U.S. patent application number 13/831311 was filed with the patent office on 2013-10-24 for additive containing n-(n-butyl)thiophosphoric triamide for urea-based fertilizer.
The applicant listed for this patent is Koch Agronomic Services, LLC. Invention is credited to Allen R. Sutton, Willis Thornsberry.
Application Number | 20130276495 13/831311 |
Document ID | / |
Family ID | 38309750 |
Filed Date | 2013-10-24 |
United States Patent
Application |
20130276495 |
Kind Code |
A1 |
Sutton; Allen R. ; et
al. |
October 24, 2013 |
ADDITIVE CONTAINING N-(N-BUTYL)THIOPHOSPHORIC TRIAMIDE FOR
UREA-BASED FERTILIZER
Abstract
A dry flowable additive for aqueous urea-based fertilizers made
of solid urea formaldehyde polymer (UFP), N-(n-butyl)
thiophosphoric triamide (NBPT), and, optionally, dicyandiamide
(DCD), wherein the liquid fertilizer containing the additive
provides reduced nitrogen loss from the soil. Optionally, the dry
additive may also be blended with molten or solid urea to form a
solid urea-based fertilizer with reduced nitrogen loss from the
soil.
Inventors: |
Sutton; Allen R.; (Corydon,
KY) ; Thornsberry; Willis; (Sturgis, KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Koch Agronomic Services, LLC |
Wichita |
KS |
US |
|
|
Family ID: |
38309750 |
Appl. No.: |
13/831311 |
Filed: |
March 14, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11652773 |
Jan 12, 2007 |
|
|
|
13831311 |
|
|
|
|
60758594 |
Jan 12, 2006 |
|
|
|
Current U.S.
Class: |
71/30 ;
71/28 |
Current CPC
Class: |
C05C 9/00 20130101; Y02P
60/218 20151101; C05C 9/005 20130101; C05C 9/02 20130101; Y02P
60/21 20151101; C05B 15/00 20130101; C05G 3/90 20200201 |
Class at
Publication: |
71/30 ;
71/28 |
International
Class: |
C05B 15/00 20060101
C05B015/00 |
Claims
1.-20. (canceled)
21. A fertilizer composition comprising: urea; and a composition
comprising: a. N-(n-butyl) thiophosphoric triamide (NBPT) in the
range of about 1 to 80 weight %, and b. solid urea formaldehyde
polymer (UFP) in the range of about 99 to 20 weight %, wherein the
UFP is a polymethyl urea resin.
22. The fertilizer composition of claim 21, wherein the fertilizer
composition further comprises dicyandiamide (DCD).
23. The fertilizer composition of claim 21, wherein the urea is
molten urea.
24. A fertilizer composition comprising: a. N-(n-butyl)
thiophosphoric triamide (NBPT) in the range of about 0.004 to 1.5
weight % of the total composition; b. dicyandiamide (DCD) in the
range of about 0.04 to 0.85 weight % of the total composition; c.
silicon dioxide in the range of about 0 to 0.03 weight % of the
total composition; d. solid urea formaldehyde polymer (UFP) in the
range of about 0.03 to 0.30 weight % of the total composition,
wherein the UFP is a polymethyl urea resin; and e. urea ammonium
nitrate (UAN) solution aqueous urea, or mixtures thereof, in the
range of about 98.0 to 99.9 weight % of the total composition.
25. The fertilizer composition of claim 24, wherein the urea is
UAN.
26. A method of preparing a fertilizer composition of claim 24,
wherein the NBPT and solid UFP is mixed with a urea to provide a
urea-based fertilizer having the following composition: a. NBPT in
the range of about 0.004 to 1.5 weight %; b. DCD in the range of
about 0.040 to 0.85 weight %; c. silicon dioxide in the range of
about 0 to 0.03 weight %; d. solid UFP in the range of about 0.03
to 0.30 weight %; and e. a urea in the range of about 98 to 99.5
weight %.
27. The method of claim 26, wherein the urea is UAN.
28. A composition comprising N-(n-butyl) thiophosphoric triamide
(NBPT) in about 1 to 80 weight % and urea formaldehyde polymer
(UFP) in about 99 to 20 weight %, wherein the NBPT is a solution or
suspension in an amide solvent and the UFP is a polymethyl urea
resin.
29. (canceled)
30. The composition of claim 28, wherein the composition further
comprises a dye product.
31. The composition of claim 28, further comprising an aqueous urea
solution.
32. The composition of claim 28, further comprising molten urea.
Description
FIELD OF THE INVENTION
[0001] The field of the invention is urea-containing fertilizers.
More specifically, this invention discloses a dry, flowable
additive containing N-(n-butyl) thiophosphoric triamide (NBPT),
solid urea-formaldehyde polymer (UFP), and, optionally,
dicyandiamide (DCD) which can be combined with a urea-based
fertilizer to prepare a fertilizer which provides reduced nitrogen
loss from the soil.
