CA1188123A - Controlled release particulate fertilizer composition - Google Patents
Controlled release particulate fertilizer compositionInfo
- Publication number
- CA1188123A CA1188123A CA000408379A CA408379A CA1188123A CA 1188123 A CA1188123 A CA 1188123A CA 000408379 A CA000408379 A CA 000408379A CA 408379 A CA408379 A CA 408379A CA 1188123 A CA1188123 A CA 1188123A
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- CA
- Canada
- Prior art keywords
- urea
- fertilizer composition
- fertilizer
- nitrogen
- carrier
- 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.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C9/00—Fertilisers containing urea or urea compounds
- C05C9/02—Fertilisers containing urea or urea compounds containing urea-formaldehyde condensates
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Fertilizers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A controlled release particulate fertllizer composition prepared by the reaction of area and formaldehyde comprising polymeric nitrogen in the form of methylene area polymers of varying chain length. The majority of the polymeric nitrogen consists of short chain polymers selected from the group consisting of methylene diurea, dimethylene triurea and mixtures thereof and the average degree of polymerization of area and formaldehyde is qreater than 1.5. The fertilizer compositions combine safety and high levels of plant nutrient efficiency.
A controlled release particulate fertllizer composition prepared by the reaction of area and formaldehyde comprising polymeric nitrogen in the form of methylene area polymers of varying chain length. The majority of the polymeric nitrogen consists of short chain polymers selected from the group consisting of methylene diurea, dimethylene triurea and mixtures thereof and the average degree of polymerization of area and formaldehyde is qreater than 1.5. The fertilizer compositions combine safety and high levels of plant nutrient efficiency.
Description
3 H. ~. ~oertz-2~3 BA~YGROUND ~ THE INVENTIO~
.
This invention relates tG a particulate fertilizer composition prepared by the reaction o~ urea and formaldehy~e.
Urea-formaldehyde condensation prcducts are widely used as slow or controlled release nitrogen fertilizers. The condensation products contain rnethylene urea polymers Gf varying chain length.
The higher methylene urea polymers have limited scluhility in 50il .
_ . . _ ,, . . - . . . . _ ,, ... , _ .
solution and hence serve to prolong the release of nitrcgen.' The method of nitrogen release is normally thought tG be by microbial ~ecomposition. ~ost of the literature relating to such products has emphasized the impGrtance of the longer chain water inscluble polymers which have been cGnsidered safer and desirable fGr slcw release. The products hav traditionally been characterized in terms of the water' insolubility of their nitrogen fractions. The 1980 standards of the Association of American Plant Food Control ~fficials (~APFCO), ~or example, requires that any fertilizer labeled as urea-formaldehyde, or ureaform, must have at least ~%
of its n-trogen in water-ir.s~luble,form with an activity,index Gf at least 40 (Official Publication, AAPFCO, No. 3i, Rules N-24, 2Q ~-~.5, 1980). Activity Index (AI) is the percent of the cGld water insoluhle nitro~en (CWIN) which is soluble in hot water:
AI = --~wINH-I- x 100 ~H~IN is hGt water insoluble nitrogen) The longer chain water insoluble polymers are, in fact, much ~5 less agrGnomically active than the shorter,chain polymersO
~enerally, the efficiency of plant utilization decreases as the methylene urea polymer chain increases. It has been known for some time that a portion of the cold water insoluble nitrG~en fractiGn ~C~IN) has a very low mineralization rate and is very inefficient l~&~ f3 H- ~- GGertz-2/3 .
in terms of its practical us~ to a plant. ~his ine~ficien~
fr~ction is the hot water insoluble ni~rogen (R~ cccrdingly, the official definition of AAPFCO limi~s the allowable presence of this ~WI~ fraction. ~owever, even with this limitatiGn, a substantiai portion of the nitrogen (3~%-50~) may still be Present in this ~ery inefficient hot water insoluble ~orm. Attempts have been made to increase the efficiency of the product by mixing the - - urea-formaldehyde reaction products with soluble nitrogen sources such as urea. This has the effect of decreasing the HWIN fraction, ln increasing the -available nitrogen and providing "quick release"
properties to the mixture. ~owever, it also adds suhstantially to the "burn" or phytotc~ic pctential of the mixture. It is important to note that urea is present in substantially all urea-formaldehyde fertilizer com~ositions from incomplete or equilibrium reactions during polymerization. Such unreacted urea has the same agronomic response and tolerance as commercially available urea which is deliberately added.
The manufacture of slow release urea-fcrmaldehyde reaction products for fertilizer applications requires ccnsiderable skill to prcduce the proper degree of polymerization required to achieve the desired fertilizer characteristic5~ Normally, they are prepared by first reacting urea and for~aldehyde at elevat~d temperatures in an alkaline solution to produce methylol ureas. The reaction mixture is then acidified which causes the methylcl ureas tc polymerize
.
This invention relates tG a particulate fertilizer composition prepared by the reaction o~ urea and formaldehy~e.
Urea-formaldehyde condensation prcducts are widely used as slow or controlled release nitrogen fertilizers. The condensation products contain rnethylene urea polymers Gf varying chain length.
The higher methylene urea polymers have limited scluhility in 50il .
_ . . _ ,, . . - . . . . _ ,, ... , _ .
solution and hence serve to prolong the release of nitrcgen.' The method of nitrogen release is normally thought tG be by microbial ~ecomposition. ~ost of the literature relating to such products has emphasized the impGrtance of the longer chain water inscluble polymers which have been cGnsidered safer and desirable fGr slcw release. The products hav traditionally been characterized in terms of the water' insolubility of their nitrogen fractions. The 1980 standards of the Association of American Plant Food Control ~fficials (~APFCO), ~or example, requires that any fertilizer labeled as urea-formaldehyde, or ureaform, must have at least ~%
of its n-trogen in water-ir.s~luble,form with an activity,index Gf at least 40 (Official Publication, AAPFCO, No. 3i, Rules N-24, 2Q ~-~.5, 1980). Activity Index (AI) is the percent of the cGld water insoluhle nitro~en (CWIN) which is soluble in hot water:
AI = --~wINH-I- x 100 ~H~IN is hGt water insoluble nitrogen) The longer chain water insoluble polymers are, in fact, much ~5 less agrGnomically active than the shorter,chain polymersO
~enerally, the efficiency of plant utilization decreases as the methylene urea polymer chain increases. It has been known for some time that a portion of the cold water insoluble nitrG~en fractiGn ~C~IN) has a very low mineralization rate and is very inefficient l~&~ f3 H- ~- GGertz-2/3 .
in terms of its practical us~ to a plant. ~his ine~ficien~
fr~ction is the hot water insoluble ni~rogen (R~ cccrdingly, the official definition of AAPFCO limi~s the allowable presence of this ~WI~ fraction. ~owever, even with this limitatiGn, a substantiai portion of the nitrogen (3~%-50~) may still be Present in this ~ery inefficient hot water insoluble ~orm. Attempts have been made to increase the efficiency of the product by mixing the - - urea-formaldehyde reaction products with soluble nitrogen sources such as urea. This has the effect of decreasing the HWIN fraction, ln increasing the -available nitrogen and providing "quick release"
properties to the mixture. ~owever, it also adds suhstantially to the "burn" or phytotc~ic pctential of the mixture. It is important to note that urea is present in substantially all urea-formaldehyde fertilizer com~ositions from incomplete or equilibrium reactions during polymerization. Such unreacted urea has the same agronomic response and tolerance as commercially available urea which is deliberately added.
The manufacture of slow release urea-fcrmaldehyde reaction products for fertilizer applications requires ccnsiderable skill to prcduce the proper degree of polymerization required to achieve the desired fertilizer characteristic5~ Normally, they are prepared by first reacting urea and for~aldehyde at elevat~d temperatures in an alkaline solution to produce methylol ureas. The reaction mixture is then acidified which causes the methylcl ureas tc polymerize
2~ rapidly to form methylene urea polymers of varying chain lengt~
~Io M~ ~ertz 2/3 U S Patent 4,089,B99 to Greidinger et 21 discloses what i5 there described as a controlled reaction system for preparins slow release ureaform compounds with a low average ~egree of polymeriza-tion~ The Greidinger et al process involves the reaction of urea and formaldehyde in the presence of an acid catalyst for exten~ed reaction times ak lo~ temperatvres. While the patent discloses urea-formaldehyde compositions containing polymers having a sGmewh2t lower degree of pol~merization than conventional urea~orm :. ... _.. , ,. . .. _ .. . -- . ... . .
fertilizers, the compositions still cont2in large proportionS of lGnQer chaln polymërs.~ ~oreover, the Greidinger et al process is-incapable of producinq ccmpositions h2ving a significantly lower degree of pGlymeriz2~tion than those there shown.
U. S Patent 3,577,736 to ~ormaini discloses a multi-stage process for producing a li~id fertilizer suspension of ~reaform.
Bro2dly, the process involves the reaction of ure2 and formzldehyde in the.presence of ammoniz at an alkzline pH follcwed by acioifica-tion. The final product is stated to be ~ liquid fertilizer .. containing ureaform havin~ a relatively high activity inàex, that is, a relatively small amount of the hot wzter insGluble (~iWIN) fraction~
, SU1`1MARY OF THE INVENTION
.... _ _ . _ _ . .. ..
