds at room temperature, for example alkanol
amide, betaine derivative, ethoxylated-propoxylated block
copolymer, glycerol ester, glycolic ester, imidazoline and its
derivatives, lanolin and lecithin derivatives, tertiary and
quaternary polyoxyalkylenalkyl amines, polyoxyalkylen alkylether,
polyoxyalkylen alkyl aryl ether, polyoxyalkylen alkyl ester,
alkoxylated and non alkoxylated sorbitan ester, alkyl glycoside,
alkyl polyglycoside, alkyl sulphate, alkyl phosphate, sulphonated
olefin, alkyl aryl sulphonate, polyoxyalkylen alkyl ether sulphate,
polyoxyalkylen alkyl ether phosphate, sulphosuccinate derivative,
taurate, vegetable oil sulphonate of a fat acid, of an alcohol, of
an alcoholalkoxylate, of a fat acid ester, an aromatic derivative
of a fat acid ester or mixtures thereof, amine derivatives of
vegetable oils or of fat acids.
[0039] Preferably said surfactant is added in a liquid form to the
mixture obtained in step b).
[0040] Preferably as surfactant ethoxylated tallow amine is used,
having general formula
R--N(CH.sub.2CH.sub.2O)H.sub.m(CH.sub.2CH.sub.2O)H.sub.n
(R=saturated alkyl chain having 16-18 carbon atoms).
[0041] Step d) is preferably carried out under stirring with higher
intensity than that of step c). In the above Ploughshare type
mixers, rates between about 80 and 120 rpm are generally used.
Preferably in this step choppers are used.
[0042] In step d) the mass mixing preferably takes place in the
same device wherein the previous step c) has been carried out but
increasing the shear rate so as to obtain an extrudable mass, that
is a mass having a consistence suitable to be extruded in the used
extruder.
[0043] The consistence suitability mainly depends on the technology
selected for the granulation: said consistence can range from a
moist powder consistence to a dough-like consistence; it is
preferable to have a consistence lower than the dough-like
consistence.
[0044] In the particular case of granulation by low pressure
extruders of the so called radial, basket or twin dome type, the
suitable consistence is that of a moist powder capable to be
plastically deformed when subjected to compression (for example in
the hand palm). A suitable extruder to carry out the process of the
invention is a low pressure extruder basket type.
[0045] Without to be bound to any theory, the Applicant keeps that
the optimal conditions to carry out step d) are: mass mixing for a
time sufficient to obtain an extrudable mass as defined above.
[0046] Generally, by using Ploughshare mixers at the above rates,
the extrudable mass can be obtained even with times lower than one
minute.
[0047] Preferably, during the time wherein step d) takes place, the
temperature remains substantially constant.
[0048] The mass obtained after the mixing d) is essentially formed
of unreacted glyphosate acid, ammonic glyphosate, Broensted base.
As a matter of fact the Applicant has unexpectedly and surprisingly
found that the completion of the salification reaction is not a
necessary condition for obtaining, before, an extrudable mass, and,
after, a good granule based on ammonic glyphosate.
[0049] The unreacted glyphosate acid is present in the mass
obtained in d) preferably in amounts ranging from a maximum of 70%
to a minimum of 10% with respect to the initial acid amount. It
follows that ammonic glyphosate in a minimum molar amount of 30%
and a maximum of 90% with respect to the starting glyphosate acid
and the corresponding amount of unreacted base will be present in
the extrudable mass.
[0050] The presence of unreacted glyphosate acid and thus of
unreacted Broensted base in the extrudable mixture is shown from
the carbon dioxide development (effervescence) when a portion of
the mixture obtained in the mixing step d) is put in water. As
said, during step d) the mass temperature substantially remains
unchanged.
[0051] In step e) the extrusion of the mass obtained in d) is
preferably carried out by low pressure extruders and produces
strings, which break by fall in coherent and moist granules to be
dried. Said granules, when put in water, show gas development.
[0052] In step f) drying is preferably carried out in fluid bed
dryers, generally at temperatures in the range 70.degree.
C.-120.degree. C., preferably 80.degree. C.-100.degree. C. The
drying temperature is however such as not to imply degradation or
loss of surfactant or of other formulation additives.
