CA1047272A - Slow release fertilizer composition - Google Patents
Slow release fertilizer compositionInfo
- Publication number
- CA1047272A CA1047272A CA207,726A CA207726A CA1047272A CA 1047272 A CA1047272 A CA 1047272A CA 207726 A CA207726 A CA 207726A CA 1047272 A CA1047272 A CA 1047272A
- Authority
- CA
- Canada
- Prior art keywords
- fertilizer
- matrix
- slow release
- composition
- release fertilizer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Fertilizers (AREA)
Abstract
SLOW RELEASE FERTILIZER COMPOSITION
ABSTRACT OF THE DISCLOSURE
A slow release fertilizer composition compris-ing a vulcanizable elastomer matrix material and a water soluble fertilizer. The water soluble fertilizer is dis-tributed throughout the matrix in which the fertilizer is substantially insoluble. In the presence of the water the fertilizer is slowly and continuously leached from the matrix.
ABSTRACT OF THE DISCLOSURE
A slow release fertilizer composition compris-ing a vulcanizable elastomer matrix material and a water soluble fertilizer. The water soluble fertilizer is dis-tributed throughout the matrix in which the fertilizer is substantially insoluble. In the presence of the water the fertilizer is slowly and continuously leached from the matrix.
Description
S. M. Bille-N. F. Cardarelli 104~27Z l-l , .:
; - 2 -This invention relates to a slow release fertil~
izer and to a process for its preparation.
Nitrogen, phosphorus and potassium are the pri~
mary essential elements for plant growth, and commercially available fertilizers invariably comprise either or both an organic and an inorganic compound containing one or more of these elements in ~ome form. Agronomically, most commercially available fertilizer materials are marked by ~,.
one notably detrimental phy~ical property - high water solubility. Thus, treatment of plants with highly water soluble fertilizer materials, particularly nitrogen-containing, can be undesirable because the fertilizers are readily solubilized, thereby releasing nutrients in the soil at high concentrations. This results in luxury con-sumption and nutrient imbalances. If the release of nutr~-ents were controlled to more closely match actual plant :., ; re~uirements, a number of adva~tages would accrue. Eval-uated from the viewpoint of plant physiology, controlled-` release fertilizers, as compared to many conventional ; 20 fertilizers, maintain a more optimum concentration of ` nutrient in the root zone over a longer part of the plant growth period. Particularly in the case of turfgrass, controlled-release fertilizers applied in a single appli-cation provide a more even rate of growth than split applications of a soluble fertilizer at comparable rates.
- Other advantages of controlled-release fertilizers are minimization of nutrient losses due to runoff or ;
iO47272 S.M. Bille - N.F. Cardarelli . .
s volatilization, reduction of application costs through re-duction in frequency of applications and prevention of veg-etation burning or seedling damage.
Many attempts to control nutrient release to plants have been made with varying degrees of success.
These efforts have focused on two broad areas: (1) devel-opment of polymeric or discrete chemical compounds that have limited water solubility, and (2) altering soluble compounds in some manner to retard their release in the soil-~solution, as by coatings or matrices which are water-insoluble. A number of patents have issued on the results of these effort~, many of which are directed to matrices for fertilizers.
U. S. Patents 3,417,181 and 3,639,583 disclose the use of a vulcanizable elastomeric matrix for the con-trolled release of toxicants. ~owever, the mechanism of rèlease of the active agent in the~e patents depends upon a solubility equilibrium system requiring that the toxi-,. .
cants be soluble in the matrix but have only limited water solubility. Fertilizers, on the other hand, are normally insoluble in elastomeric matrices and highly soluble in wa~er. Moreover, because of elastomer solubility require-ments, the elastomeric matrix of the aforementioned patents must be present in large proportions, well over 80% of the - 25 weight of the product. In the case of fertilizers, cost among other considerations would normally preclude the use of a product containing such large proportions of matrix.
10~7272 proportions of matrix. Coatings or matrices intended to slow or control the release of fertilizers should be effective at relatively low percentages in order to provide the greatest fertilizer benefit and the lowest cost per unit weight of product.
We have discovered that a vulcanizable elastomeric material forms a highly effective matrix for the slow release of water soluble fertilizers. -The proportion of active agent in the matrix, the manner of incorporation of the fertilizer in the matrix and its method of release is totally different from that set forth in the aforementioned patents. In the compositions of the invention, the fertilizers are distributed throughout the elastomeric matrix in which the fertilizer is insoluble and they are slowly and continu- -ously released from the matrix in the presence of water by a leaching process.
Accordingly~ the present invention provides a slow release fertil-izer composition comprising a water permeable~ biodegradable~ organic vulcanizable elastomeric matrix material and a water soluble organic or inorganic fertilizer distributed throughout said matrix, said matrix being present in an amount of from 5 to 50% of the fertilizer weight, said fertilizer being substantially insoluble in the matrix and adapted in the presence of water to be slowly leached therefrom.
The present invention also provides a process of preparing a slow release fertilizer composition comprising blending a water soluble organic or inorganic fertilizer with from 5 to 50% by weight of the fertilizer of a water permeable, biodegradable~ organic ~ulcanizable elastomeric material to distribute the fertilizer throughout the matrix, forming shaped rods, sheets or other forms of the blended composition, vulcanizing and comminuting the ` shaped composition to produce a finely divided composition in which the fertilizer is substantially insoluble in the matrix and adapted in the pre-sence of water to be slowly leached therefrom.