Ik is a primary object of the present invention to incre2se the agronomic efficiency ~f controlle~ rele2se solid nitrogen fer.ilizer products~ . .
~5 It is z;n addition21 object o~ thi5 invention to provide 2 controlled release solid nitro~en fe~til-zer which pos5esses the agronomic efficiency typic21 of sol~ble fertilizers svch as urea but which has m~ch greater s2fety.
, :
; '~
H.M. Goert2 2/3 It is a more specific object of this invent;on to provide a free flowing, particulate fertilizer cornposition prepared by the reaction of urea and formaldehyde which has ~ub6tantially increased proportions of the agronomically more efficient short chain methylene urea polymers.
The present invention is directed to a controlled release solid fertilizer composition in particulate form comprising the reaction product of urea and formaldehyde, the reaction product containing polymeric nitrogen in ~he form of meehylene urea polymers of varying chain leng~h. At least 60%
by weight of ~he polymeric nitrogén is in the form of cold water soluble ni~rogen polymers consisting of short chain polymers selected from the group consisting of methylene diurea and mixtures of methylene diurea and dimethylene ~riurea. The aforementioned compositions have been found to provide agronomic efficiency which is substantially greater than the most efficient controlled release solid fertilizer compostions presently known without substantial sacrifice of either safety or slow release. ~gronomic efficiency is herein defined as ~he ratio of nitrogen taken up by the plant to the total nitrogen applied, measured by the plant growtA response (color, fresh weights, etc.).
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a ternary diagram showing the water solllbility distribution of the various methylene urea polymers in the composition~ of the invention, FIGUR~ 2 is a ternary diagram showing the distribu~ion of the urea and forrnaldehyde reaction products and free urea in the composi~ions of ~he invention, and PIGUE~ES 3 ~ ~ are graphs showing ~he relative agronomic respon~e o~ short chain me~hylene urea polymers as compared to urea.
~, ", ~.~8~ H. ~. ~oertz-2/3 ~El'AIL~l:) T)F,SCRIPTIC)~
The invention has as its major emphasis the ~ater soluble short c~ain methylene urea polymer fraction of the fertilizer ccmposi~ions. ~pplicant has found that the short chain pclymers more closely resem~le urea in their efficiency of plant nutrient uptake but, unlike urea, are safe and not prone to environmental losses such as by leaching and volatilizatiGn. The accepted method c~ characterizing nitrogen-polymer distributicns has previously been based solely on CWIN and HWIN determinations, values whic~
characterize only the distributions of the longer methylene urea cha'ins. The present invention, on the other hand, deals with the - entire polymeric distribution including the methylene urea pGlymers contained in cold water soluble nitrogen (~ethylene diurea and dimethylene triurea), in hot water soluble nitrogen and in hot water insoluble nitrogen.
In the fertilizer compositions of the invention, at least 50%
of the polymeric nitrogen will cGme from short chain methylene ~iurea and dimethylene triurea polymers. The remainder Gf the methylene urea polymers will be the higher water insoluble polymers containing from four to six urea units including trimethylene tetraure~, tetramethylene pentaurea and pentamethylene hexaurea The average ~e~ree of polymeri~ation Gf the urea and fGrmaldehyde in the present compositions is always greater than 1.5. That is, the ratio of urea to methylene groups in the methylene urea polymers averages over 1 S. In addition to the methylene urea ~'~ polymers, the compositions will normally also contain nitrGgen frGm other sources, primarily from urea. The urea will usually be present in an amount ranging up to 70~ by weight and usually .~
, .
:~.
. .
, . .
: .
,, _7_ . .
mcre than 10%. T~e preferred ccmpositions of the inventlC~n cGntain hoth urea and methylene urea polymers, such t~at at least 45% ~f the nitrogen consists of cGld water sGluble reaction products when the amount of C~TIN is ~etween 15 and 35 percent of the nitrogen and :
mcre than 3~% Gf the nitrogen consists of ccld water soluble reaction products when the amount of CWIN is less than 15%. Even more preferably, less than 20~ by ~ei~ht conslsts of CWIN. (All values of C~IN and ~WIN referre~ to herein are determined in acccrdance with Of~icial ~ethods of ~nalysis of the Association of Official Analytical Che~ists, 13th Edition, 1980, Procedure 2.079).
' Fig. 1 is a ternary diagram shcwing t~e nitrogen water solubility distribution of ~ethylene urea polymers only - that is, ~old water soluble nitrogen pclymers tCWSNP), hot water solu~le nitrogen polymers ~WS~P) and ~ot water insGluble nitrogen polymers (~INP). Each of these ~ractions forms a vertex on the diagram.
This ternary diagram thus includes all possi~le proportions of methylene urea polymers of different degrees of polymerization.
Analytical techniques have not yet been developed which speci~ically identify all pGly~er chain lengths. ~owever h~h pressure liquid chromotography methods have rece~tly heen develcped ~y the present assignee to identify and quantify levels of methylene "
diurea (~DU) and dimet~ylene triurea (D~TU) in a water solution.
The remaining longer chain polymers are characterized thrGugh conventional solubility measurements in cold and hot water. ~D~, ~. ... .
: ~5 which has a degree of poly~erization (D.P.) of 2.0, is completely 5;~ soluble in cold water and therefore appears at the top vertex of the diagram. D~TU, ~hich has a D~P. of 1.5, i5 25% soluble in cold water, 75% solu~le in hot water and thus appears as a point along ~,.
the left edge of the diagram. Although the hisher methylene urea polymers have not heen isolated their solubilities can be interpolated from existing experimental evidence. Positions of ~he folIowing polymers are also plotted:
~TU tD.P. = 1.33) - Trimethylene tetraurea T~PU (D.P. c 1.25) - Tetramethylene pentaurea P~HU (D.P. = 1.20~7- Pentamethylene hexaurea ~;
~. ~
H~ oertz-~/3 P~U and hi~her pol~mers (~.P. < 1.~0) are assumed to he totally insolu~le in hot water~
Base~ on the assumption that solu~ilities o~ polymer mi~tures are linearly related to the proportions of the vario~s polymers ....
present, solu~illty re~ions can he ~efined hy average degree o~
polymerization. Thus, the lines A-A and B-B in ~igure 1 dQfine an average D.P. o~ l.S and 1.33, respectively. Polymer mixtures o~
- ,, . . - .- _ average ~.P. < 1.33 would occupy the solubility region below line ~
~-B. ~ixtures with average D.P. > 1.5 would occupy the solubility region above line A-A. ~ixtures with averaqe ~.P. between 1.33 an~ 1.5 occupy the space between the two lines.
In the present compositions, more than 50% of the polymeric nitrogen consists of short chain polymers~ This region is defined ~y the line A-C-E in Fig. 1. Point C is the midpoint of a line lS connectinq point A (100~ DMTU) and the ~WINP vertex (100~ long chain polymers)~ Point E is similarly the midpoint of a line connecting lnO% ~IJ ~nd the ~WINP vertex. All compositions below, or to the right, of lire A-C-E are thus excluded from the ~ccpe of the invention. In addition, the present compositions preferably ~0 contain less than ~0% of their polymeric nitrogen in water insoluble ~orm - or conversely over ~0~ of their polymeric ~itrogen in cold water soluble form. This region is defined by the line D~. The ~ertilizer compositions of the invention thus preferably contain polymeric nitro9en proportions falling in the region of the ~S ternary ~iagram to the left of line C-E and above the line D-D. In its even more preferred form, the ~ertilizer compositions of the invention contain over ~% of the polymeric nitrogen from cold water soluble polymers. This is shown by the region above line E-E. In its most preferred form, the compositions derive over ~0 of their polymeric nitro~en from cold water sol~ble polymers and these compositions are shown above the line F-F in Fig. 1. The percentage of polymeric nitrogen in cold water sol~ble ~orm is oertz-~3 determined by the weigh~ ratio o~ nitrogen ~rom .~DU and D~U to the total polymeric nitrogen content. The total polymeric nitrogen content is in turn the sum of C~IN, as analyzed by A~AC procedures, plus nitrogen from MDU and DMTU. Nitrogen from ~DU and DMTU are determined through Liquid Chromatography of the cold water soluble Craction .
Virtually all commercial urea-formaldehyde compositions contain varying proportions of urea nitrogen. In order therefore to illustrate and compare the present compositions with existing urea-formaldehyde fertilizer compositions, a second ternary diaqram has been prepared in which ~WSN ~nd HWIN (all cold water insol~ble nitrogen) have ~een ccmbined as one component, CWIN. CWSN is the second component and urea nitrogen is the third co~ponent (CWSN is cold water solu~le nitrogen excluding urea). In Fig. ?, the three vertices of the triangle are therefore CWSN, urea and CWIN. Since the focus of the present invention is the short chain polymers cvntained in the CWSN fraction, the ternary diagram of Fig. ~ is also use~ or illustrating the in-ention and its relatior. to the prior ~rt. As shown on this diagram, all known ureafor~
compositions are to the right of the ~O~ CWIN line labeled A-A
because, as above indicated, ureaform is defined as containing ~O%
or more C~IN. The aforementioned Greidinger-et al patent discloses a product containing "about 40% n cold water insoluble nitrogen.