[0053] The dried granules obtained in step f), when put in water,
do not show any gas development but are completely water-soluble
without carbon dioxide development and without undissolved
sediments. This means that the salification is completed during
step f). The drying step generally lasts between 10 and 15 minutes
or at any rate for a time such as to obtain a granule having the
above characteristics when put in water, and a residual moisture
lower than 1%, preferably lower than 0.5%.
[0054] The Applicant has found that with the process of the present
invention it is possible to prepare water-soluble ammonic
glyphosate granules by a simple process, not requiring the use of
dangerous substances, not implying heat development, allowing the
incorporation in the formulation of high amounts of surfactant.
Furthermore the process of the present invention has realization
times much lower than those of known processes requiring the
salification step. It thus follows a higher productivity, the time
and the initial amount of components being equal, besides the
possibility to carry out the process of the present invention even
in a continuous way.
[0055] It has besides been found that with the process of the
present invention it is possible to remarkably increase the
surfactant content in the granule. As said above, this is a highly
desired characteristic for the glyphosate granules.
[0056] The granules obtainable with the process of the invention
have an equivalent glyphosate acid content higher than or equal to
48% by weight and a surfactant content in the range 5%-25% by
weight, preferably 10%-20% by weight.
[0057] Preferred compositions are the following (% by weight):
TABLE-US-00001 1. pure ammonic glyphosate 79.2 (equivalent acid 72)
surfactant 10 inert agents and impurities to 100 2. pure ammonic
glyphosate 79.2 (equivalent acid 72) surfactant 15 inert agents and
impurities to 100 3. pure ammonic glyphosate 74.8 (equivalent acid
68) surfactant 15 inert agents and impurities to 100 4. pure
ammonic glyphosate 66 (equivalent acid 60) surfactant 20 inert
agents and impurities to 100
[0058] The surfactant preferably used in these compositions is
tallow amine.
[0059] Some illustrative but not limitative Examples of the
pre-sent invention follow.
EXAMPLES
Characterization
Determination of the Glyphosate Acid Content in the Granule
[0060] It was determined by analytical method CIPAC 284/SG/M by
using the HPLC (High Performance Liquid Chromatography) technique
with ionic exchange column, wave length UV 195 nm and external
standard.
Determination of the pH of the Granule Dissolved in Water
[0061] It was determined by CIPAC 75 method by using a common
pHmeter.
Determination of the Granule Solubility
[0062] The glyphosate granule solubility was determined by the
following method.
[0063] A granular product amount having a known glyphosate acid
content is weighed so as to obtain 100 ml of a solution containing
glyphosate acid in concentration 5 times higher than the employment
dose (employment dose=14.4 g/l). The aqueous solution is prepared
by stirring for two minutes with a glass rod, the product is poured
in a 100 ml graduated conical cylinder ASTM D 96. The cylinder is
then capped and turned over 15 times in about 1/2 minute. Then the
solution is allowed to rest for 1 hour in a bath at a temperature
of 20.degree. C..+-.2. Then the presence of possible sediments is
visually controlled with a .+-.0.05 ml precision.
Determination of the Residual Moisture Content of the Granule
[0064] It was determined by the CIPAC MT 30.1 method.
Example 1
[0065] 2,348 grams of an equimolar mixture of ammonium carbonate,
bicarbonate and carbamate, commercially known as Hartshorn salt
(E503) having ammonia titre of 31%, were cleared removed from lumps
in a Loedige mixer (of the Ploughshare type) equipped with chopper;
8,297 grams of technical glyphosate having titre 96.9% with respect
to the dry product and moisture 10%, 776 grams of ammonium sulphate
previously milled by a rung mill were then added and mixed for one
minute. While maintaining the mixture under mild stirring,
corresponding to 20 rev/minute, 1,000 g of tallow amine
(surfactant) Emulson.RTM. AG/PE 3SS (corresponding to a content of
10% by weight based on the final composition and of 13% by weight
based on the acid) and 10 grams of antifoam agent Antifoam.RTM. SL
were added.
[0066] The obtained mass was then subjected to mixing at the
maximum intensity corresponding to 100 rev/minute, with the aid of
a chopper for 3 minutes until obtaining an extrudable mixture.
[0067] The mixture had the consistence of a moist powder,
deformable by compression in a hand.
[0068] The mass temperature during said step maintained itself
lower than 35.degree. C.
