U.S. patent application number 13/088043 was filed with the patent office on 2012-04-19 for controlled release fertilizer with biopolymer coating and process for making same.
Invention is credited to Keith D. Cochran, Timothy G. Holt, Joseph M. Miller, Gregory S. Peeden, Taylor Pursell, Arthur R. Shirley, JR..
Application Number | 20120090366 13/088043 |
Document ID | / |
Family ID | 45932908 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120090366 |
Kind Code |
A1 |
Pursell; Taylor ; et
al. |
April 19, 2012 |
CONTROLLED RELEASE FERTILIZER WITH BIOPOLYMER COATING AND PROCESS
FOR MAKING SAME
Abstract
A controlled release fertilizer including a fertilizer granule,
having an outer surface, a coating of biopolymer composition on the
outer surface of the fertilizer granule, wherein the biopolymer
composition includes at least one biopolymer, and a process of
making the controlled release fertilizer including the steps of
screening fertilizer granules to a preselected granule size,
heating a biopolymer to become substantially fluid, and applying
the biopolymer onto the surface of the fertilizer granule to
produce a coating on the granule of a predetermined amount.
Inventors: |
Pursell; Taylor; (Mountain
Brook, AL) ; Shirley, JR.; Arthur R.; (Florence,
AL) ; Cochran; Keith D.; (Killen, AL) ;
Miller; Joseph M.; (Killen, AL) ; Holt; Timothy
G.; (Florence, AL) ; Peeden; Gregory S.;
(Killen, AL) |
Family ID: |
45932908 |
Appl. No.: |
13/088043 |
Filed: |
April 15, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61324948 |
Apr 16, 2010 |
|
|
|
Current U.S.
Class: |
71/28 ; 427/212;
71/11; 71/27 |
Current CPC
Class: |
C05G 5/37 20200201; C05G
5/37 20200201; C05G 5/37 20200201; C05G 5/38 20200201; C05G 5/38
20200201 |
Class at
Publication: |
71/28 ; 71/11;
71/27; 427/212 |
International
Class: |
C05C 9/00 20060101
C05C009/00; B05D 1/02 20060101 B05D001/02; C05D 9/02 20060101
C05D009/02 |
Claims
1. A controlled release fertilizer comprising: a fertilizer
granule, having an outer surface; a coating of biopolymer
composition on the outer surface of the fertilizer granule, wherein
said biopolymer composition includes at least one biopolymer.
2. The controlled release fertilizer of claim 1, wherein the
biopolymer is selected from the group consisting of polylactic
acid, polylactide, lactide, and oligomers thereof.
3. The controlled release fertilizer of claim 2, wherein the
biopolymer is polylactic acid oligomers.
4. The controlled release fertilizer of claim 1, wherein the amount
of biopolymer coating is 1.0 to 10 wt. %.
5. The controlled release fertilizer of claim 1, wherein the
biopolymer composition further includes at least one flow-sealant
modifier.
6. The controlled release fertilizer of claim 5, wherein the
flow-sealant modifier is selected from the group consisting of corn
syrup, high fructose syrups, cane syrup, rice syrup and glucose
syrup.
7. The controlled release fertilizer of claim 1, further comprising
a second outer coating of a water proof or resistant sealant
coating over the first coating of biopolymer composition resulting
in a twice coated fertilizer granule.
8. The controlled release fertilizer of claim 7, wherein the
sealant coating is selected from the group consisting of polyvinyl
acetate, waxes, polymer blends, paraffins and micro crystalline
waxes.
9. The controlled release fertilizer of claim 7, wherein the amount
of sealant coating is 0.05 to 5 wt. %.
10. The controlled release fertilizer of claim 1, wherein the
fertilizer granule includes a plant nutrient selected from the
group consisting of nitrogen, phosphorus and potassium
compounds.
11. The controlled release fertilizer of claim 10, wherein the
nitrogen compound is selected from the group consisting of urea,
ammonia, ammonium nitrate, ammonium sulfate, calcium nitrate,
diammonium phosphate, monoammonium phosphate, potassium nitrate and
sodium nitrate.