The Greidinger et al compositions would therefore lay along a ~5 narrow band surrounding at least some portion of the line B-8 of the ternary diagram of Fig. 2. The bulk of presently available commercial urea-formaldehyde compositions are demarcated by the irregularly shaped region shown in Fig. 2. If the commercial U-F
fertilizers were to be mixed with varying amounts of urea, the 3n compositions would fall within the generally triangular area shown .
H~ ~ Goert~ 2~3 within dotted lines. The fertilizer COmpQsitiOnS of the pre-sent inven~îon fall above ~le line C-C in Fig. 2. The line C-C
defines the area of the dia~r~m containing mor-e than 45% ~SN
when the amount of CWIN is between 15 and 35 and more than 35%
S C~SN when the amount of CWIN is less than 15%.
The predominately low ~olymer methylene urea compositions -of the invention cannot ~e pxoduced by conventional urea-formal-dehyde condensation processes. The compositions are instead produced by a two-stage urea-formaldehyde condensation reaction involving the use of ammonia in the first stage. The process comprises prep2ring an aqueous mixture of urea, formaldehyde and ammonia, the molar ratio of urea to lormaldehyde ranging from 1 to 3, the molar ratio of ammonia to formaldehyde ranging from 0.05 to 1.00, heating ~he mixture to a temperature of from 140 to l90~F at an alkaline pH, the heating being stopped prior to ~he formation of a significant nu~ber of methylene urea polymers, the reaction produci.ng a mixture of methylol ureas and an unknown intermediate reaction product, acidifying the reaction mixture wit;n from 0.1-8% by weight of the mixture of an acid to initiate methylene urea polymerization and heating the reaction mixture to a tem~erature of from 180 D to 32~DF for a time suffi-cient to co~plete the methylene urea polymerizatio~ ~ d dry the reaction product, the majority of polymeric nitrogen present in said product consisting of short chain methylene urea polymers ~5 selected from the ~roup con.sistin~ of methylene diurea, dimethy-lene~triurlea and mixtures thereo.
~. M. Goertz 2/3 In the preferred practice of the process 9 the molar ratio o F urea to formaldehyde is from 1~2 to 205 ~nd the molar ratio of ammonia to formaldehyde is fr.om a.1 to OD 75. The mixture of urea, formaldehyde and ammonia i.s preferably heated to a temper~
-~ure of from 165~ t~ 185F and t~e water content of ,he reaction mixture is preEerably maintainecl at less than lS% by weight of ., :.: -.
the mixtureO The heating is contlnued only long enough to insure complete dissolution of urea and reaction of ammonia and to avoid formation of a signi~icant number of methylene Ulea polymers.
This time is ~ypically less than 45 mLnutes. To avoid formation of a substantial portion of long chain methylene urea polymers in the second phase of the reaction, the acid is added at rela-tively low levels, preferably from 0~5 tc 3% by weight o~ ~he mixture~
More specific~lly, the first stage of the process involves the reaction at aIl alkaline pH of urea and formaldehyde i~ ~he presence of ammonia to form the methylol ureas and an ammonia inte.rmediate. While the specific identity oE the ammonia inter-mediate is uncertain, it is believed critical to the formation ~0 of short chain methylene ureas, the production ~:E which is a cardinal object of the present process~ uid chromatographic studies indicate that the a~onia i~termediate is simllar in structure, but not identical, to hexamethylenetetramine, Dur-ing the second stage of the process, in which the reaction mix-ture is acidified to initiate methylene urea polym~rization~
the ammonia intermediate appears to tempex or control the rate of reaction resulting in a hi.gher proportion ~f short chain H. M, Goext~, 2/3 ~ 12 -pol~mers~ The process may be carried out in ei.ther a batch or continuous manner~
The first stag~ of the process may use unreacted urea ~nd unreactea formaldehyde or a urea and for~aidehyde source such as a commercially available aqueous urea form~ldehyde concen-trate~ One such concentrate is known as ~FC-85 and is a pre-condensed solution of formaldehyde and urea containing sub-stantial amounts of free for.~aldehyde and dimethylol ureas~ If a concentxate is used~ ~hen solid urea should also be added to -~he reaction mixt~re to bring the urea-formaldehyde molar ratio within t~e range of 1 to 3 (U/~), preferably 1.2 to 2.5. The urea may be in the form of prilled or granular urea or urea liquor solution. O~her sources of formaldehyde are gaseous formaldehyde and paraformaldehyde. The urea source and for~al-lS dehyde source are brought together in a heated tank and suffi-cient heat and watex are supplied to allow complete dissolution of the solid urea~ The amount of water should preferably be (imi~ed to less than 15% of the liquid mixtureO Higher amounts will a*fect the reacti~ity of the mixture and the ability to produce a dry granular product. Ammonia is then added to the urea-for.~aldehyde-water mixture. The source of ammonia is not critical; anhydrous is the least expensive. The amount of ammonia addition is, howeve~, critical to the final product since it forms the reaction intermediate which ultimately con-:25 trols the degree of polymerization. The mola.r ratio of ammonia to form,~ldehyde can be varied from 0.05 to lo 00 ~ the latter being a sr~all exoess over the stoichiometric limit of :~&~
H. M. Goert~. ~/3 - 13 ~
formaldehyde's capacity to react with ammonia= Normally~ the molar ratio of ammonia to formaldehyde will vary from ibout 0~10 to 0.75~ Am~onia addition can be simultaneous with the other components as lon~ as there i5 sufficient time to "trap" the ammo~ia in the reaction mixture solution. The presence of ammonia usually provides the alkaline ph necessaIy to avoid formation of substaIItial amounts of methylene ~reas. The entire phase one reaction is carried out lmder a single pH profile.
The temperature of the first stage o the reaction should be held between 140 and 190F (60 and 88~C)~ preferably be-tween 165 and 185~F (74 and 85C). The formation of the reactive intexmedia~e from a~monia and formaldehyde is strongly exothermic and aids in the d~ssolution of ~rea thus reducing the external heat loadO The solution should be maintained above the "salting out'l temperature of the uxea until a clear solution is obtained. Total heating time for the first stage of the reaction will va~y from 5 to 45 minutes, nermally 70 to 40 minutes. At this point, the reaction solution consists largely of methylol ureas and the ammonia intermediates - no ~0 significant methylene urea polymerization has occurred. The heating should be continued only sufficiently long to insure dis-solution of urea and formation of the unkno~m ammonia intermediate.
The compositions of the invention may be used either with or without an inert carrier. It is preferable to use a carrier in the practice of the invention because the absence of long chain polymers mcikes it more difficult to create the particle substrate necessary for a particulate product~ The composition ~. Mo Goertz 2/3 may also conkain phosphorus or potassium nutrients ~as P2Os or K20) and secondary or micronutrients to produce "complete"
fer~ilizers rather than ni~rogen only fertilizers. One par-~icularly sui~able carrier is expanded or porous vermicu~ite of the type shown, for exam~le, in ~.S. patent 3,076~700 to V. A~ Renner. If a porous carrier is used, the methylol ureas tog~ther with the unknown intermediate from ~he first stage of the reaction ar~ sprayed in liquid solution onto the carrier which typically will have been mixed with a source of phospho~us and po~assium nutrients such as mono-ammonium phosphate, potas-si~m slllfate or potassium chloride. In addition, other salts such as ammonium sulfate and ferrous sulfate may be added. The carrier should be used in an amount such that it will co~prise about 10 to 50% by weight, usually 20 to 35~ r of the total lS weight of the fertilizer composition. The carrier and fertilizer are then acidi~ied byl for example, spraying evenly with sulfuric or phosphoric acid to condense the reactive intel~ediates to fGrm methylene urea polymers. The now granular or particulate product containing fertili~er within the pores of the carrier ~0 :is then cured to effect final condensation and dried.
A number of inert absorbent carriers may be used. Expand-ed vermuculite is particularly useful because of its high ab~
sorptive capacity. The inert carrier may be used with or wi~h-out other fertilizer materials such as P2Os or K2O sources or ~5 secondary and minor ele~ents~ If it is desired to add nutrients other than nitrogen to the fertilizer, potassium and phosphate sources may be added such as potassium sulfat~, potassi~n
~Io M~ ~ertz 2/3 U S Patent 4,089,B99 to Greidinger et 21 discloses what i5 there described as a controlled reaction system for preparins slow release ureaform compounds with a low average ~egree of polymeriza-tion~ The Greidinger et al process involves the reaction of urea and formaldehyde in the presence of an acid catalyst for exten~ed reaction times ak lo~ temperatvres. While the patent discloses urea-formaldehyde compositions containing polymers having a sGmewh2t lower degree of pol~merization than conventional urea~orm :. ... _.. , ,. . .. _ .. . -- . ... . .
fertilizers, the compositions still cont2in large proportionS of lGnQer chaln polymërs.~ ~oreover, the Greidinger et al process is-incapable of producinq ccmpositions h2ving a significantly lower degree of pGlymeriz2~tion than those there shown.
U. S Patent 3,577,736 to ~ormaini discloses a multi-stage process for producing a li~id fertilizer suspension of ~reaform.