The vulcaniza~le elastomers use~ul in the invention retain higher . ~
: - -~ 10~7Z72 loadings of active ingredients than the toxicants of the aforementioned patents because the fertilizer or other active ingredient is retained in the matrix as discrete particles rather than in solution. When placed in the soil, water molecules from the external environment gradually permeate the surface area of the elastomeric pellets or granules and contact the water soluble fertilizer molecules. The latter pass into solution and move out of the elastomer body in accordance with the law of solution kinetics. Removal of ` the fertilizer molecules or aggregates of molecules leads to the growth of a fine pore structure within the pellet, thus facilitating water contact with internal fertilizer . .
.:
:
"'" ' ;: `
` ' :`~
,,.,~
. . , 1~ - 4a -S.M. Bille - N.F. Cardarelli 1 ~047~72 1-l with internal fertilizer molecules, which in turn pass through the pore structures into the elastomer - water ~ "--interface and hence to the external environment.
Water permeation of the elastomer base, pore growth and solution and movement of the fertilizer are ~`
time dependent occurrences so that the 1098 of fertilizer is continuous and 810w. Noreovex, the rate of fertilizer release may be adjusted to achieve a specific desired level by choice of add tives, process of compounding and u~e of vulcanization.
The matrices useful in the practice of the in-vention are organic elastomeric materials capable of being '~ crosslinked or vulcanized. A particularly preferred class 't~ of rubbers useful as matrice~ are natural rubber, synthetic ; 15 natural rubbers (polyisoprene), cis-polybutadiene rubber, ethylene-propylene and styrene-butadiene copolymers. The foregoing elastomers are water-permeable, biodegradable, ;, ;; permit high loading of fertilizer and are relatively inex-~f.` pensive. Other useful elastomers such as butyl rubber (isobutylene/isoprene copolymer) and ethylene-propylene-~
- dicyclopentadiene terpolymers may also be used. Polyure-thane and polychloroprene type elastomers are also useful ~; although their cost is somewhat greater than those mentioned above. The matrix may be used in an amount corresponding .~;
to 5 to 50% of the fertilizer weight. The crosslinking of vulcanization is carried out in a manner well known in the rubber compounding art. Measured amounts of sulfur, sulfur - bearing materials, metal oxides, peroxides, amines or other ~ S. M. Bille/N. F. Cardarelli ~
~047272 known vulcanization elements, as they are known to the trade, are added and the formulations are then exposed to a time-temperature cycle to crosslink the elastomeric molecules which in turn provide the proper matrix-~
geometry.
Virtually any water soluble organic or inorganic fertilizer material may be used in the invention. Exam-; ples are urea, ammonium sulfate, ammonium nitrate, monoammonium phosphate, potassium chloride, potassium sulfate and other well known plant nutrients.
In addition to the elastomer, the fertilizer and the vulcanizing agent(s), a number of additives may be pre-sent in the formulations. Powdered carbon or carbon black is instrumental in controlling the release rate of the active agent. This additive is entrained within the matrix and serves to impede the progress of ingressing water and the flow of water solution of the agent outward, carbon blacks vary in geometry from course to very fine, the more highly structured blacks, ranging from 20 to 40 millimicrons in diameter being superior in usage. The carbon black may be used in amounts of 1 to 25 parts by weight per hundred parts of elastomer.
Other additives may be added to the elastomer/
fertilizer systems in order to enhance specifically de-sirable properties. Such additives include organic sub-; stances that aid in the retardation of pore structure growth, thus slowing the leaching system, such as waxes and oils; or other polymers that in effect "coat" the , agent retarding solubilization in water. This latter "
S. M. Bille/N.F. Cardarelli- 1-1 class of materials is typified by polymers that bond through H-O}~ attraction with urea - such as polyvinyl acetate, polyamides, cellulose acetate and polyvinyl alcohols. In addition, lubricants such as stearic acid, anti-oxidants such as phenyl-beta-naphthylamine and cure accelerators such as benzothiazole disulfide, mercaptobenzothiazole and tetramethylthiuram disulfide may also be added.
The compositions may be formulated by known ' 10 rubber blending techniques in conventional rubber pro-,......................................................................... .
cessing equipment. Mixing may be carried out on two-roll rubber mills or internal-type mixers. The compo-sitions may then be sheeted off of a rubber mill or a rubber calender or extruded as a rod of varying diameter.
It may then be vulcanized by placing between heated plates, at the desired time - temperature, e.g. from 240 to 310F for from 15 minutes to 2 hours, or by pass-ing through a hot air oven at the stated conditions.
After vulcanization, the sheets, rods or other shapes may be chopped or otherwise comminuted into pellets, granules, powder flakes or other finely divided form.
The formulations are then ready for application to the soil, normally at a rate providing from 40 to 250 lbs/acre of nitrogen.
~i The following examples illustrate the practice :
; of the invention. All parts are by weight unless other-'~ wise identified.
~ .
~ - 7 -~ -~"
: .
lV4~Z7z S. M. Bille~N. F. Cardarelli - 1-1 Example 1 The folluwing formulation was prepared, based upon parts by weight of each ingredient.