12. The controlled release fertilizer of claim 10, wherein the
phosphorous compound is selected from the group consisting of
diammonium phosphate, monoammonium phosphate, monopotassium
phosphate, dipotassium phosphate, tetrapotassium pyrophosphate, and
potassium metaphosphate.
13. The controlled release fertilizer of claim 10, wherein the
potassium compound is selected from the group consisting of
potassium chloride, potassium nitrate, potassium sulfate,
monopotassium phosphate, dipotassium phosphate, tetrapotassium
pyrophosphate, and potassium metaphosphate.
14. The controlled release fertilizer of claim 10, wherein the
fertilizer contains nitrogen, phosphorous and potassium compounds
in a N:P:K ratio selected from the group consisting of 29-3-4,
16-4-8, 10-10-10, 15-5-10, 15-0-15, 22-3-14, 20-28-5 and
12-6-6.
15. The controlled release fertilizer of claim 1, wherein the
fertilizer granule includes a macronutrient selected from the group
consisting of sulfur, calcium and magnesium and/or micronutrients
including boron, copper, iron, manganese, molybdenum and zinc.
16. A process of making a controlled release fertilizer comprising
the following steps: screening fertilizer granules to a preselected
granule size; heating a biopolymer to become substantially fluid;
and applying the biopolymer onto the surface of the fertilizer
granule to produce a coating on the granule of a predetermined
amount.
17. The process of claim 16, wherein the biopolymer coating, is
applied to the surface of the fertilizer granule surface by
pouring, hydraulic spraying or pneumatic atomized spraying.
18. The process of claim 16, wherein the amount of coating of
biopolymer is determined on a percent weight basis to result in a
range of 1.0 to 10 wt. %.
19. The process of claim 16, further comprising after the
biopolymer application step, the step of passing a cooling gas over
the coated granules to quickly set the biopolymer.
20. The process of claim 16, further comprising after the
biopolymer application step, a step of applying a parting agent to
the surface of the biopolymer coated fertilizer granules.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention is directed towards new and entirely
unexpected granular fertilizers and processes for making the
fertilizers, which provide controlled release of the fertilizer to
plants. The fertilizers may include additional advantageous agents
such as micro and macro nutrients and other agriculturally
beneficial materials. More particularly, the present invention is a
granular fertilizer coated with a biologically degradable polymer
(biopolymer). When such fertilizer is applied to the soil,
microorganisms will degrade the biopolymer coating over time,
releasing the fertilizer at a rate controlled by the amount, i.e.,
thickness of the biopolymer coating and chemical characteristics of
the biopolymer, as well as environmental conditions.
[0002] There are many slow and extended release fertilizers with
their nutrient release based on time and event related coating
failures or coating permeability. These fertilizers are influenced
by factors such as available soil water, fertilizer solubility,
microbial activity in the soil, and the ratio of surface area to
nutrient weight of the particle. Of these, the major commercial
products are sulfur coated urea, polymer coated ureas, and
urea-formaldehyde products such as methylene ureas.
[0003] Of the polymer coated fertilizers, almost all are dependent
on ambient temperature and moisture, and the thickness of the
coating. Most polymer coated fertilizers release nutrients by
physical diffusion through a semi-permeable polymer membrane, and
the release rate can be controlled by varying the composition and
thickness of the coating. The type of fertilizer substrate also may
influence the rate of nutrient (e.g., nitrogen) release. Nutrients
are released by physical diffusion through the polymer coating.
[0004] A more recent polymer coated fertilizer employs a reactive
layer coating which combines two reactive monomers as they are
simultaneously applied to the fertilizer substrate. These reactions
create an ultra-thin membrane coating, which controls nutrient
release by osmotic diffusion. The coating thickness determines the
diffusion rate and the duration of release for such reactive layer
coated products.