Bro2dly, the process involves the reaction of ure2 and formzldehyde in the.presence of ammoniz at an alkzline pH follcwed by acioifica-tion. The final product is stated to be ~ liquid fertilizer .. containing ureaform havin~ a relatively high activity inàex, that is, a relatively small amount of the hot wzter insGluble (~iWIN) fraction~
, SU1`1MARY OF THE INVENTION
.... _ _ . _ _ . .. ..
Ik is a primary object of the present invention to incre2se the agronomic efficiency ~f controlle~ rele2se solid nitrogen fer.ilizer products~ . .
~5 It is z;n addition21 object o~ thi5 invention to provide 2 controlled release solid nitro~en fe~til-zer which pos5esses the agronomic efficiency typic21 of sol~ble fertilizers svch as urea but which has m~ch greater s2fety.
, :
; '~
H.M. Goert2 2/3 It is a more specific object of this invent;on to provide a free flowing, particulate fertilizer cornposition prepared by the reaction of urea and formaldehyde which has ~ub6tantially increased proportions of the agronomically more efficient short chain methylene urea polymers.
The present invention is directed to a controlled release solid fertilizer composition in particulate form comprising the reaction product of urea and formaldehyde, the reaction product containing polymeric nitrogen in ~he form of meehylene urea polymers of varying chain leng~h. At least 60%
by weight of ~he polymeric nitrogén is in the form of cold water soluble ni~rogen polymers consisting of short chain polymers selected from the group consisting of methylene diurea and mixtures of methylene diurea and dimethylene ~riurea. The aforementioned compositions have been found to provide agronomic efficiency which is substantially greater than the most efficient controlled release solid fertilizer compostions presently known without substantial sacrifice of either safety or slow release. ~gronomic efficiency is herein defined as ~he ratio of nitrogen taken up by the plant to the total nitrogen applied, measured by the plant growtA response (color, fresh weights, etc.).
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a ternary diagram showing the water solllbility distribution of the various methylene urea polymers in the composition~ of the invention, FIGUR~ 2 is a ternary diagram showing the distribu~ion of the urea and forrnaldehyde reaction products and free urea in the composi~ions of ~he invention, and PIGUE~ES 3 ~ ~ are graphs showing ~he relative agronomic respon~e o~ short chain me~hylene urea polymers as compared to urea.
~, ", ~.~8~ H. ~. ~oertz-2/3 ~El'AIL~l:) T)F,SCRIPTIC)~
The invention has as its major emphasis the ~ater soluble short c~ain methylene urea polymer fraction of the fertilizer ccmposi~ions. ~pplicant has found that the short chain pclymers more closely resem~le urea in their efficiency of plant nutrient uptake but, unlike urea, are safe and not prone to environmental losses such as by leaching and volatilizatiGn. The accepted method c~ characterizing nitrogen-polymer distributicns has previously been based solely on CWIN and HWIN determinations, values whic~
characterize only the distributions of the longer methylene urea cha'ins. The present invention, on the other hand, deals with the - entire polymeric distribution including the methylene urea pGlymers contained in cold water soluble nitrogen (~ethylene diurea and dimethylene triurea), in hot water soluble nitrogen and in hot water insoluble nitrogen.
In the fertilizer compositions of the invention, at least 50%
of the polymeric nitrogen will cGme from short chain methylene ~iurea and dimethylene triurea polymers. The remainder Gf the methylene urea polymers will be the higher water insoluble polymers containing from four to six urea units including trimethylene tetraure~, tetramethylene pentaurea and pentamethylene hexaurea The average ~e~ree of polymeri~ation Gf the urea and fGrmaldehyde in the present compositions is always greater than 1.5. That is, the ratio of urea to methylene groups in the methylene urea polymers averages over 1 S. In addition to the methylene urea ~'~ polymers, the compositions will normally also contain nitrGgen frGm other sources, primarily from urea. The urea will usually be present in an amount ranging up to 70~ by weight and usually .~
, .
:~.
. .
, . .
: .
,, _7_ . .
mcre than 10%. T~e preferred ccmpositions of the inventlC~n cGntain hoth urea and methylene urea polymers, such t~at at least 45% ~f the nitrogen consists of cGld water sGluble reaction products when the amount of C~TIN is ~etween 15 and 35 percent of the nitrogen and :
mcre than 3~% Gf the nitrogen consists of ccld water soluble reaction products when the amount of CWIN is less than 15%. Even more preferably, less than 20~ by ~ei~ht conslsts of CWIN. (All values of C~IN and ~WIN referre~ to herein are determined in acccrdance with Of~icial ~ethods of ~nalysis of the Association of Official Analytical Che~ists, 13th Edition, 1980, Procedure 2.079).
' Fig. 1 is a ternary diagram shcwing t~e nitrogen water solubility distribution of ~ethylene urea polymers only - that is, ~old water soluble nitrogen pclymers tCWSNP), hot water solu~le nitrogen polymers ~WS~P) and ~ot water insGluble nitrogen polymers (~INP). Each of these ~ractions forms a vertex on the diagram.
This ternary diagram thus includes all possi~le proportions of methylene urea polymers of different degrees of polymerization.
Analytical techniques have not yet been developed which speci~ically identify all pGly~er chain lengths. ~owever h~h pressure liquid chromotography methods have rece~tly heen develcped ~y the present assignee to identify and quantify levels of methylene "
diurea (~DU) and dimet~ylene triurea (D~TU) in a water solution.
The remaining longer chain polymers are characterized thrGugh conventional solubility measurements in cold and hot water. ~D~, ~. ... .
: ~5 which has a degree of poly~erization (D.P.) of 2.0, is completely 5;~ soluble in cold water and therefore appears at the top vertex of the diagram. D~TU, ~hich has a D~P. of 1.5, i5 25% soluble in cold water, 75% solu~le in hot water and thus appears as a point along ~,.
the left edge of the diagram. Although the hisher methylene urea polymers have not heen isolated their solubilities can be interpolated from existing experimental evidence. Positions of ~he folIowing polymers are also plotted:
~TU tD.P. = 1.33) - Trimethylene tetraurea T~PU (D.P. c 1.25) - Tetramethylene pentaurea P~HU (D.P. = 1.20~7- Pentamethylene hexaurea ~;
~. ~
H~ oertz-~/3 P~U and hi~her pol~mers (~.P. < 1.~0) are assumed to he totally insolu~le in hot water~
Base~ on the assumption that solu~ilities o~ polymer mi~tures are linearly related to the proportions of the vario~s polymers ....
present, solu~illty re~ions can he ~efined hy average degree o~
polymerization. Thus, the lines A-A and B-B in ~igure 1 dQfine an average D.P. o~ l.S and 1.33, respectively. Polymer mixtures o~
- ,, . . - .- _ average ~.P. < 1.33 would occupy the solubility region below line ~
~-B. ~ixtures with average D.P. > 1.5 would occupy the solubility region above line A-A. ~ixtures with averaqe ~.P. between 1.33 an~ 1.5 occupy the space between the two lines.
In the present compositions, more than 50% of the polymeric nitrogen consists of short chain polymers~ This region is defined ~y the line A-C-E in Fig. 1. Point C is the midpoint of a line lS connectinq point A (100~ DMTU) and the ~WINP vertex (100~ long chain polymers)~ Point E is similarly the midpoint of a line connecting lnO% ~IJ ~nd the ~WINP vertex. All compositions below, or to the right, of lire A-C-E are thus excluded from the ~ccpe of the invention. In addition, the present compositions preferably ~0 contain less than ~0% of their polymeric nitrogen in water insoluble ~orm - or conversely over ~0~ of their polymeric ~itrogen in cold water soluble form. This region is defined by the line D~. The ~ertilizer compositions of the invention thus preferably contain polymeric nitro9en proportions falling in the region of the ~S ternary ~iagram to the left of line C-E and above the line D-D. In its even more preferred form, the ~ertilizer compositions of the invention contain over ~% of the polymeric nitrogen from cold water soluble polymers. This is shown by the region above line E-E. In its most preferred form, the compositions derive over ~0 of their polymeric nitro~en from cold water sol~ble polymers and these compositions are shown above the line F-F in Fig. 1. The percentage of polymeric nitrogen in cold water sol~ble ~orm is oertz-~3 determined by the weigh~ ratio o~ nitrogen ~rom .~DU and D~U to the total polymeric nitrogen content. The total polymeric nitrogen content is in turn the sum of C~IN, as analyzed by A~AC procedures, plus nitrogen from MDU and DMTU. Nitrogen from ~DU and DMTU are determined through Liquid Chromatography of the cold water soluble Craction .
Virtually all commercial urea-formaldehyde compositions contain varying proportions of urea nitrogen. In order therefore to illustrate and compare the present compositions with existing urea-formaldehyde fertilizer compositions, a second ternary diaqram has been prepared in which ~WSN ~nd HWIN (all cold water insol~ble nitrogen) have ~een ccmbined as one component, CWIN. CWSN is the second component and urea nitrogen is the third co~ponent (CWSN is cold water solu~le nitrogen excluding urea). In Fig. ?, the three vertices of the triangle are therefore CWSN, urea and CWIN. Since the focus of the present invention is the short chain polymers cvntained in the CWSN fraction, the ternary diagram of Fig. ~ is also use~ or illustrating the in-ention and its relatior. to the prior ~rt. As shown on this diagram, all known ureafor~
compositions are to the right of the ~O~ CWIN line labeled A-A
because, as above indicated, ureaform is defined as containing ~O%
or more C~IN. The aforementioned Greidinger-et al patent discloses a product containing "about 40% n cold water insoluble nitrogen.