BACKGROUND OF THE INVENTION
[0002] Nitrogen is an important plant nutrient. In addition to
phosphorous, potassium, and other nutrients, nitrogen is needed to
support the growth and development of plant life. Some plants, such
as legumes, through a symbiotic relationship with Rhizobium
bacteria, fix elemental nitrogen from the atmosphere and fix this
nitrogen into the soil. However, most plants grown to produce human
and animal food require the use of nitrogen fertilizer in order to
sustain their agricultural production.
[0003] The most widely used and agriculturally important
high-analysis nitrogen fertilizer is urea, CO(NH.sub.2).sub.2.
While most of the urea currently produced is used as a fertilizer
in its granular form, urea-based fluid fertilizers are also well
known. As used herein, the term "fluid fertilizers" encompasses
liquid fertilizers, i.e. aqueous solutions of fertilizers, and
suspension fertilizers, i.e. fertilizer compositions which in
addition to water and water-soluble components also contain
insoluble components kept in suspension by a suspending agent, such
as clay. Suspension fertilizers are excellent carriers for
pesticides and micronutrients.
[0004] The most commonly known urea-based liquid fertilizer is an
aqueous solution of urea and ammonium nitrate, referred to in the
fertilizer trade as UAN solution. These fluid fertilizers are used
on a variety of crops, such as corn and wheat. When applied to
moist soil, the urea component of the fluid fertilizer becomes a
source of ammonia as a result of hydrolysis catalyzed by urease, an
enzyme produced by numerous fungi and bacteria. The process is
fully disclosed in U.S. Pat. No. 5,364,438, which is hereby
incorporated by reference. Unfortunately, the urease-catalyzed
hydrolysis often converts the urea to ammonia more quickly than it
can be absorbed by the soil, resulting in undesirable ammonia loss
to the atmosphere through a process called volatilization.
[0005] Urease inhibitors slow down the conversion of urea to
ammonia, extending the period of nitrogen release. One urease
inhibitor is N-(n-butyl) thiophosphoric triamide (NBPT). When
incorporated into a urea-based fertilizer, NBPT reduces the rate at
which urea is hydrolyzed to ammonia. This allows the nutrient
nitrogen to be available to the soil and plants over a longer
period of time. NBPT is widely recognized as an effective urease
inhibitor, but NBPT is notoriously difficult to handle, because
industrial grade NBPT is a waxy, sticky, heat-sensitive and
water-sensitive material. As a result, a solvent system was
disclosed in U.S. Pat. No. 5,364,438, that allowed the solution of
NBPT to be applied to UAN. However, this solution had stability
problems as well as problems in delivering and metering into fluid
fertilizer.
[0006] U.S. Pat. No. 5,352,265, which is hereby incorporated by
reference, discloses a granular fertilizer comprising about 90 to
99% urea, 0.02 to 0.5% NBPT and about 0 to 2.2% DCD. The NBPT is
added to molten urea as a concentrated solution in an amide
solvent. The DCD is added to the urea melt as a solid. This
granular product is made to apply directly to the field crop.
[0007] The present invention of a dry flowable additive, is
prepared by coating a solid urea-formaldehyde polymer (UFP) with a
solution or suspension of NBPT in a liquid solvent, preferably an
amide solvent. Optionally, the coated UFP may be blended with solid
DCD. Prior to application of the fertilizer to the field crop, the
dry flowable additive is blended with a UAN solution or aqueous
urea, to form the fluid urea-containing fertilizer composition, or
blended with solid or molten urea to form a solid urea-based
fertilizer. The present invention provides a fluid or solid
fertilizer composition that is easy to handle and stable when
stored.
SUMMARY OF THE INVENTION
[0008] All percentages are by weight, unless otherwise indicated.
The present invention is a fluid fertilizer composition, comprising
an aqueous solution of UAN or urea, NBPT and, optionally, DCD. A
dry flowable additive for the UAN or aqueous urea is prepared by
coating a solid UFP with a solution or suspension of NBPT in a
liquid solvent. The NBPT is present in the dry additive in the
amount of about 0.40 to 15.0%. The solid UFP is present in the
range of about 3.0 to 15.0%. Optionally, solid DCD can be blended
with this coated UFP in the range of 40.0 to 95.0%, and silicon
dioxide in the range of from about 0 to 3%. Prior to applying the
UAN or urea, the dry additive is blended with aqueous UAN or urea
in the range of about 0.4 to 2.5% additive to form the fluid
urea-containing fertilizer composition. Alternatively, the dry
flowable additive may also be added to molten urea or solid urea
and granulated to provide a dry fertilizer. The composition of the
present invention may be applied to a field crop to minimize the
undesired loss of ammonia nitrogen from surface-applied urea and
nitrogen loss in the soil due to leaching and denitrification of
nitrate nitrogen.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The term NBPT as used throughout this specification refers
not only to N-(n-butyl) thiophosphoric triamide in its pure form,
but also to industrial grades or other grades of the material which
may contain up to 50% impurities. The preferred NBPT is at least
50% pure, the most preferred NBPT is greater than 50% pure, in the
range of about 51 to 90% pure. The NBPT is present in the dry
flowable additive in the range of about 0.4 to 15.0%.