[0005] Polymer-sulfur coated fertilizers are hybrid products that
use a primary coating of sulfur and a secondary polymer coat. These
fertilizers were developed to deliver controlled-release
performance approaching that of solely polymer-coated fertilizers
but at a reduced cost. The nutrient-release mechanism of these
coated fertilizers is a combination of diffusion and capillary
action. Water vapor must first physically diffuse in through the
continuous polymer layer. The rate of diffusion is controlled by
the composition and thickness of the polymer film. Once at the
polymer-sulfur interface, the water penetrates the defects in the
sulfur coat through physical capillary action and begins to
dissolve the fertilizer core. The dissolved fertilizer then exits
the particle in reverse sequence.
[0006] Thermoplastic resins such as polyolefins, polyvinylidene
chloride, and copolymers may be employed to coat fertilizers.
Because the thermoplastic polymers used are highly impermeable to
water, release-controlling agents such as ethylene-vinyl acetate
and surfactants are typically added to the coating to obtain the
desired physical diffusion characteristics. Coating thicknesses are
essentially the same for all of such fertilizers with the release
being controlled by the chemical type of release-controlling agent
and amount of the agent.
BRIEF SUMMARY OF THE INVENTION
[0007] The fertilizers of the present invention are in a granular
form and provide controlled release of the fertilizer to plants.
The granular fertilizers have a coating of a biologically
degradable polymer (biopolymer). When such fertilizer is applied to
the soil, microorganisms metabolize or by some mechanism, disrupt
the biopolymer coating over time, releasing the fertilizer at a
rate controlled by the amount, i.e., thickness of the biopolymer
coating and chemical characteristics of the biopolymer, as well as
environmental conditions such as soil and/or air temperature and
available water. The fertilizers may include additional
advantageous agents such as micro and macro nutrients and other
agriculturally beneficial materials.
[0008] The presently employed coating of biopolymer(s) are
bio-based polymers, being derived from biomass such as from plants,
fungi and bacteria, and thus possessing potential efficiencies in
production from a wide availability and diversity of sources for
biomass. In particular, available corn-based polymers of polylactic
acid are made from the stock and fibrous parts of the corn plant
(not the kernel). Polylactic acid polymers may also be derived from
other carbohydrate loaded materials, for example, from wheat, sugar
and maize.
[0009] Polylactic acid (PLA) is a repeating chain of lactic acid
which when decomposing on or in the soil, undergoes a 2-step
degradation process. First, moisture and heat facilitate breaking
the PLA polymer chains and split them apart, creating smaller
polymer chains. Then microorganisms in the soil (and/or enzymes
excreted by them) consume (or deteriorate) the smaller polymer
fragments and lactic acid as nutrients. Lactic acid is widely found
in nature and so a large number of organisms metabolize lactic
acid. At a minimum, fungi and bacteria are involved in PLA
degradation. The end result of the process is carbon dioxide, water
and a tiny amount of organic residue. The degradation process is
dependent upon temperature and available water.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The present invention is a controlled release fertilizer
prepared by coating a granular fertilizer with one or more of a
family of biopolymer coating agents including polylactic acid,
polylactide, lactide, and/or an oligomer thereof, and processes for
making the controlled release fertilizer. The preferred coating
material is lactic acid oligomers, such as polylactic acid
oligomers. An example of such lactic acid oligomers is Olygos.TM.,
a bioresin produced by NatureWorks, LLC which has the following
properties for the specific product, Bioresin 120:
OLYGOS.TM. Bioresin 120 Technical Data Sheets
Typical (Average) Composition*
TABLE-US-00001 [0011] Bioresin 120 Method Lactyl-based species 85%
Titration Organic Acids 10% GC-MS Polyols 4.7% GC-MS Inorganic
Species .ltoreq.0.3% ICP-AES Typical Properties* Color Dark brown
to black Specific gravity 1.1 Specific heat capacity 2.3 J K.sup.-1
g.sup.-1 (0.56 BTU .degree. F..sup.-1 lb.sup.-1) Glass transition
temperature 25-40.degree. C. Pour point 120.degree. C. Viscosity at
210.degree. C. 98 cP Gross Calorific (Fuel) Value 19 kJ g.sup.-1
(8,300 BTU lb.sup.-1) Ash content 0.4% *Typical composition and
properties are not to be construed as specifications.