Natural Rubber 100 Sulfur 1.5 Stearic Acid .2 Benzothiazole Disulfide0.~
Mercaptobenzothiazole0.7 Carbon Black 15 Zinc Oxide Urea 150 The natural rubber was masticated and banded on a rubber mill and the remaining materiala added gradually while the milling continued. The remaining materials were added in the following order: carbon black, stearic acid, sulfur and zinc oxide, urea and finally the sulfide and thiazole accelerators. The resulting formulation was then vulcanized between heated plates at 240 for 60 minutes and the resulting sheets were chopped into pellets.
.~
~ 20 Examples 2 - 4 i The following additional formulations were pre-pared in accordance with the procedure of Example 1.
Example 2 used Ameripol-SN-600* (synthetic polyisoprene rubber) as the matrix; Example 3 used Ameripol-CB-220*
(ci~polybutadiene rubber); and Example 4 used Ameripol-1510* lnon-pigmented cold styrene-butadiene rubber).
*Trademarks 10'~72~Z
S. M. Billie/N. F. Cardarelli ~
_ 9 _ - , Example 2 Example 3 Example 4 .
Styrene-butadiene 100 Polyisoprene 100 Cis-polybutadiene 100 Sulfur 1.5 1.5 1.5 Stearic Acid 0.2 Benzothiazole Disulfide 0.7 Mercaptobenzothiazole O.7 1.O 1.0 Phenyl-beta-napthylamine 1.0 Carbon Black 20 ; Carbon Black 20 20 ~ .
~" Zinc Oxide 1.0 ~i 15 Urea 130 150 150 i~ A series of greenhouse tests were run on the coated products of Examples 1 - 4. The tests were run on plots of Windsor Kentucky bluegrass seedlings con-~ taining adequate levels of phosphorous and potassium.
;~1 20 These evaluations were conducted on all plots at the r~ same time to eliminate variablessuch as light intensity, ~ air temperatures and the like from affecting the results.
"
~ In addition, for comparison, a gras~ plot was also given a ;i; single initial application with straight urea. A final control plot was left untreated. Table I sets forth fresh weight of grass clippings on the indicated day after treatment. Clipping weights are a conventional indicator of nutrient uptake by a test plant, and therefore of , fertilizer release charact:eristics.
;, 7} _ 9 _ 1047272 s . M. Bille-N . F . Cardarelli , o ~n g C w w x w u~
'.' ~ ~
o t~ ~ 1~
,, ~ D ~
,~, dP
, ~.
I a~ ~ o o w u~ I~
.i I . . . ~ z:
~ ~ w o~
,'": tD 11 .
, ,:~ ~ .-¦ ¦ o n ¦
",,, , , , , , , o~ ~ It~. -.. ~ ~D C~ :
.. ,`, ,4 1~ , '.',. .~
..
~ W ~ ~ ~ ~ l_ ,., ~ ~ ~ ~ o ':~ ' ' :' o CO
.,, , Ul ~ Ul ~ Ul ,,, o~ n ~D
~, ~ ~
,; co a~ co ~ ~ O ~
C~ ~o I_ : ~ . . Ul : ~ o o~ ~ x o a ;~:' ~ o .
., 1~ a~
u~ ul '. ......
-- W OD W ~ a~ ~I
D CO ~ a~
:
. ~
:'' -- S. N. Bille/N. F. Cardarelli - 1-1 Table II shows the results of color observa-tions of the same test plots at the indicated intervals after treatment. The results are on a O to 10 scale with the best color being 10.
, ~
:
..
1047272 ~. N. F~ille/N. F. Cardarelli . ~ ~
' 0 ~5 X ~,~ X ~D
. . ~ w ~ ~_ . _ .P
I O~ ~ O O
I a~ ~ ~ o c~
~,' u~ ~ w ~0 (D o . . . _ ,.' ~
,' . ~ ~3 . ~ ~
o ,' ~, i, w 0~ co oO ~o co ~
CO ~ ~D
~ D W
~. oo co ao w D 9 ~
.'. ~,, ~ DO ~D a~
.'.' Vl ~ n ; ~ o ~n ~.~ ~ n _~
~ O CO ~n ~ .
'' '',"
: - - . . .. .
~~ ~' S. ii. ~ille~. F. Cardarelli ~
.
Table III records the results of turf quality of the same test plots at the indicated intervals. Turf quality ~as evaluated on a 1 to 10 scale with best quality being 1.
' .
,, . . .
, :
" .
`'','"
., .:., . .~
~ ~ 1047272 S. !~. I3ille/~1. F. Cardarelli o ~
~ c ~ 3 u~
o ~s X X ~ X
.: i~
~ w ~ I_ _ .P ~ .~ 1~ N H O
I ~ o w a~ ~ ~ o co 3~;~
v~ w o~ -J t~
_._.,. _ ~' . tr t`~ tr3 t`' I`~ w _ _ ~' Vl l.Jl Vl Vl 1~
`, ~ W ~ W ~ ~ W
;~ ~ ~ ~ l--.
.~ ~ W .P ~ ~
~ W ~ to ~Jl . .
... Vl ~ W W N ~ Vl Ul ~ N ~ W W ¦ a~
.:' Vl X Ul . .