The Greidinger et al compositions would therefore lay along a ~5 narrow band surrounding at least some portion of the line B-8 of the ternary diagram of Fig. 2. The bulk of presently available commercial urea-formaldehyde compositions are demarcated by the irregularly shaped region shown in Fig. 2. If the commercial U-F
fertilizers were to be mixed with varying amounts of urea, the 3n compositions would fall within the generally triangular area shown .
H~ ~ Goert~ 2~3 within dotted lines. The fertilizer COmpQsitiOnS of the pre-sent inven~îon fall above ~le line C-C in Fig. 2. The line C-C
defines the area of the dia~r~m containing mor-e than 45% ~SN
when the amount of CWIN is between 15 and 35 and more than 35%
S C~SN when the amount of CWIN is less than 15%.
The predominately low ~olymer methylene urea compositions -of the invention cannot ~e pxoduced by conventional urea-formal-dehyde condensation processes. The compositions are instead produced by a two-stage urea-formaldehyde condensation reaction involving the use of ammonia in the first stage. The process comprises prep2ring an aqueous mixture of urea, formaldehyde and ammonia, the molar ratio of urea to lormaldehyde ranging from 1 to 3, the molar ratio of ammonia to formaldehyde ranging from 0.05 to 1.00, heating ~he mixture to a temperature of from 140 to l90~F at an alkaline pH, the heating being stopped prior to ~he formation of a significant nu~ber of methylene urea polymers, the reaction produci.ng a mixture of methylol ureas and an unknown intermediate reaction product, acidifying the reaction mixture wit;n from 0.1-8% by weight of the mixture of an acid to initiate methylene urea polymerization and heating the reaction mixture to a tem~erature of from 180 D to 32~DF for a time suffi-cient to co~plete the methylene urea polymerizatio~ ~ d dry the reaction product, the majority of polymeric nitrogen present in said product consisting of short chain methylene urea polymers ~5 selected from the ~roup con.sistin~ of methylene diurea, dimethy-lene~triurlea and mixtures thereo.
~. M. Goertz 2/3 In the preferred practice of the process 9 the molar ratio o F urea to formaldehyde is from 1~2 to 205 ~nd the molar ratio of ammonia to formaldehyde is fr.om a.1 to OD 75. The mixture of urea, formaldehyde and ammonia i.s preferably heated to a temper~
-~ure of from 165~ t~ 185F and t~e water content of ,he reaction mixture is preEerably maintainecl at less than lS% by weight of ., :.: -.
the mixtureO The heating is contlnued only long enough to insure complete dissolution of urea and reaction of ammonia and to avoid formation of a signi~icant number of methylene Ulea polymers.
This time is ~ypically less than 45 mLnutes. To avoid formation of a substantial portion of long chain methylene urea polymers in the second phase of the reaction, the acid is added at rela-tively low levels, preferably from 0~5 tc 3% by weight o~ ~he mixture~
More specific~lly, the first stage of the process involves the reaction at aIl alkaline pH of urea and formaldehyde i~ ~he presence of ammonia to form the methylol ureas and an ammonia inte.rmediate. While the specific identity oE the ammonia inter-mediate is uncertain, it is believed critical to the formation ~0 of short chain methylene ureas, the production ~:E which is a cardinal object of the present process~ uid chromatographic studies indicate that the a~onia i~termediate is simllar in structure, but not identical, to hexamethylenetetramine, Dur-ing the second stage of the process, in which the reaction mix-ture is acidified to initiate methylene urea polym~rization~
the ammonia intermediate appears to tempex or control the rate of reaction resulting in a hi.gher proportion ~f short chain H. M, Goext~, 2/3 ~ 12 -pol~mers~ The process may be carried out in ei.ther a batch or continuous manner~
The first stag~ of the process may use unreacted urea ~nd unreactea formaldehyde or a urea and for~aidehyde source such as a commercially available aqueous urea form~ldehyde concen-trate~ One such concentrate is known as ~FC-85 and is a pre-condensed solution of formaldehyde and urea containing sub-stantial amounts of free for.~aldehyde and dimethylol ureas~ If a concentxate is used~ ~hen solid urea should also be added to -~he reaction mixt~re to bring the urea-formaldehyde molar ratio within t~e range of 1 to 3 (U/~), preferably 1.2 to 2.5. The urea may be in the form of prilled or granular urea or urea liquor solution. O~her sources of formaldehyde are gaseous formaldehyde and paraformaldehyde. The urea source and for~al-lS dehyde source are brought together in a heated tank and suffi-cient heat and watex are supplied to allow complete dissolution of the solid urea~ The amount of water should preferably be (imi~ed to less than 15% of the liquid mixtureO Higher amounts will a*fect the reacti~ity of the mixture and the ability to produce a dry granular product. Ammonia is then added to the urea-for.~aldehyde-water mixture. The source of ammonia is not critical; anhydrous is the least expensive. The amount of ammonia addition is, howeve~, critical to the final product since it forms the reaction intermediate which ultimately con-:25 trols the degree of polymerization. The mola.r ratio of ammonia to form,~ldehyde can be varied from 0.05 to lo 00 ~ the latter being a sr~all exoess over the stoichiometric limit of :~&~
H. M. Goert~. ~/3 - 13 ~
formaldehyde's capacity to react with ammonia= Normally~ the molar ratio of ammonia to formaldehyde will vary from ibout 0~10 to 0.75~ Am~onia addition can be simultaneous with the other components as lon~ as there i5 sufficient time to "trap" the ammo~ia in the reaction mixture solution. The presence of ammonia usually provides the alkaline ph necessaIy to avoid formation of substaIItial amounts of methylene ~reas. The entire phase one reaction is carried out lmder a single pH profile.
The temperature of the first stage o the reaction should be held between 140 and 190F (60 and 88~C)~ preferably be-tween 165 and 185~F (74 and 85C). The formation of the reactive intexmedia~e from a~monia and formaldehyde is strongly exothermic and aids in the d~ssolution of ~rea thus reducing the external heat loadO The solution should be maintained above the "salting out'l temperature of the uxea until a clear solution is obtained. Total heating time for the first stage of the reaction will va~y from 5 to 45 minutes, nermally 70 to 40 minutes. At this point, the reaction solution consists largely of methylol ureas and the ammonia intermediates - no ~0 significant methylene urea polymerization has occurred. The heating should be continued only sufficiently long to insure dis-solution of urea and formation of the unkno~m ammonia intermediate.
The compositions of the invention may be used either with or without an inert carrier. It is preferable to use a carrier in the practice of the invention because the absence of long chain polymers mcikes it more difficult to create the particle substrate necessary for a particulate product~ The composition ~. Mo Goertz 2/3 may also conkain phosphorus or potassium nutrients ~as P2Os or K20) and secondary or micronutrients to produce "complete"
fer~ilizers rather than ni~rogen only fertilizers. One par-~icularly sui~able carrier is expanded or porous vermicu~ite of the type shown, for exam~le, in ~.S. patent 3,076~700 to V. A~ Renner. If a porous carrier is used, the methylol ureas tog~ther with the unknown intermediate from ~he first stage of the reaction ar~ sprayed in liquid solution onto the carrier which typically will have been mixed with a source of phospho~us and po~assium nutrients such as mono-ammonium phosphate, potas-si~m slllfate or potassium chloride. In addition, other salts such as ammonium sulfate and ferrous sulfate may be added. The carrier should be used in an amount such that it will co~prise about 10 to 50% by weight, usually 20 to 35~ r of the total lS weight of the fertilizer composition. The carrier and fertilizer are then acidi~ied byl for example, spraying evenly with sulfuric or phosphoric acid to condense the reactive intel~ediates to fGrm methylene urea polymers. The now granular or particulate product containing fertili~er within the pores of the carrier ~0 :is then cured to effect final condensation and dried.
A number of inert absorbent carriers may be used. Expand-ed vermuculite is particularly useful because of its high ab~
sorptive capacity. The inert carrier may be used with or wi~h-out other fertilizer materials such as P2Os or K2O sources or ~5 secondary and minor ele~ents~ If it is desired to add nutrients other than nitrogen to the fertilizer, potassium and phosphate sources may be added such as potassium sulfat~, potassi~n
3~L~
H~ M~ Goert.z ~/3 chloride, potassium phosphate~ potassium nitrate and mono-a~monium phosphate~ Typically, f.-rom 0 to 60 parts ~y'weight of potassium calculatea as ~2 and 0 to 60 parts of phosphorus calcul2ted as P2O5 per 1000 parts by ~7eight of the urea and fo,~maldehyde reaction mixture may be added~ Other secondary fertil.izer elements or micronutrients may also be added at this ., .
poi~ " if Aesired, such as sources of iron, m~lganese, boron, molybelenum, ~nagnesium, copper, zinc, iodine, calci-~ and sulfur~
The elements may be added in elemental form or as their salts 1~ 01 chelatesO
As shown in the aforementioned U.S. patent 3,076,700~ ~he acid source is sprayed onto the mixture to initi2te the methy'.--lene urea polymerization reaction. The amount of acid used is critical to the degree of pol~merization and should range from 0.1 to 8% by weight of the reaction mixture~ preferably .5 to 3~ by weight. When a carrier is used, the acid addition shoul~
be kept below 4% to avoid the formation of higher methylene urea pol~ers. ~igher levels of acid would result in substantial for-mation of longer chain me~ylene ureas. No external heat is ~0 necessary at this po~nt. Typically~ ~le acid will be sulfuric acid, although other acids such as phosphoric acid may be used~
Once ~he condensation reaction has been initiated, the wet mi~ture is trans~erreA to a dryer reactor where the condensat:ion proceeds ~Jhile the product is simultaneously dried to a flowable state. No inal p~ ad~ustment or neutralization is necessary.