Bioresin 120 is an amorphous thermoplastic resin based on lactic
acid oligomers. It is derived primarily from annually renewable
resources. From NatureWorks, LLC, Minnetonka, Minn.,
[0012] Typical polylactic acid (PLA) coatings are modified by
adding 6.0% wt. (dry basis) corn syrup to the coating melt. This
modification improves the flow (less viscous) and sealing (more
water impermeable) properties of the PLA. Other such flow and
sealing modifiers may be employed, especially high fructose syrups,
and also cane syrup, rice syrup and glucose syrup.
[0013] In a further embodiment of the present invention, a water
proof or water resistant sealant is applied as a second, exterior
coating, after the PLA coating application. The sealant can be one
or more of the following: Evacote.RTM., Polyvinyl Acetate (PVA),
polymer blends, paraffins, micro crystalline waxes, and similar
materials. Evacote.RTM. is the preferred sealant, manufactured by
The International Group, Inc. Evacote.RTM. is specialty wax blends
that are used as hot melt coatings. The following are
characteristics of one Evacote.RTM. product:
Evacote.RTM. 7272
[0014] Physical Properties
TABLE-US-00002 ASTM SPECIFICATIONS TEST METHODS METHOD Minimum
Maximum TYPICAL Drop Melt Point .degree. F. (.degree. C.) D 127 --
-- 162 (72.2) Congealing Point .degree. F. (.degree. C.) D 938 151
(66.1) 161 (71.7) 156 (68.9) Thermosel Viscosity, cP @ 300.degree.
F. (148.9.degree. C.) D 3236 285 355 320 Thermosel Viscosity, cP @
275.degree. F. (135.degree. C.) D 3236 -- -- 440 Thermosel
Viscosity, cP @ 250.degree. F. (121.1.degree. C.) D 3236 -- -- 610
Color D 1500 -- -- L0.5 Needle Penetration, dmm @ 77.degree. F.
(25.degree. C.) D 1321 -- -- 7 Needle Penetration, dmm @ 90.degree.
F. (32.2.degree. C.) D 1321 -- -- 12
The typical range of amounts of biopolymer coating, such as PLA, is
1.0 to 10 wt. %, and more preferably the range is 1.0 to 5 wt. %.
The biopolymer coating thickness ranges from 50 to 500 microns.
[0015] The sealant coating amount is 0.05 to 5 wt. %, and more
preferably in the range of 0.5 to 2.0 wt. %.
[0016] Fertilizer granule sizes that can be coated range from 2.0
mm to 4.0 mm, and more preferably the size range is between 2.5 mm
and 3.3 mm.
[0017] The fertilizer may typically include sources of nitrogen,
phosphorus and/or potassium compounds.
[0018] The nitrogen compounds include urea, ammonia, ammonium
nitrate, ammonium sulfate, calcium nitrate, diammonium phosphate,
monoammonium phosphate, potassium nitrate and sodium nitrate.
[0019] The phosphorous compounds include diammonium phosphate,
monoammonium phosphate, monopotassium phosphate, dipotassium
phosphate, tetrapotassium pyrophosphate, and potassium
metaphosphate.
[0020] The potassium compounds include potassium chloride,
potassium nitrate, potassium sulfate, monopotassium phosphate,
dipotassium phosphate, tetrapotassium pyrophosphate, and potassium
metaphosphate.
[0021] Where the fertilizer contains nitrogen, phosphorous and
potassium compounds, the compounds are for example in a N:P:K ratio
selected from the group consisting of 29-3-4, 16-4-8, 10-10-10,
15-5-10, 15-0-15, 22-3-14, 20-28-5 and 12-6-6.
[0022] The fertilizer may further include macronutrients including
sulfur, calcium and magnesium and/or micronutrients including
boron, copper, iron, manganese, molybdenum and zinc.
[0023] In the process of making the present controlled release
fertilizer, the biopolymer coatings, including PLA coatings or PLA
type coatings, can be applied to the surface of fertilizer granules
surface by numerous methods including pouring, hydraulic spraying
or pneumatic atomized spraying. The initial fertilizer granule
sizes that can be coated range from 2.0 mm to 4.0 mm, and more
preferably the size range is between 2.5 mm and 3.3 mm. Fertilizer
granules are initially screened to obtain the desired size.