; 1047~2 '. S. M. Bille/N. F. Cardarelli - 1-1 ., :
Example 5 (SE-36D) A formulation was prepared from the following constituents in parts by weight:
Ethylene proplene dimer (Epcar* 5465) 100 . 5 Sulfur 0.75 Stearic Acid 0.5 . Mercaptobenzothiazole 0.75 , Carbon Black 20 Tetramethylthiuram disulfide 0.4 , 10 Urea 100 t The formulation was mixed and w lcanized as set forth in Example 1. Field tests of this composition : at 5 lbs./1,000 sq. ft. application rate indicated very good turf color and essentially no phytotoxicity.
Example 6 ~;; A formulation was prepared and vulcanized as ;, .~ in Example 1 containing (NH412SO4 as the fertilizer source in place of urea. The elastomer was the ethylene-. propylene dimer of Example 5. The formulation was as ... 20 follow~:
.. Ethylene-Propylene Dimer 100 ' Sulfur Mercaptobenzothiazole ,.. ~
Carbon Black 15 ' 25 Zinc Oxide 1.5 ;; Ammonium Sulfate 100 ,""~
, . .
. *Trademark . _ ~5 _ ,:
S. M. Bille-N. F. Cardarelli 1047Z72 1-l ~
Example 7 Example 6 was repeated substituting 100 parts of the styrene-butadiene rubber used in Example 4 as the elas-tomer. The formulation was otherwise the same.
.~ -S Example 8 Example 6 was repeated substituting 100 parts of natural rubber as the elastomer.
Release rate studies were performed on the ammonium sulfate compositions of example 6 to 8 to determine the percent of nitrogen loss at intervals over a thirteen week period. The release rate tests were conducted by immersing duplicate samples of the compositions tested in water for specified periods of time and then analyzing the water for the amount of nitrogen present. The results of these tests are set forth in Table IV.
., .
r ..~
.... .
. .
:, ~ ~ 104'~2~2 S. M. Bille/N. F. Cardarelli ~n .' , ..... _ =z I î~ ~
w' ~ ~o ~ ~D ~1 W W~ ~ l_ l , ~ .. ` ....... w . ~ , ._ _ O~P
w o 1~ al :~ ~ t~ C
:', O ~ ~I tD ~ U~
,, ~n o ~ co O
u',''~' ~ o ~ _ ~
.~ _ OO
,' w 1~- --~,: ~ co co t~
o _ .' : . .
S. M. Bille-N. F. Cardarelli - 18 ~
The test results of Table IV show that after a relatively high initial release rate, the materials level off to a fairly continuous nitrogen release over testing - period. The compositions incorporating ammonium sulfate in natural rubber (Example 8) display the most steady and con-tinuous release during the 13 week period.
Test results similar to those described above were , carried out with ammonium nitrate as the fertilizer in place of ammonium sulfate. The results indicate that am-monium nitrate acts similarly to ammonium sulfate in the compositions of the inventions.
',,: :- .
.. :
,,, .~ ., .
, ;~.,:, .. . .
;',. :
i ...
..
~. . .
. .
~, '' ~'
; - 2 -This invention relates to a slow release fertil~
izer and to a process for its preparation.
Nitrogen, phosphorus and potassium are the pri~
mary essential elements for plant growth, and commercially available fertilizers invariably comprise either or both an organic and an inorganic compound containing one or more of these elements in ~ome form. Agronomically, most commercially available fertilizer materials are marked by ~,.
one notably detrimental phy~ical property - high water solubility. Thus, treatment of plants with highly water soluble fertilizer materials, particularly nitrogen-containing, can be undesirable because the fertilizers are readily solubilized, thereby releasing nutrients in the soil at high concentrations. This results in luxury con-sumption and nutrient imbalances. If the release of nutr~-ents were controlled to more closely match actual plant :., ; re~uirements, a number of adva~tages would accrue. Eval-uated from the viewpoint of plant physiology, controlled-` release fertilizers, as compared to many conventional ; 20 fertilizers, maintain a more optimum concentration of ` nutrient in the root zone over a longer part of the plant growth period. Particularly in the case of turfgrass, controlled-release fertilizers applied in a single appli-cation provide a more even rate of growth than split applications of a soluble fertilizer at comparable rates.
- Other advantages of controlled-release fertilizers are minimization of nutrient losses due to runoff or ;
iO47272 S.M. Bille - N.F. Cardarelli . .
s volatilization, reduction of application costs through re-duction in frequency of applications and prevention of veg-etation burning or seedling damage.
Many attempts to control nutrient release to plants have been made with varying degrees of success.
These efforts have focused on two broad areas: (1) devel-opment of polymeric or discrete chemical compounds that have limited water solubility, and (2) altering soluble compounds in some manner to retard their release in the soil-~solution, as by coatings or matrices which are water-insoluble. A number of patents have issued on the results of these effort~, many of which are directed to matrices for fertilizers.
U. S. Patents 3,417,181 and 3,639,583 disclose the use of a vulcanizable elastomeric matrix for the con-trolled release of toxicants. ~owever, the mechanism of rèlease of the active agent in the~e patents depends upon a solubility equilibrium system requiring that the toxi-,. .
cants be soluble in the matrix but have only limited water solubility. Fertilizers, on the other hand, are normally insoluble in elastomeric matrices and highly soluble in wa~er. Moreover, because of elastomer solubility require-ments, the elastomeric matrix of the aforementioned patents must be present in large proportions, well over 80% of the - 25 weight of the product. In the case of fertilizers, cost among other considerations would normally preclude the use of a product containing such large proportions of matrix.