[0069] Said mixture was then sent to a low pressure basket extruder
having a diameter of 130 mm and a screen with 1 mm thickness and
holes, and extruded.
[0070] The extruded product was then dried in a fluid bed dryer for
15 minutes with hot air having an inlet temperature of 100.degree.
C.
[0071] The whole process was monitored by carrying out some
solubility test of the mass to be extruded, of the extruded granule
and of the dried granule, observing development of carbon dioxide
in case of the extrudable mass and of the extruded granule, and not
observing development of carbon dioxide in case of the dried
granule.
[0072] The latter was then characterized by carrying out the
analyses described in the characterization, obtaining the following
values:
[0073] glyphosate acid content: 72% by weight;
[0074] pH: 3.9;
[0075] solubility: complete without sediments;
[0076] residual moisture: 0.5%.
Example 2
[0077] The Example 1 was repeated but by using 276 grams of
ammonium sulphate previously milled instead of 776 grams.
[0078] While maintaining the mixture under mild stirring,
corresponding to 20 rev/minute, 1,500 g of tallow amine
(surfactant) Emulson.RTM. AG/PE 3SS (corresponding to a content of
15% based on the dry product and of 20.8% based on the acid) and 10
grams of antifoam agent Antifoam.RTM. SL were added.
[0079] The obtained mass was then subjected to mixing at the
maximum intensity corresponding to 100 rev/minute, with the aid of
a chopper for 3 minutes until obtaining an extrudable mixture.
[0080] The mixture had the consistence of a moist powder,
deformable by compression in a hand.
[0081] The mass temperature during said step maintained itself
lower than 35.degree. C.
[0082] Said mixture was then sent to the extruder described in the
Example 1 and extruded; the extruded product was then dried in the
dryer described in the Example 1 under the same conditions.
[0083] The whole process was monitored by carrying out some
solubility test of the mass to be extruded, of the extruded granule
and of the dried granule, observing development of carbon dioxide
in case of the mass to be extruded and of the extruded granule, and
not observing development of carbon dioxide in case of the dried
granule.
[0084] The dried granule was then characterized by carrying out the
analyses described in the characterization, obtaining the following
values:
[0085] glyphosate acid content: 72%;
[0086] pH: 3.9;
[0087] solubility: complete without sediments;
[0088] residual moisture: 0.5%.
Example 3
[0089] The Example 1 was exactly repeated except that the mixing of
step d) was carried out for 1 minute. The mass resulted extrudable
as in the Example 1 and the analyses carried out on the dried
granule gave the following values:
[0090] glyphosate acid content: 72%;
[0091] pH: 3.9;
[0092] solubility: complete without sediments;
[0093] residual moisture: 0.5%.
Example 4
Comparative
[0094] The Example 1 was exactly repeated except that the mixing of
step d) was carried out for about 30 minutes according to U.S. Pat.
No. 6,228,807.
It has been noticed: [0095] a temperature increase up to over
60.degree. C., due to the friction inside the mixer; [0096] the
complete salification of the glyphosate acid; [0097] the non
extrudability of said mass.
[0098] Furthermore also the subsequent cooling of the mass up to
room temperature by flowing of water in the jacket, carried out in
30 minutes, has not allowed to obtain an extrudable mass.
Example 5
Comparative
[0099] The Example 1 was repeated except that 1,776 grams of
ammonium sulphate were used and no surfactant was used.
[0100] Mixing was carried out at the maximum intensity,
corresponding to 100 rev/minute, with the aid of a chopper for 3
minutes; under these conditions it was not possible to obtain an
extrudable mixture.
[0101] The mass temperature during said step maintained itself
lower than 35.degree. C.
Example 6
Comparative
[0102] The Example 1 was repeated but in the absence of inert
agent, surfactant and antifoam agent.
[0103] The base and the acid were subjected to mixing at the
maximum intensity corresponding to 100 rev/minute, with the aid of
a chopper for 3 minutes; under these conditions it was not possible
to obtain an extrudable mixture.
[0104] The mass temperature during said step maintained itself
lower than 35.degree. C.
Example 7
Comparative
[0105] The Example 1 was repeated but by using 1,476 grams of
ammonium sulphate milled as in the Example 1 and 300 g of tallow
amine (surfactant) Emulson.RTM. AG/PE 3SS (corresponding to a
content of 3% with respect to the final composition and of 4.2%
with respect to the acid).