[0024] Typically, the biopolymer is heated to become substantially
fluid to a degree required for the aforementioned methods of
coating the biopolymer. The typical range of temperatures for
heating the biopolymer for coating the fertilizer granule is
330.degree. F. to 420.degree. F. The heated biopolymer is then
applied upon the fertilizer granule to produce a predetermined
amount, i.e., thickness of biopolymer coating, wherein the amount
of coating is determined on a percent weight basis to result in a
typical range of 1.0 to 10 wt. %, and more preferably a range of
1.0 to 5 wt. % biopolymer coating. The biopolymer coating thickness
ranges from 50 to 500 microns.
[0025] In another embodiment of the present process, at least one
flow-sealant modifier such as corn syrup, high fructose syrups,
cane syrup, rice syrup and glucose syrup, is blended with the
biopolymer before the biopolymer composition is applied to the
fertilizer granules.
[0026] In all types of application the biopolymer, e.g., PLA type
coatings are viscous and tend to form a mass of granules in the
processing equipment after the coating is applied. The coated
granule mass is quickly cooled to eliminate the tackiness of the
coating and thus reduce adhesion between the coated granules. When
allowed to cool at ambient conditions agglomerates tend to form
which have poor release characteristics.
[0027] Accordingly, the process of the present invention employs a
quick cooling method that sets the coating surface, thus
eliminating agglomerates and coating damage caused by granules
pulling apart. After the coating has been applied to the fertilizer
granule surface, a cool gas is passed over the granule surface
which quickly sets the coating surface. This gas can be nitrogen,
carbon dioxide, or refrigerated air. The temperature of the gas is
typically -100.degree. F. to +40.degree. F. During this cooling
phase the coating bed temperature ranges between 75.degree. F. and
150.degree. F., preferable less than 100.degree. F.
[0028] Instead of passing a cooling gas to quickly cool and set the
biopolymer coating, parting agents, such as talc, corn starch and
diatomaceous earth, have also been applied to eliminate the
tackiness from the coating. Parting agent content ranged from 2.5
wt. % to 7.4 wt. % and is applied to the surface of the coated
fertilizer granule after minimal cooling, immediately after
application of the biopolymer coating and then the biopolymer
coated fertilizer with surface coated parting agent is allowed to
finally cool.
[0029] In another embodiment of the present process, a water proof
or resistant sealant is applied over the first coating of
biopolymer composition resulting in a twice coated fertilizer
granule. The sealant is selected from the group consisting of
polyvinyl acetate, waxes, polymer blends, paraffins and micro
crystalline waxes. The sealant coating is applied to the surface of
the biopolymer coated fertilizer granules by pouring, hydraulic
spraying or pneumatic atomized spraying.
[0030] The present invention is demonstrated with reference to the
following examples, which are of an illustrative nature only and
which are to be construed as non-limiting.
EXAMPLES
[0031] The following compositions, described in Table 1, are
exemplary of the present invention.