10~7272 proportions of matrix. Coatings or matrices intended to slow or control the release of fertilizers should be effective at relatively low percentages in order to provide the greatest fertilizer benefit and the lowest cost per unit weight of product.
We have discovered that a vulcanizable elastomeric material forms a highly effective matrix for the slow release of water soluble fertilizers. -The proportion of active agent in the matrix, the manner of incorporation of the fertilizer in the matrix and its method of release is totally different from that set forth in the aforementioned patents. In the compositions of the invention, the fertilizers are distributed throughout the elastomeric matrix in which the fertilizer is insoluble and they are slowly and continu- -ously released from the matrix in the presence of water by a leaching process.
Accordingly~ the present invention provides a slow release fertil-izer composition comprising a water permeable~ biodegradable~ organic vulcanizable elastomeric matrix material and a water soluble organic or inorganic fertilizer distributed throughout said matrix, said matrix being present in an amount of from 5 to 50% of the fertilizer weight, said fertilizer being substantially insoluble in the matrix and adapted in the presence of water to be slowly leached therefrom.
The present invention also provides a process of preparing a slow release fertilizer composition comprising blending a water soluble organic or inorganic fertilizer with from 5 to 50% by weight of the fertilizer of a water permeable, biodegradable~ organic ~ulcanizable elastomeric material to distribute the fertilizer throughout the matrix, forming shaped rods, sheets or other forms of the blended composition, vulcanizing and comminuting the ` shaped composition to produce a finely divided composition in which the fertilizer is substantially insoluble in the matrix and adapted in the pre-sence of water to be slowly leached therefrom.
The vulcaniza~le elastomers use~ul in the invention retain higher . ~
: - -~ 10~7Z72 loadings of active ingredients than the toxicants of the aforementioned patents because the fertilizer or other active ingredient is retained in the matrix as discrete particles rather than in solution. When placed in the soil, water molecules from the external environment gradually permeate the surface area of the elastomeric pellets or granules and contact the water soluble fertilizer molecules. The latter pass into solution and move out of the elastomer body in accordance with the law of solution kinetics. Removal of ` the fertilizer molecules or aggregates of molecules leads to the growth of a fine pore structure within the pellet, thus facilitating water contact with internal fertilizer . .
.:
:
"'" ' ;: `
` ' :`~
,,.,~
. . , 1~ - 4a -S.M. Bille - N.F. Cardarelli 1 ~047~72 1-l with internal fertilizer molecules, which in turn pass through the pore structures into the elastomer - water ~ "--interface and hence to the external environment.
Water permeation of the elastomer base, pore growth and solution and movement of the fertilizer are ~`
time dependent occurrences so that the 1098 of fertilizer is continuous and 810w. Noreovex, the rate of fertilizer release may be adjusted to achieve a specific desired level by choice of add tives, process of compounding and u~e of vulcanization.
The matrices useful in the practice of the in-vention are organic elastomeric materials capable of being '~ crosslinked or vulcanized. A particularly preferred class 't~ of rubbers useful as matrice~ are natural rubber, synthetic ; 15 natural rubbers (polyisoprene), cis-polybutadiene rubber, ethylene-propylene and styrene-butadiene copolymers. The foregoing elastomers are water-permeable, biodegradable, ;, ;; permit high loading of fertilizer and are relatively inex-~f.` pensive. Other useful elastomers such as butyl rubber (isobutylene/isoprene copolymer) and ethylene-propylene-~
- dicyclopentadiene terpolymers may also be used. Polyure-thane and polychloroprene type elastomers are also useful ~; although their cost is somewhat greater than those mentioned above. The matrix may be used in an amount corresponding .~;
to 5 to 50% of the fertilizer weight. The crosslinking of vulcanization is carried out in a manner well known in the rubber compounding art. Measured amounts of sulfur, sulfur - bearing materials, metal oxides, peroxides, amines or other ~ S. M. Bille/N. F. Cardarelli ~
~047272 known vulcanization elements, as they are known to the trade, are added and the formulations are then exposed to a time-temperature cycle to crosslink the elastomeric molecules which in turn provide the proper matrix-~
geometry.
Virtually any water soluble organic or inorganic fertilizer material may be used in the invention. Exam-; ples are urea, ammonium sulfate, ammonium nitrate, monoammonium phosphate, potassium chloride, potassium sulfate and other well known plant nutrients.
In addition to the elastomer, the fertilizer and the vulcanizing agent(s), a number of additives may be pre-sent in the formulations. Powdered carbon or carbon black is instrumental in controlling the release rate of the active agent. This additive is entrained within the matrix and serves to impede the progress of ingressing water and the flow of water solution of the agent outward, carbon blacks vary in geometry from course to very fine, the more highly structured blacks, ranging from 20 to 40 millimicrons in diameter being superior in usage. The carbon black may be used in amounts of 1 to 25 parts by weight per hundred parts of elastomer.