'I'he dr~ing ti~e has also been found to be critical to the deg:ree of urea polymerization. ~he preferred r~lge o~ drying ~. M~ ~oert% 2~3 temperature is between 220 to 320F (104~ to 160~C~ with typi-cal residence times varying from ~5 to 35 minutes. The time-te~perature relationships a.re, of course, a function of ~le quant.ity of material being dxiedl the desired final moisture content and the desired degree of urea polymerization~ A nu~ber of co~n~rcial driers are suitable for this purpose i~cluding _ . . .
continuous belt, tray, ~turbo-driers", rotary~ etc~ As the material is dried, especially at elevated temperatures, arnrnonia may be drawn off in the stack gas. This may be recycled to ~he solution phase of the process thus providing for a closed systemc Once dried, the fertilizer material i5 sized and may be used as a finished productO It can also be used as a substrate for va~ious active ingredien~s including herbicides, fungicides and insecticides or additional plant nutrients, or it can be lS used as a feedstock for processes designed for altering physical properties as described in r~ prior V.S. patent 4,025,329.
Alternatively~ the fertilizer compositions may themselves be used without a carrier. A method for producing such urea-formaldehyde fertilizers is disclosed in U.S~ patent 3,70S,794 to Ra H~ Czurak et al. Fertilizer compositions ~ithout a carrier in accordance with the present invention are prepared essentially as set forth in the preceeding paragraph except that, rather than sprayirlg the methylol urea-intermediate liq~id suspens.ion onto a carrier, t~e acid is injected into the liquid ~5 suspension to initiate the stage 2 condensation reaction. The reaction r~ixture, now in liquid or semi-solid fonn, is then transferred to a dryer to remove water and complete condensationJ
if rlecessar~, to fo~n a dry, granular fertilizera Drying and 3~
E~ M~ ~oert~ ?~/3 comple-ticn of condensation is carxied out in accordance with the process disclosed in the aforesaid U.S. patent 3~705r794~ As ~here sho~n, the acidified ~ixture is spread into a layer t~pi~
cally having an initial thickness in the range of one to si~
S inches, This may ~e done as the methylene urea reaction is initiated by quickly discharging ~he fluid stream onto a curing . .
conveyor upon which the reaction mlxture coalesces into a semi-~ '' solidO Curing will typically be continued on t:he conveyor at a temperature in the range of 180 to 220~F fox a period of at 12ast one minute to produce a physically stable material which can ~e easily handled, ~he still wet mixture is transferred to a dryer reactor where the condensation proceeds while ~he product is simultaneously dried to a 10wa'ole stateO l~le tem-perature of drying has also been shown to be critical to the desree of urea polymerization when a carrier is not used. T~e preferred range of drying temperature is between 2~0~ to 320F
('~4 to 16~^C) w'th typical dr~ing times ~arying from 15 ~o 35 minutes. A nu~ber of commercial driers are ayai~ suitable for '' this purpose as is the case when a carrier is used~
A third form of particulate fertilizer may ~e made by slurry-ing an inert carrier wlth the resin (methylol urea and inter~
mediate) before acidifying. The inert carrier may~ for exam~le, be sawdust, gypsllm~ coffee grounds, clays or other well }cnown inert carriers in particulate form. The type and amount o ~5 inert substance :is limited only by the viscosity or thickn~ss o:E the slurry and i ts effect on reactivity of -~he resin. After ~cidifying~ the condensation reaction proceeds in and around ~ 3 ~o Mo ~oe.rt~ 2~3 ~le inert particles which serve as granular nucle~ he~hex used with or without a carrier, the comDositions ~ill normally contai.n from 20 to 41% by weight of nitrogen.
The following exam~les are illustrative of ~he practlce of ~he invention. All parts and percentages are ~y weight un-less o~herwise indicated.
. .
Urea, urea-formaldehyde concentrate (UFC-~5), anhydrous ammonia and water were fed into an agitated tank at 5.75, 2.26, 0.51 and 0.56 lbs/min respectively. ~UFC-85 is a precondensed solution of formaldehyde and UreA containing substc~ntial amo~nts of free formaldehyde and dimethylol ureas.) Ihe xesidence time in the tank was approximately 45 minutes during which time the solution was maintained at 180F and a p~ of 10.1. The solution was then sprayed into a continuous muxer being fed with expanded vermiculite, fine]y ground mono-~mmollium phosphate and finely ground potassi~m chloride at .rates of 2.75, 0.72 and 0.64 lbs/mu~
respectivelyO Sul~uric acid (50~ concentration) was sprayed on~
to the I~xture at 0.67 lb/mun to initiate the condensation reac-~on~ The reaction mlxture was passed through a continuous belt dryer for 20 minutes at 300~. The resulting solid at ab~ut 2.0 percent mois~ure was crushed and screened to pass an 8-mesh screen tUS sieves~. The product had the nutrient characteristics shown in Table I.
&~ D~ . fiO e~t~ 2/3 --lg ~
a~les ~ 4 These examples show h~w the nitrGgen polymer ~istributicn can be al~er d through proper choice of ope~ating condit.ions, The process sequence is essentially the same as ~xample 1.
~1GW Rate (~/min Material xample 2 ~xample 3 ~xample _ _ .
Urea 4.~6 ~.49 5.49 UFC .. ~--. 3.89 2.~5 3~59 ammonia~ 0.72 0.41 - - -- .~1 1~ water . 0.48 0.~1 .58 ex~anded vermiculite 2.89 2.83 3.08 ~ona~monium Phosph2te 0.S8 0.69 .~9 Potassium ~hloride 0.~2 0.~4 o65 Sulfuric ~cid (50%~ 0.~9 0.4~ .a2 l~ ' Solution Temperature (F) 1~8F 1~9F 171GF
~ryer Tem~erature (F~ 300Gr . '2~0F3~0CF
This procedure yielded products with the characteristics shown in Table I.
xa~plas ~-7 ~n '~hese examples illustrate the man~fac-ture cr products without a carrier.
Resin (methylcl ureas and ammcnia interrnediate) preparation for eac~ of ~he products was identical and as fcllows:
a. I~rea~ UFC and ~4~H were added to a ~eaker. ~eating ~
the resin hegan immediately. The urea usually dissolved ccmpletely in less than 8 min.
b. 'rhe resin w~s brought to 170CF and ~eld at that temperature until 30 minutes of total heating (from start) was realized.
8() c. The resin pH was generally maintained between 9 and ll without addition of alk~li during the heating cycle.
d. The resin was acidulated using 50~ cGncentration acid~ at the 30 minute mark.
~19--H. ~. ';oert~-2/3 -2 ~
~ormulat.on variables were as follows:
(Urea/UFC) (N~40H/UFC) Acid (~ Total Ex~le ~ ht Weiqht Resin Wei~ht?
S 2.~ 0.12 3.0 l.9 0.~0 8.0 7 l.9 0.40 l~.0 e. After reaction, the samples were placed in pans in a thin layer for drying. The products were dried at 150F at - 40-50~ relativë humidity in a constant temperature-humidity chamber for 48-72 hours~ The materials were granulated (crushed) and had the product characteristics shown in Table I. Examples 5 and 7 were considered dry, qranular solids while Example 5 was considered a gummy solid.
l~ Tables II and III show the agronomic performance of the materials of xamples l through 4. Table II shows the relative response and tolerance characteristics of Exa~ples 1-4 compared to eq~al rates of nitrogen as ~rea, a commercially available controlled release nitrogen fertilizer sold under the Tur~ 3uilder tradcrnark and an unfertilized check. It is readily seen that the materials which are rich in short chained rnethylene ureas have desirable response characteristics (both initial and residual response) as well as improved safety over urea.
Table III illustrates the impr~ved nitrogen efficiency of short ~5 chained methylene ~rea products. Products of Examples l-~ were applied at reduced nitrogen rates compared to an accepted col~trolled release material which was applied at 0.9# N/~. In spite of rate reductions of 17% - 22~, the products gave initial and residual response characteristics ~avorable to the standard even though it was applied at a hîgher rateO Results were confirmed on several soil types.
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t ~ .Gert~-~/3 The 'oregoing Tables II and III show ~hat nitrogen efficiency was drama~ically increased ~y utilizing urea fGrmaldehyde reaction prcducts containing the critical ~igh levels Gf ~U and ~TU. This transla~es-into reduced rates of applic~tion necessary for 5 equivalent performance or equivalent rates to cbtain superiGr performance as compared to currently availahle slow release nitrogen sources.