TABLE-US-00003 TABLE 1 Product Samples Product Description And
Composition Coating Test 8 4.7% Olygos, 6.8% talc on urea Coating
Test 9 4.6% Olygos and corn syrup, 7.4% talc on urea Coating Test
13 4.9% Olygos and corn syrup, 2.5% DE, and 2% paraffin on urea
Coating Test 14 4.6% Olygos and corn syrup, 7.4% talc, and 2%
paraffin on urea Coating Test 15 4.7% Olygos, 6.8 talc, and 2%
paraffin on urea Coating Test 18 2.3% Olygos and corn syrup on urea
Coating Test 20 2.4% Olygos and corn syrup on urea Coating Test 21
2.3% Olygos and corn syrup, 1.5% Evacote 7089A on urea Coating Test
22 2.4% Olygos and corn syrup, 1.7% Evacote 7089A on urea Coating
Test 23 2.3% Olygos and corn syrup, 1.0% IGI 1339A on urea Coating
Test 24 2.4% Olygos and corn syrup, 1.0% IGI 1339A on urea Coating
Test 25 2.3% Olygos and corn syrup, 1.5% IGI R-4408A on urea
Coating Test 26 2.4% Olygos and corn syrup, 1.9% IGI R-4408A on
urea
Example 1
[0032] A bench scale test was conducted to produce test product
sample 9. The following materials were used:
[0033] 665 grams of granular urea (280 SGN)
[0034] 31.5 grams of Olygos.RTM. Bioresin 120
[0035] 3.5 grams of corn syrup (64.0% solids)
[0036] 56.1 grams talc
From the afore stated OLYGOS.TM. Bioresin 120 Technical Data
Sheets:
Typical (Average) Composition*
TABLE-US-00004 [0037] Bioresin 120 Method Lactyl-based species 85%
Titration Organic Acids 10% GC-MS Polyols 4.7% GC-MS Inorganic
Species .ltoreq.0.3% ICP-AES
[0038] The biopolymer, Olygos.RTM. and flow sealer modifier, corn
syrup were combined in a beaker and heated to 360.degree. F. on a
hot plate. Urea was placed in a bench scale rotary drum coater
(12'' diameter) equipped with anti slip rods and preheated to
208.degree. F. to produce fertilizer granules composed of urea.
After the Olygos and corn syrup mixture reached 360.degree. F. it
was poured over the rolling bed of urea granules and allowed to
mix. After the coating application was completed, the parting
agent, talc was applied to the rolling bed. The bed was allowed to
cool to 120 F then removed from the coating drum.
Example 2
[0039] A bench scale test was conducted to produce test product
sample 22. The following materials were used:
[0040] 672 grams of granular urea (280 SGN)
[0041] 25.2 grams of Olygos Bioresin 120
[0042] 2.8 grams of corn syrup (64.0% solids)
[0043] 9.2 grams of Evacote.RTM.
[0044] Olygos and corn syrup were combined in a beaker and heated
to 355.degree. F. on a hot plate. Urea was placed in a bench scale
rotary drum coater (12'' diameter) equipped with anti slip rods and
preheated to 200.degree. F. After the Olygos and corn syrup mixture
reached 355.degree. F. it was poured over the rolling bed of urea
granules and allowed to mix. After the coating application was
completed, nitrogen was sparged into the rolling bed to quickly
cool the coating. The bed was cooled to 70.degree. F.
[0045] Evacote.RTM. was heated to 185.degree. F. in a beaker on a
hot plate prior to pouring on to the rolling bed. Evacote is
described above and is a water resistant sealant applied as a
second, exterior coating, after the biopolymer coating application.
The bed was allowed to mix for 1 to 2 minutes while maintaining the
bed temperature at 110 to 120.degree. F. Compressed air was blown
into the drum to cool the bed to 100.degree. F. before
discharging.
Test Results
[0046] The sample products were tested for controlled release of
urea fertilizer. The test results are shown in Table 2 and
expressed as the percent of urea retained. The percent of urea
retained was determined using Method N-500.00 test method as
described below.
[0047] In the tested Samples that include a second coating sealant
(Samples 13-15, and 21-26), the sealants are paraffin wax,
Evacote.RTM. 7089A, IGI.RTM. 1339A and IGI.RTM. R-4408A. The
characteristics of Evacote.RTM. 7089A have been stated above. The
characteristics of IGI.RTM. 1339A and IGI.RTM. R-4408A are the
following:
IGI.RTM. 1339A
[0048] IGI.RTM. 1339A is a paraffinic Fischer-Tropsch wax with low
isomer content and high melting point.
Physical Properties
TABLE-US-00005 [0049] ASTM SPECIFICATIONS TEST METHODS METHOD
Minimum Maximum TYPICAL Congealing Point .degree. F. (.degree. C.)