Other additives may be added to the elastomer/
fertilizer systems in order to enhance specifically de-sirable properties. Such additives include organic sub-; stances that aid in the retardation of pore structure growth, thus slowing the leaching system, such as waxes and oils; or other polymers that in effect "coat" the , agent retarding solubilization in water. This latter "
S. M. Bille/N.F. Cardarelli- 1-1 class of materials is typified by polymers that bond through H-O}~ attraction with urea - such as polyvinyl acetate, polyamides, cellulose acetate and polyvinyl alcohols. In addition, lubricants such as stearic acid, anti-oxidants such as phenyl-beta-naphthylamine and cure accelerators such as benzothiazole disulfide, mercaptobenzothiazole and tetramethylthiuram disulfide may also be added.
The compositions may be formulated by known ' 10 rubber blending techniques in conventional rubber pro-,......................................................................... .
cessing equipment. Mixing may be carried out on two-roll rubber mills or internal-type mixers. The compo-sitions may then be sheeted off of a rubber mill or a rubber calender or extruded as a rod of varying diameter.
It may then be vulcanized by placing between heated plates, at the desired time - temperature, e.g. from 240 to 310F for from 15 minutes to 2 hours, or by pass-ing through a hot air oven at the stated conditions.
After vulcanization, the sheets, rods or other shapes may be chopped or otherwise comminuted into pellets, granules, powder flakes or other finely divided form.
The formulations are then ready for application to the soil, normally at a rate providing from 40 to 250 lbs/acre of nitrogen.
~i The following examples illustrate the practice :
; of the invention. All parts are by weight unless other-'~ wise identified.
~ .
~ - 7 -~ -~"
: .
lV4~Z7z S. M. Bille~N. F. Cardarelli - 1-1 Example 1 The folluwing formulation was prepared, based upon parts by weight of each ingredient.
Natural Rubber 100 Sulfur 1.5 Stearic Acid .2 Benzothiazole Disulfide0.~
Mercaptobenzothiazole0.7 Carbon Black 15 Zinc Oxide Urea 150 The natural rubber was masticated and banded on a rubber mill and the remaining materiala added gradually while the milling continued. The remaining materials were added in the following order: carbon black, stearic acid, sulfur and zinc oxide, urea and finally the sulfide and thiazole accelerators. The resulting formulation was then vulcanized between heated plates at 240 for 60 minutes and the resulting sheets were chopped into pellets.
.~
~ 20 Examples 2 - 4 i The following additional formulations were pre-pared in accordance with the procedure of Example 1.
Example 2 used Ameripol-SN-600* (synthetic polyisoprene rubber) as the matrix; Example 3 used Ameripol-CB-220*
(ci~polybutadiene rubber); and Example 4 used Ameripol-1510* lnon-pigmented cold styrene-butadiene rubber).
*Trademarks 10'~72~Z
S. M. Billie/N. F. Cardarelli ~
_ 9 _ - , Example 2 Example 3 Example 4 .
Styrene-butadiene 100 Polyisoprene 100 Cis-polybutadiene 100 Sulfur 1.5 1.5 1.5 Stearic Acid 0.2 Benzothiazole Disulfide 0.7 Mercaptobenzothiazole O.7 1.O 1.0 Phenyl-beta-napthylamine 1.0 Carbon Black 20 ; Carbon Black 20 20 ~ .
~" Zinc Oxide 1.0 ~i 15 Urea 130 150 150 i~ A series of greenhouse tests were run on the coated products of Examples 1 - 4. The tests were run on plots of Windsor Kentucky bluegrass seedlings con-~ taining adequate levels of phosphorous and potassium.
;~1 20 These evaluations were conducted on all plots at the r~ same time to eliminate variablessuch as light intensity, ~ air temperatures and the like from affecting the results.
"
~ In addition, for comparison, a gras~ plot was also given a ;i; single initial application with straight urea. A final control plot was left untreated. Table I sets forth fresh weight of grass clippings on the indicated day after treatment. Clipping weights are a conventional indicator of nutrient uptake by a test plant, and therefore of , fertilizer release charact:eristics.
;, 7} _ 9 _ 1047272 s . M. Bille-N . F . Cardarelli , o ~n g C w w x w u~
'.' ~ ~
o t~ ~ 1~
,, ~ D ~
,~, dP
, ~.
I a~ ~ o o w u~ I~
.i I . . . ~ z:
~ ~ w o~
,'": tD 11 .
, ,:~ ~ .-¦ ¦ o n ¦
",,, , , , , , , o~ ~ It~. -.. ~ ~D C~ :
.. ,`, ,4 1~ , '.',. .~
..
~ W ~ ~ ~ ~ l_ ,., ~ ~ ~ ~ o ':~ ' ' :' o CO
.,, , Ul ~ Ul ~ Ul ,,, o~ n ~D
~, ~ ~
,; co a~ co ~ ~ O ~
C~ ~o I_ : ~ . . Ul : ~ o o~ ~ x o a ;~:' ~ o .
., 1~ a~
u~ ul '. ......
-- W OD W ~ a~ ~I
D CO ~ a~
:
. ~
:'' -- S. N. Bille/N. F. Cardarelli - 1-1 Table II shows the results of color observa-tions of the same test plots at the indicated intervals after treatment. The results are on a O to 10 scale with the best color being 10.
, ~
:
..