.. . . . . ... .. ..
The invention is based in part on the discovery that the short chain ~U and D~TU pclymers have cGnsiderably greater agronornic efficiency than the hisher methylene urea polymers but yet retain the safety and slow release characteristics of the higher pol~ners. Theoretically, it would be desirable, if econornically ~easible, to produce a fertilizer containing only the short chain polymers. The ~ollGwing example is intended tG illustrate ,his conclusion.
Exa~ple ~ -This example shows the nitrcG;en efficiency, agroncrnic safety and slcw release characteristics cf shcrt chained methylene ureas in their pure state.
~0 Chemically, pure met~ylene diurea (~V) and dimet~ylene triurea (~TU~ were prepared using preparative liquid chrGmatography.
concentrated aqueous solution of a mixture of methylene ureas was injected onto a liquid chrcmatography cGlumn with water as the ~obil phase ~200-500 ml/min). Individua~ ~ethylene ureas were ~2r~ collected after detectlon by refractive index. Water was removed by evaporation from fractions collected and purity determined by analytical high pressure liquid chrcmatography, molecular weight ~eterrninations and elemental analysisO
H. ~o GGer~,z--2/3 -~5-These ~GrmulatiGns were applied ~o ~entucky bluegrass at a ra~e o 5 lbs N/100~ S~. ~t. Fig. ~ shows the fresh weight cf lue~rass clippings as affected by urea and the methylen2 urea poly~ers. ~s shcwn in Fi~. 3, urea, methy'lene diurea and ~, dimethylene triurea induced ccmparable growth during the ~irst 28 days of ~he stu~y~ ~owever, on the 35th day, ~he residual charac~eristics of the'~DU and D~TU as ccmpared to urea became appare~ and continued un~il the 5~th day. T~ese di~ferences were statistically significant at the 5% level during mGst of this time 1~ span.
' In Fig. ~, clipping fresh weights were ccmpared using average yield over three week time spans. Pooling the data, irrespective c~ rates (~, 5, 8 lh. ~1000 sq. ft), reduced the variability which ~ay cccur because of environmental stress and pr~vided a mGre 1~ accurate picture of the results. Fig. 4 shows the residual charac~eristics of ~U and ~TU over a 27 week time frame~ DMTU
w25 significantly better than urea at all dates except during the Eirst three weeks. ~DU was similar to urea ~uring the ~irst sl~
~eeks, then was significantiy better than urea during the remainder of the test. ~DU & D~TU both exhibit residual characteristics sigrlificantly superior to urea.
Tahle IV illustrates the safety of short chain methylene urea polymers. 'Jrea, ~DU, D~TU and dimethylGlurea were applied to moist Kentucky Bluegrass at 8 lh N/1000 ft . 3imethylolurea is ~5 one of the reaction intermediates in the methylene urea polymeri~ation. Neither ~DU nor D~TU produced any noticeable injury whereas urea and dimethylolurea gave ccnsiderable injury.
--~S--~ l.M. Go~rtz 2~
-26~ 3~
Table IV
Tolerance of Kentucky Bluegra~s to Urea, Methylene Vraas dlmethylolurea ~ Injury Nitrogen Lbs N/lOOO Days ~f~er Treating Source S~. Ft. 3 7 21 2~
_ __ _ _ _ __ Methylene diurea 8 0 1.7 0 Dimethylene triurea 8 0 0 0 0 Urea B 26.725~0 23.0 14.0 dime-thylolurea 8 30.065.0 5~.0 57.0 Control O O O O O
The inventlon has been illustrated wi~h specific examples of fertilizer compositions. Many o~her nutrients, a~
well as micro-nutrients, and control chemicals ~uch as herbicides, fungicides and insecticides may be combined wi~h ~he products of the invention. Examples of other additives are shown in the aforementioned R~nner U~S. pa-ten~ 3,076,700 and Czurak et al U.S. patent 3,705,794. Other pesticides which may be used are shown in the Pesticide Manual, 6~h Edi~ion~ British Crop Protection Council, 1980. Other herbicides which may be used are shown in Weed Control, 2nd Edition, 1962, Robbins e~
al., McGraw-Hill Book Company, Inc., New York, Ne~ York. Other fer-tilizer nu~rients which may be used in combination are shown in Commercial Fertilizers, 5th Edition, 1955, Collings, McGraw-Hill Book Inc., New York, New York.
H~ M~ Goert.z ~/3 chloride, potassium phosphate~ potassium nitrate and mono-a~monium phosphate~ Typically, f.-rom 0 to 60 parts ~y'weight of potassium calculatea as ~2 and 0 to 60 parts of phosphorus calcul2ted as P2O5 per 1000 parts by ~7eight of the urea and fo,~maldehyde reaction mixture may be added~ Other secondary fertil.izer elements or micronutrients may also be added at this ., .
poi~ " if Aesired, such as sources of iron, m~lganese, boron, molybelenum, ~nagnesium, copper, zinc, iodine, calci-~ and sulfur~
The elements may be added in elemental form or as their salts 1~ 01 chelatesO
As shown in the aforementioned U.S. patent 3,076,700~ ~he acid source is sprayed onto the mixture to initi2te the methy'.--lene urea polymerization reaction. The amount of acid used is critical to the degree of pol~merization and should range from 0.1 to 8% by weight of the reaction mixture~ preferably .5 to 3~ by weight. When a carrier is used, the acid addition shoul~
be kept below 4% to avoid the formation of higher methylene urea pol~ers. ~igher levels of acid would result in substantial for-mation of longer chain me~ylene ureas. No external heat is ~0 necessary at this po~nt. Typically~ ~le acid will be sulfuric acid, although other acids such as phosphoric acid may be used~
Once ~he condensation reaction has been initiated, the wet mi~ture is trans~erreA to a dryer reactor where the condensat:ion proceeds ~Jhile the product is simultaneously dried to a flowable state. No inal p~ ad~ustment or neutralization is necessary.
'I'he dr~ing ti~e has also been found to be critical to the deg:ree of urea polymerization. ~he preferred r~lge o~ drying ~. M~ ~oert% 2~3 temperature is between 220 to 320F (104~ to 160~C~ with typi-cal residence times varying from ~5 to 35 minutes. The time-te~perature relationships a.re, of course, a function of ~le quant.ity of material being dxiedl the desired final moisture content and the desired degree of urea polymerization~ A nu~ber of co~n~rcial driers are suitable for this purpose i~cluding _ . . .
continuous belt, tray, ~turbo-driers", rotary~ etc~ As the material is dried, especially at elevated temperatures, arnrnonia may be drawn off in the stack gas. This may be recycled to ~he solution phase of the process thus providing for a closed systemc Once dried, the fertilizer material i5 sized and may be used as a finished productO It can also be used as a substrate for va~ious active ingredien~s including herbicides, fungicides and insecticides or additional plant nutrients, or it can be lS used as a feedstock for processes designed for altering physical properties as described in r~ prior V.S. patent 4,025,329.
Alternatively~ the fertilizer compositions may themselves be used without a carrier. A method for producing such urea-formaldehyde fertilizers is disclosed in U.S~ patent 3,70S,794 to Ra H~ Czurak et al. Fertilizer compositions ~ithout a carrier in accordance with the present invention are prepared essentially as set forth in the preceeding paragraph except that, rather than sprayirlg the methylol urea-intermediate liq~id suspens.ion onto a carrier, t~e acid is injected into the liquid ~5 suspension to initiate the stage 2 condensation reaction. The reaction r~ixture, now in liquid or semi-solid fonn, is then transferred to a dryer to remove water and complete condensationJ
if rlecessar~, to fo~n a dry, granular fertilizera Drying and 3~
E~ M~ ~oert~ ?~/3 comple-ticn of condensation is carxied out in accordance with the process disclosed in the aforesaid U.S. patent 3~705r794~ As ~here sho~n, the acidified ~ixture is spread into a layer t~pi~
cally having an initial thickness in the range of one to si~
S inches, This may ~e done as the methylene urea reaction is initiated by quickly discharging ~he fluid stream onto a curing . .
conveyor upon which the reaction mlxture coalesces into a semi-~ '' solidO Curing will typically be continued on t:he conveyor at a temperature in the range of 180 to 220~F fox a period of at 12ast one minute to produce a physically stable material which can ~e easily handled, ~he still wet mixture is transferred to a dryer reactor where the condensation proceeds while ~he product is simultaneously dried to a 10wa'ole stateO l~le tem-perature of drying has also been shown to be critical to the desree of urea polymerization when a carrier is not used. T~e preferred range of drying temperature is between 2~0~ to 320F
('~4 to 16~^C) w'th typical dr~ing times ~arying from 15 ~o 35 minutes. A nu~ber of commercial driers are ayai~ suitable for '' this purpose as is the case when a carrier is used~
A third form of particulate fertilizer may ~e made by slurry-ing an inert carrier wlth the resin (methylol urea and inter~
mediate) before acidifying. The inert carrier may~ for exam~le, be sawdust, gypsllm~ coffee grounds, clays or other well }cnown inert carriers in particulate form. The type and amount o ~5 inert substance :is limited only by the viscosity or thickn~ss o:E the slurry and i ts effect on reactivity of -~he resin. After ~cidifying~ the condensation reaction proceeds in and around ~ 3 ~o Mo ~oe.rt~ 2~3 ~le inert particles which serve as granular nucle~ he~hex used with or without a carrier, the comDositions ~ill normally contai.n from 20 to 41% by weight of nitrogen.