[0010] A NBPT solution or suspension in an amide solvent, such as
N-alkyl 2-pyrrolidone, is used to prepare the dry flowable additive
of the present invention. The solution or suspension contains
between about 30% and about 80% NBPT, and preferably between about
50% and about 75% NBPT. The NBPT solution may be prepared by
dissolving or suspending NBPT in a solvent selected from a group of
liquid amides such as an N-alkyl 2-pyrrolidone, or by adding the
N-alkyl 2-pyrrolidone into the NBPT production system in order to
produce an NBPT solution, rather than recover a waxy NBPT solid.
Alternatively, molten NBPT, without additional solvents, may be
used to coat the UFP in the present invention.
[0011] The solid UFP of the present invention is preferably a
polymethyl urea resin with approximately 0.6% reactive methylol
groups. It has primary particles of 0.1 to 0.15 .mu.m, forming
agglomerates of 3.5 to 6.5 .mu.m diameter on average. The preferred
solid UFP is marketed as PERGOPAK M.RTM. 2, a trademark of
Albemarle Corporation. The solid UFP is present in the dry flowable
additive in the range of about 3 to 15%. The most preferred solid
UFP is PERGOPAK M.RTM. 2 product or the unrefined pre-cursor to
PERGOPAK M.RTM. 2.
[0012] The optional DCD of the present invention has preferably a
particle range from about 50 to 350 .mu.m. The DCD is present in
the dry flowable additive in the range of about 40 to 95%. In a
further embodiment of the invention, the dry flowable additive may
contain from about 1.0 to 30.0% solid UFP and from about 99.0 to
70.0% DCD.
[0013] The balance of the composition consists primarily of water,
and an N-alkyl pyrrolidone may also be present in small quantities.
The composition may optionally also contain a suspending agent,
such as clay, as well as other additives, such as a herbicide, a
dye, an NBPT stabilizer, or a micronutrient. Silicon dioxide, a
flow agent, is optionally present in an amount of up to about 3% of
the dry flowable additive.
[0014] The dry, flowable additive prepared without the optional DCD
contains about 1 to 80% NBPT and about 99 to 20% solid UFP.
[0015] The dry flowable additive is added to the UAN solution,
aqueous urea, or solid or molten urea, in the range of about 0.1 to
5.0% additive in the final product. Preferably, the dry flowable
additive is added in the range of about 0.4 to 2.5% to fluid UAN or
urea solution, or blends thereof, to form a fluid fertilizer. The
fluid urea-based fertilizer of the present invention contains from
about 0.004 to 1.50% NBPT, from about 0.040 to 0.850% DCD, from
about 0.030 to about 0.30% UFP, and from about 99.9 to 98.0%
aqueous UAN. Optionally, the fertilizer can contain up to about
0.03% silicon dioxide. The aqueous UAN contains urea and ammonium
nitrate in concentration ranges of about 15 to 50%. A preferred
range is from about 25 to 40%.
[0016] The UAN-based fluid fertilizer composition of this invention
can be used in all agricultural applications in which UAN is
currently used. These applications include a very wide range of
crop and turf species, tillage systems, and fertilizer placement
methods.
[0017] The following example is to illustrate the invention and is
not present to limit the invention or claims in any manner.
EXAMPLE
[0018] The Example is a laboratory preparation of a dry flowable
additive composition.
[0019] 200 grams of 50% NBPT solution in N-alkyl 2-pyrrolidone was
added to 73.4 grams of solid UFP (PERGOPAK M.RTM. 2) and 0.5 grams
of a blue dye (FD & C blue #1). The mixture was blended until a
uniform mix was achieved as indicated by the distribution of the
blue color. This mixture was blended with 1270 grams DCD and
further blended to a uniform color to form the dry flowable
additive.
TABLE-US-00001 TABLE 1 Composition of Example 1 Component Mass (g)
% Component 50% NBPT solution 200.0 12.95 (6.47% NBPT) Solid UFP
73.4 4.75 Blue dye 0.50 0.03 DCD 1270.0 82.27 Total 1543.9
100.0
[0020] The dry flowable additive prepared in Example 1 was mixed
with aqueous UAN to form a fluid urea-based fertilizer and tested
for efficacy as an inhibitor of ammonia volatilization using test
methods known to those skilled in the art of volatilization
testing. A control sample did not contain NBPT, and the three
samples of the invention had NBPT at levels of 0.013%, 0.026% and
0.051% respectively in the final fluid UAN fertilizer composition.
It was found that the presence of NBPT was effective in reducing
ammonia loss, particularly at the 0.026% and 0.051% levels when
compared with fluid UAN fertilizer without NBPT (the control).
* * * * *