D 938 156 (68.9) 165 (73.9) 160 (71.1) Kinematic Viscosity, cSt @
212.degree. F. (100.degree. C.) D 445 5.5 6.5 6.0 Oil Content, Wt %
D 721 -- 0.7 0.4 Saybolt Color D 6045 +28 -- +30 Odor D 1833 -- 1 0
Needle Penetration, dmm @ 77.degree. F. (25.degree. C.) D 1321 --
-- 10 Needle Penetration, dmm @ 100.degree. F. (37.8.degree. C.) D
1321 -- -- 17 Note: Physical properties for which ONLY a typical
value is listed are included as additional information but may not
be printed on the COA.
IGI.RTM. R-4408A
Physical Properties
TABLE-US-00006 [0050] ASTM SPECIFICATIONS* TEST METHODS METHOD
Minimum Maximum TYPICAL Drop Melt Point .degree. F. (.degree. C.) D
127 160 (71.1) 170 (76.7) 165 (73.9) Kinematic Viscosity, cSt @
212.degree. F. (100.degree. C.) D 445 7.5 9.0 8.5 Flash Point
(P.M.), .degree. F. (.degree. C.) D 93 500 (260) -- 525 (274) ASTM
Color D 6045 -- -- 4.5 Needle Penetration, dmm @ 77.degree. F.
(25.degree. C.) D 1321 -- 20 18 *Tentative
IGI.RTM. R-4408A and IGI.RTM. 1339A are manufactured by The
International Group, Inc., Titusville, Pa.
[0051] Paraffin wax is C.sub.20H.sub.42 to C.sub.40H.sub.82 and is
in a solid state at room temperature.
TABLE-US-00007 TABLE 2 Coating Conditioner Sealant % Urea Test # %
% % Sealant Type Retained* Coating 4.6 7.4 0 None 22.7 Test 9
Coating 4.9 2.5 2 Paraffin Wax 30.0 Test 13 Coating 4.6 7.4 2
Paraffin Wax 73.6 Test 14 Coating 4.7 6.8 2 Paraffin Wax 92.4 Test
15 Coating 2.3 0.0 0 None 32.4 Test 18 Coating 2.4 0.0 0 None 38.0
Test 20 Coating 2.3 0.0 1.5 Evacote 91.4 Test 21 7089A Coating 2.4
0.0 1.7 Evacote ~95 Test 22 7089A Coating 2.3 0.0 1.0 IGI 1339A
19.8 Test 23 Coating 2.4 0.0 1.0 IGI 1339A ~95 Test 24 Coating 2.3
0.0 1.5 IGI R-4408A 83.2 Test 25 Coating 2.4 0.0 1.9 IGI R-4408A
72.8 Test 26 *% Urea Retained as determined using Method N-500.00
test method.
Method N-500.00
Automated Preparation for the Determination of Controlled Release
Nitrogen
Scope:
[0052] This is a standard analytical preparation for the
determination of controlled release nitrogen components in
fertilizer samples and may be used as a preparation for methods
N-400.10--"Kjeldahl Ammoniacal Nitrogen", N-400.20--"Kjeldahl Water
Soluble Organic Nitrogen", N-400.40--"Automated Ammoniacal
Nitrogen", N-400.50--"Automated Urea Nitrogen", and
N-400.60--"Automated Nitrate Nitrogen". When samples prepared by
this method and method N-400.00--"Break-Down Nitrogen Preparation",
are run by the methods listed above, and in conjunction with method
N-100.00--"Total Nitrogen Determination", the controlled release
nitrogen component can be calculated.
Principle:
[0053] The automated preparation for the determination of
controlled-release nitrogen is achieved by adding a proportioning
pump to the system outlined in AOAC (15th edition) 945.01 and
970.04 to pull water through the column at 2 mL/minute and
discarding the separatory funnel.
Reagents and Chemicals:
[0054] D.I. Water 20-25.degree. C.
Apparatus and Equipment:
[0055] Balance, accuracy to 0.001 g. [0056] Chromatography columns,
1.0 cm.times.30 cm as needed [0057] Flask, 250 mL volumetric.