[0106] The obtained mass was then subjected to mixing at the
maximum intensity, corresponding to 100 rev/minute, with the aid of
a chopper for 3 minutes.
[0107] The obtained mass did not result extrudable in the extruder
described in the Example 1.
Example 8
[0108] 2,257 grams of an equimolar mixture of ammonium carbonate,
bicarbonate and carbamate, commercially known as Hartshorn salt
(E503) having ammonia titre of 31%, were cleared from lumps in a
Loedige mixer (Ploughshare type) equipped with chopper; 7,976 grams
of technical glyphosate having titre 96.9% and moisture 10%, 917
grams of ammonium sulphate previously milled by a rung mill were
then added and mixed for one minute.
[0109] While maintaining the mixture under mild stirring,
corresponding to 20 rev/minute, 1,500 g of tallow amine
(surfactant) Emulson.RTM. AG/PE 3SS (corresponding to a content of
15% based on the final composition and of 22% based on the acid)
and 10 grams of antifoam agent Antifoam.RTM. SL were added.
[0110] The obtained mass was then subjected to mixing at the
maximum intensity, corresponding to 100 rev/minute, with the aid of
a chopper for 3 minutes until obtaining an extrudable mixture.
[0111] The mixture had the consistence of a moist powder,
deformable by compression in a hand.
[0112] The mass temperature during said step maintained itself
lower than 35.degree. C.
[0113] Said mixture was then sent to the extruder described in the
Example 1 and extruded. The extruded product was then dried in the
dryer of the Example 1 and under the same conditions.
[0114] The whole process was monitored by carrying out some
solubility test of the mass to be extruded, of the extruded granule
and of the dried granule, observing development of carbon dioxide
in case of the mass to be extruded and of the extruded granule, and
not noticing development of carbon dioxide in case of the dried
granule.
[0115] The dried granule was then characterized by carrying out the
analyses described in the characterization, obtaining the following
values:
[0116] glyphosate acid content: 68%;
[0117] pH: 3.9;
[0118] solubility: complete without sediments;
[0119] residual moisture: 0.5%.
Example 9
[0120] 1,957 grams of an equimolar mixture of ammonium carbonate,
bicarbonate and carbamate, commercially known as Hartshorn salt
(E503) having ammonia titre of 31%, were cleared from lumps in a
Loedige mixer (Ploughshare type) equipped with chopper; 6,914 grams
of technical glyphosate having titre 96.9% and moisture 10%, 1,145
grams of ammonium sulphate previously milled by a rung mill were
then added and mixed for one minute.
[0121] While maintaining the mixture under mild stirring,
corresponding to 20 rev/minute, 2,000 g of tallow amine
(surfactant) Emulson.RTM. AG/PE 3SS (corresponding to a content of
20% based on the final composition and of 33.3% based on the acid)
and 10 grams of antifoam agent Antifoam.RTM. SL were added.
[0122] The obtained mass was then subjected to mixing at the
maximum intensity, corresponding to 100 rev/minute, with the aid of
a chopper for 3 minutes until obtaining an extrudable mixture.
[0123] The mixture had the consistence of a wet powder, deformable
by compression in a hand.
[0124] The mass temperature during said step maintained itself
lower than 35.degree. C.
[0125] Said mixture was then sent to the extruder described in the
Example 1 and extruded; the extruded product was then dried in the
dryer of the Example 1 and under the same conditions.
[0126] The whole process was monitored by carrying out some
solubility tests of the mass to be extruded, of the extruded
granule and of the dried granule, observing development of carbon
dioxide in case of the mass to be extruded and of the extruded
granule, and not noticing development of gas in case of the dried
granule.
[0127] The dried granule was then characterized by carrying out the
analyses described in the characterization, obtaining the following
values:
[0128] glyphosate acid content: 60%;
[0129] pH: 3.9;
[0130] solubility: complete without sediments;
[0131] residual moisture: 0.5%.
[0132] The obtained granule shows a high concentration of
glyphosate acid in combination with a high concentration of
surfactant, whose ratio is comparable to that found in commercial
products having a lower glyphosate titre, for example granules
containing 36% by weight of glyphosate.
* * * * *