1047272 ~. N. F~ille/N. F. Cardarelli . ~ ~
' 0 ~5 X ~,~ X ~D
. . ~ w ~ ~_ . _ .P
I O~ ~ O O
I a~ ~ ~ o c~
~,' u~ ~ w ~0 (D o . . . _ ,.' ~
,' . ~ ~3 . ~ ~
o ,' ~, i, w 0~ co oO ~o co ~
CO ~ ~D
~ D W
~. oo co ao w D 9 ~
.'. ~,, ~ DO ~D a~
.'.' Vl ~ n ; ~ o ~n ~.~ ~ n _~
~ O CO ~n ~ .
'' '',"
: - - . . .. .
~~ ~' S. ii. ~ille~. F. Cardarelli ~
.
Table III records the results of turf quality of the same test plots at the indicated intervals. Turf quality ~as evaluated on a 1 to 10 scale with best quality being 1.
' .
,, . . .
, :
" .
`'','"
., .:., . .~
~ ~ 1047272 S. !~. I3ille/~1. F. Cardarelli o ~
~ c ~ 3 u~
o ~s X X ~ X
.: i~
~ w ~ I_ _ .P ~ .~ 1~ N H O
I ~ o w a~ ~ ~ o co 3~;~
v~ w o~ -J t~
_._.,. _ ~' . tr t`~ tr3 t`' I`~ w _ _ ~' Vl l.Jl Vl Vl 1~
`, ~ W ~ W ~ ~ W
;~ ~ ~ ~ l--.
.~ ~ W .P ~ ~
~ W ~ to ~Jl . .
... Vl ~ W W N ~ Vl Ul ~ N ~ W W ¦ a~
.:' Vl X Ul . .
; 1047~2 '. S. M. Bille/N. F. Cardarelli - 1-1 ., :
Example 5 (SE-36D) A formulation was prepared from the following constituents in parts by weight:
Ethylene proplene dimer (Epcar* 5465) 100 . 5 Sulfur 0.75 Stearic Acid 0.5 . Mercaptobenzothiazole 0.75 , Carbon Black 20 Tetramethylthiuram disulfide 0.4 , 10 Urea 100 t The formulation was mixed and w lcanized as set forth in Example 1. Field tests of this composition : at 5 lbs./1,000 sq. ft. application rate indicated very good turf color and essentially no phytotoxicity.
Example 6 ~;; A formulation was prepared and vulcanized as ;, .~ in Example 1 containing (NH412SO4 as the fertilizer source in place of urea. The elastomer was the ethylene-. propylene dimer of Example 5. The formulation was as ... 20 follow~:
.. Ethylene-Propylene Dimer 100 ' Sulfur Mercaptobenzothiazole ,.. ~
Carbon Black 15 ' 25 Zinc Oxide 1.5 ;; Ammonium Sulfate 100 ,""~
, . .
. *Trademark . _ ~5 _ ,:
S. M. Bille-N. F. Cardarelli 1047Z72 1-l ~
Example 7 Example 6 was repeated substituting 100 parts of the styrene-butadiene rubber used in Example 4 as the elas-tomer. The formulation was otherwise the same.
.~ -S Example 8 Example 6 was repeated substituting 100 parts of natural rubber as the elastomer.
Release rate studies were performed on the ammonium sulfate compositions of example 6 to 8 to determine the percent of nitrogen loss at intervals over a thirteen week period. The release rate tests were conducted by immersing duplicate samples of the compositions tested in water for specified periods of time and then analyzing the water for the amount of nitrogen present. The results of these tests are set forth in Table IV.
., .
r ..~
.... .
. .
:, ~ ~ 104'~2~2 S. M. Bille/N. F. Cardarelli ~n .' , ..... _ =z I î~ ~
w' ~ ~o ~ ~D ~1 W W~ ~ l_ l , ~ .. ` ....... w . ~ , ._ _ O~P
w o 1~ al :~ ~ t~ C
:', O ~ ~I tD ~ U~
,, ~n o ~ co O
u',''~' ~ o ~ _ ~
.~ _ OO
,' w 1~- --~,: ~ co co t~
o _ .' : . .
S. M. Bille-N. F. Cardarelli - 18 ~
The test results of Table IV show that after a relatively high initial release rate, the materials level off to a fairly continuous nitrogen release over testing - period. The compositions incorporating ammonium sulfate in natural rubber (Example 8) display the most steady and con-tinuous release during the 13 week period.
Test results similar to those described above were , carried out with ammonium nitrate as the fertilizer in place of ammonium sulfate. The results indicate that am-monium nitrate acts similarly to ammonium sulfate in the compositions of the inventions.
',,: :- .
.. :
,,, .~ ., .
, ;~.,:, .. . .
;',. :
i ...
..
~. . .
. .
~, '' ~'
Claims (12)
1. A slow release fertilizer composition comprising a water permeable, biodegradable, organic vulcanizable elastomeric matrix material and a water soluble organic or inorganic fertilizer distributed throughout said matrix, said matrix being present in an amount of from 5 to 50% of the fertilizer weight, said fertilizer being substantially insoluble in the matrix and adapted in the presence of water to be slowly leached therefrom.