[0058] Glass or Polyester Wool [0059] Mounting rack [0060]
Proportioning pump [0061] Pump tubes--2 cc/minute as needed [0062]
Support clamps as needed [0063] Tubing-- 1/32 I.D., connectors, and
glassware as needed
Sample Preparation Procedure:
Column Preparation:
[0063] [0064] 1. Reduce an unground sample (a micro-splitter is
suggested) to obtain two sub samples of approximately 3 g. [0065]
2. Weigh the two unground subsamples and place them in 1 cm dia.
chromatography columns containing a small glass or polyester wool
plug.
System Start-Up:
[0065] [0066] 1. Place 250 mL of D.I. water in a 250 mL volumetric
flask for each sample column. [0067] 2. Clamp columns to mounting
rack and connect tubing. [0068] 3. Pour water from flask into
column until water level is about 50 mm above the top of the sample
(adjust water level so that when the drip starts the water level is
25 mm above the top of the sample). [0069] 4. Place cap on column
and the tubing connected to the cap, into the flask with the
remaining water. [0070] 5. Place the end of the tubing coming from
the proportioning pump into an empty volumetric flask. [0071] 6.
Set timer for 2 hours. [0072] NOTE: At this point your connections
should run as follows; water to column cap on column--column bottom
to proportioning pump to empty flask. [0073] 7. Turn proportioning
pump on and check water level--adjust as in step 3 above.
System Shut-Down:
[0073] [0074] 1. When all water has been pumped from column remove
flask containing extract, bring final volume to 250 mL using D.I.
water and shake. [0075] 2. Remove columns and clean. [0076] 3.
Clean tubing with 0.1N HCl and D.I. water. [0077] 4. The following
determinations are performed on the extract-nitrate nitrogen,
ammoniacal nitrogen and urea nitrogen. [0078] NOTE: The extract
from this method may need to be diluted.
Calculations:
Symbols for Determinations on Ground Samples:
[0079] A=Ammoniacal Nitrogen
N=Nitrate Nitrogen
I=Insoluble Nitrogen
S=Soluble Non-Urea Nitrogen
T=Total Nitrogen
UA=Urea Nitrogen+Ammoniacal Nitrogen
U=Urea Nitrogen
WA=Water Soluble Nitrogen+Ammoniacal Nitrogen
W=Water Soluble Nitrogen
Symbols for Determinations on Extract of Unground Samples:
[0080] NOTE: All results from determinations on extracts of
unground samples are the average of both sides of the final
split.
[0080] A'=Ammoniacal Nitrogen
N'=Nitrate Nitrogen
I'=Insoluble Nitrogen
S'=Soluble Non-Urea Nitrogen
T'=Total Nitrogen
UA'=Urea Nitrogen+Ammoniacal Nitrogen
U'=Urea Nitrogen
WA'=Water Soluble Nitrogen+Ammoniacal Nitrogen
W'=Water Soluble Nitrogen
Calculations of Symbols:
[0081] UA-A=U
WA-A=W
W-U=S
UA'-A'=U'
WA'-A'=W'
W'-U'=S'
Calculation of Controlled-Release Nitrogen:
1. Coated Urea
[0082] Controlled-Release=W-U' [0083] Alternate Calculation
[0083] Controlled-Release=T-U'
Calculation of Liquid Controlled-Release Nitrogen:
2. Water Soluble Non Urea Nitrogen
[0084] Controlled-Release=WA-UA'or
Controlled-Release=(N+WA)-(N'+UA)'
3. Controlled-Release Nitrogen:
[0085] CR=T-(N'+UA') [0086] Alternate Calculation
[0086] Controlled-Release=(N+WA+I)-(N'+UA')
REFERENCES
AOAC 15th Edition
[0087] 1. Method 945.01 "Nitrogen (Water Insoluble) in
Fertilizers--Method I". [0088] 2. Method 970.04 "Nitrogen (Water
Insoluble) in Fertilizers--Method II".
[0089] While only a few exemplary embodiments of this invention
have been described in detail, those skilled in the art will
recognize that there are many possible variations and modifications
which may be made in the exemplary embodiments while yet retaining
many of the novel and advantageous features of this invention.
Accordingly, it is intended that the following claims cover all
such modifications and variations.
* * * * *