2. The slow release fertilizer composition of Claim 1 in which the matrix is vulcanized.
3. The slow release fertilizer composition of Claim 1 in which the matrix is an elastomer selected from the group consisting of natural rubber, synthetic natural rubbers (polyisoprene), cispolybutadiene rubber, ethylene-propylene polymers and styrene-butadiene copolymers.
4. The slow release fertilizer composition of Claim 3 in which the matrix is natural rubber.
5. The slow release fertilizer composition of Claim 1 in which the matrix contains from 1 to 25 parts by weight per hundred parts of elastomer of carbon black.
6. The slow release fertilizer composition of Claim 1 in which the fertilizer is nitrogen-containing fertilizer.
7. The slow release fertilizer composition of Claim 6 in which the fertilizer is urea.
8. The slow release fertilizer composition of Claim 6 in which the fertilizer is ammonium sulfate.
9. The slow release fertilizer composition of Claim 6 in which the fertilizer is ammonium nitrate.
10. A process of preparing a slow release fertilizer composition comprising blending a water soluble organic or inorganic fertilizer with from 5 to 50% by weight of the fertilizer of a water permeable, biodegradable, organic vulcanizable elastomeric material to distribute the fertilizer throughout the matrix, forming shaped rods, sheets or other forms of the blended composition, vulcanizing and comminuting the shaped com-position to produce a finely divided composition in which the fertilizer is substantially insoluble in the matrix and adapted in the presence of water to be slowly leached therefrom.
11. The process of Claim 10 in which the matrix is vulcanizes with sulfur.
12. The process of Claim 10 in which from 1 to 25 parts by weight per hundred parts of elastomer of carbon black is blended with the fertilizer and elasto-meric matrix.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US39112773A | 1973-08-24 | 1973-08-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047272A true CA1047272A (en) | 1979-01-30 |
Family
ID=23545367
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA207,726A Expired CA1047272A (en) | 1973-08-24 | 1974-08-23 | Slow release fertilizer composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1047272A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4549897A (en) * | 1981-08-20 | 1985-10-29 | Petroliam Nasional Berhad | Protein degraded pre-vulcanized natural rubber coated slow release fertilizers |
| US4670039A (en) * | 1983-03-07 | 1987-06-02 | Metropolitan Mosquito Control District | Timed release fertilizer composition and means |
| US4732762A (en) * | 1983-03-07 | 1988-03-22 | Metropolitan Mosquito Control District | Timed release pest control composition and means |
| GB2305914B (en) * | 1995-10-06 | 1999-12-15 | Chown Peter A C | A slow release fertilizer product |
-
1974
- 1974-08-23 CA CA207,726A patent/CA1047272A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4549897A (en) * | 1981-08-20 | 1985-10-29 | Petroliam Nasional Berhad | Protein degraded pre-vulcanized natural rubber coated slow release fertilizers |
| US4670039A (en) * | 1983-03-07 | 1987-06-02 | Metropolitan Mosquito Control District | Timed release fertilizer composition and means |
| US4732762A (en) * | 1983-03-07 | 1988-03-22 | Metropolitan Mosquito Control District | Timed release pest control composition and means |
| GB2305914B (en) * | 1995-10-06 | 1999-12-15 | Chown Peter A C | A slow release fertilizer product |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110809569B (en) | Synergistic fertilizer with urease inhibitor and nitrification inhibitor separated in the same granule | |
| CN110770195B (en) | Enhanced fertilizer with embedded powder composition | |
| US3232740A (en) | Agricultural nutrient containing urea | |
| EP3415488B1 (en) | Preparations with improved urease-inhibiting properties and urea-based fertilizers containing those preparations | |
| US3388989A (en) | Fertilizer composition consisting of urea, a urease inhibitor, and a hydrocarbon binder | |
| CN110770194A (en) | Synergistic fertilizer with urease inhibitor and nitrification inhibitor in separate granules | |
| CA1129609A (en) | Method for oil-treating insoluble sulfur | |
| US2703276A (en) | Soil-conditioning fertilizer | |
| US3206297A (en) | Slow release fertilizers | |
| CA1047272A (en) | Slow release fertilizer composition | |
| PL200257B1 (en) | Agricultural composition and conditioning agent | |
| CA2225155C (en) | Particulate urea with mineral filler incorporated for hardness | |
| US6558445B2 (en) | Dry fertilizer compositions and method for making the same | |
| WO2016115552A1 (en) | Flowable mixture including elemental sulfur and hydrated clay and method for producing the same | |
| US5174806A (en) | Neutral solid fertilizer | |
| CN105777406A (en) | Pesticide and fertilizer mixture containing clothianidin | |
| US4913725A (en) | Granular fertilizer compositions | |
| US3168437A (en) | Stabilized granular gypsum-pesticidal composition and method of preparation | |
| US3125434A (en) | Hjsox | |
| Varadachari et al. | Slow-release and controlled-release nitrogen fertilizers | |
| US3689551A (en) | Odor free non-caking conditioned urea composition and process of preparing same | |
| US2893166A (en) | Stabilized soil and method of producing it with quaternary nitrogen salt | |
| US3174844A (en) | Method of fertilizing turf with a non-burning fertilizer | |
| KR101584321B1 (en) | Fertilizer and its manufacturing method includes sulfur | |
| CA1043927A (en) | Low temperature plasticizer composition for natural and synthetic butadiene-styrene rubber |