The following exam~les are illustrative of ~he practlce of ~he invention. All parts and percentages are ~y weight un-less o~herwise indicated.
. .
Urea, urea-formaldehyde concentrate (UFC-~5), anhydrous ammonia and water were fed into an agitated tank at 5.75, 2.26, 0.51 and 0.56 lbs/min respectively. ~UFC-85 is a precondensed solution of formaldehyde and UreA containing substc~ntial amo~nts of free formaldehyde and dimethylol ureas.) Ihe xesidence time in the tank was approximately 45 minutes during which time the solution was maintained at 180F and a p~ of 10.1. The solution was then sprayed into a continuous muxer being fed with expanded vermiculite, fine]y ground mono-~mmollium phosphate and finely ground potassi~m chloride at .rates of 2.75, 0.72 and 0.64 lbs/mu~
respectivelyO Sul~uric acid (50~ concentration) was sprayed on~
to the I~xture at 0.67 lb/mun to initiate the condensation reac-~on~ The reaction mlxture was passed through a continuous belt dryer for 20 minutes at 300~. The resulting solid at ab~ut 2.0 percent mois~ure was crushed and screened to pass an 8-mesh screen tUS sieves~. The product had the nutrient characteristics shown in Table I.
&~ D~ . fiO e~t~ 2/3 --lg ~
a~les ~ 4 These examples show h~w the nitrGgen polymer ~istributicn can be al~er d through proper choice of ope~ating condit.ions, The process sequence is essentially the same as ~xample 1.
~1GW Rate (~/min Material xample 2 ~xample 3 ~xample _ _ .
Urea 4.~6 ~.49 5.49 UFC .. ~--. 3.89 2.~5 3~59 ammonia~ 0.72 0.41 - - -- .~1 1~ water . 0.48 0.~1 .58 ex~anded vermiculite 2.89 2.83 3.08 ~ona~monium Phosph2te 0.S8 0.69 .~9 Potassium ~hloride 0.~2 0.~4 o65 Sulfuric ~cid (50%~ 0.~9 0.4~ .a2 l~ ' Solution Temperature (F) 1~8F 1~9F 171GF
~ryer Tem~erature (F~ 300Gr . '2~0F3~0CF
This procedure yielded products with the characteristics shown in Table I.
xa~plas ~-7 ~n '~hese examples illustrate the man~fac-ture cr products without a carrier.
Resin (methylcl ureas and ammcnia interrnediate) preparation for eac~ of ~he products was identical and as fcllows:
a. I~rea~ UFC and ~4~H were added to a ~eaker. ~eating ~
the resin hegan immediately. The urea usually dissolved ccmpletely in less than 8 min.
b. 'rhe resin w~s brought to 170CF and ~eld at that temperature until 30 minutes of total heating (from start) was realized.
8() c. The resin pH was generally maintained between 9 and ll without addition of alk~li during the heating cycle.
d. The resin was acidulated using 50~ cGncentration acid~ at the 30 minute mark.
~19--H. ~. ';oert~-2/3 -2 ~
~ormulat.on variables were as follows:
(Urea/UFC) (N~40H/UFC) Acid (~ Total Ex~le ~ ht Weiqht Resin Wei~ht?
S 2.~ 0.12 3.0 l.9 0.~0 8.0 7 l.9 0.40 l~.0 e. After reaction, the samples were placed in pans in a thin layer for drying. The products were dried at 150F at - 40-50~ relativë humidity in a constant temperature-humidity chamber for 48-72 hours~ The materials were granulated (crushed) and had the product characteristics shown in Table I. Examples 5 and 7 were considered dry, qranular solids while Example 5 was considered a gummy solid.
l~ Tables II and III show the agronomic performance of the materials of xamples l through 4. Table II shows the relative response and tolerance characteristics of Exa~ples 1-4 compared to eq~al rates of nitrogen as ~rea, a commercially available controlled release nitrogen fertilizer sold under the Tur~ 3uilder tradcrnark and an unfertilized check. It is readily seen that the materials which are rich in short chained rnethylene ureas have desirable response characteristics (both initial and residual response) as well as improved safety over urea.
Table III illustrates the impr~ved nitrogen efficiency of short ~5 chained methylene ~rea products. Products of Examples l-~ were applied at reduced nitrogen rates compared to an accepted col~trolled release material which was applied at 0.9# N/~. In spite of rate reductions of 17% - 22~, the products gave initial and residual response characteristics ~avorable to the standard even though it was applied at a hîgher rateO Results were confirmed on several soil types.
H. M. Goertz-2/3 _ z _ r ~ o ( ~ o r . - D ~ _I c _ r ~c Z ~,~, . t~7 ~r ~ ~ O G. .. _ .
U F3 r~ ~9 r ~ ~ ~ ~D
o o .
:L .~ z r ~ ~ o~ r ~ r-k3 t,~ ~ ~ ~ ~ ~ ~
~;~ O o ~ o ~r~
Z r~ ~ c ~; C ~: r~
~ o ~ ~- o c c c~
~ dP 1~ ~ ~, ~r o c G
'Z r~ r~ t~) ~ C~ O O
Z 0 ~ O~ U') L~ . C~
~r u~ U~ u~ O CO ~:D
t~` ~ ~ r~ r~
X ~ ~ r^ ~r u~ ~ r--3 11. M. Goer~
v~ E ~ ~ ~
C :- ~ r7 C~ . . ~ . I . .
O --O ~;r r r r r- r-t~- xu~ ,~
r~
~:,. ~
G ._~ _ ___. __ _ ____ _ .
r~ L~ O ~
~_ ~ IJ
m c o ~ ~ ~ o o _ O~ r~1 ~ .... I ..
rn t) _ ~~ r r~ r- r ~
_____ Q ___. ______ _~__ a~ E
r~ O x u~ J ~ r ~ o V-- rn ~ ~ v a~ c~ r~
r aS:i~A ~ rJ~- __ _________.___ ~ ~ o-- ~ , ~ m c ~ r ~ cr O
r~ o - ~5 ~ r~ . . O . I . .
L. C~ C _C'~ CO a:) r~ r- ~ .
r~ ~ In Z
_ __ ___ ___________ o .~1 3 ~ ~ 3 E C
a ~ o~ I ,~ O r~
r rf5 Q, L -_t ~.q Cl~ ~ ~J ~ C' O U^~ C' O ~-0 JJ . O
r~
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IJ V ~J a~ . ~u a)uJ ¢ 4_~ ~ o CL C~ D C:) ~ ,~ r~ c ~
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~Z ~ ~ ~ ~ ~ ,~ ~
V~ -- ~5 ~ CL ~ :L ~ y E
u~ ~ v ~ ~ E E E E E r~ ~ r~ ::
r3 ~ u) to ~ r~ ~S rr) ~ rr~ r~ Z
~- oa) ~ x ~ x x ~ ~ 3 c V rr, E- ~ ~ r~ r~ r~ r~ ~, ~ o ~:1. M. Goertz~2/3 --2 3 ~
E~ dO c ~ o r ~ ~ .
U~ tO ~ N i` r~ . . o o . . :LI
O ~-1 U) O ~ ~1 C C:~ OC~ C~
t Ar~:! ____ _--____ ___ ____._ _ O
_ o~ J ~ ~ c~ ~I G
_____ t` ~ r t- t p~C~) ~::0 O
m ~: ~ ~ 3 ~~ ~ c o ,e ~ r r ~ r o~ G ~ ~
t~ m ~ a~ ~~ ~ ~ c ~:; c t~ ~ -------- ---------- r r r r r ~ ~ ~
o ~ ~ tc tn _ o ~ ~ ~ ~ ~
coo . ~c a)~J . -~n ~ Q) ~ ~ m C ~ ~ ~:! ~ ~ ~ L~ ~
VJ ~ ,_~ ~ o r tn ~ ~ t~ ~ ~ ~ r~ ~ tD ~:
0 0 c~ ~ ' E- ~i ,_~
t ~ .Gert~-~/3 The 'oregoing Tables II and III show ~hat nitrogen efficiency was drama~ically increased ~y utilizing urea fGrmaldehyde reaction prcducts containing the critical ~igh levels Gf ~U and ~TU. This transla~es-into reduced rates of applic~tion necessary for 5 equivalent performance or equivalent rates to cbtain superiGr performance as compared to currently availahle slow release nitrogen sources.
.. . . . . ... .. ..
The invention is based in part on the discovery that the short chain ~U and D~TU pclymers have cGnsiderably greater agronornic efficiency than the hisher methylene urea polymers but yet retain the safety and slow release characteristics of the higher pol~ners. Theoretically, it would be desirable, if econornically ~easible, to produce a fertilizer containing only the short chain polymers. The ~ollGwing example is intended tG illustrate ,his conclusion.
Exa~ple ~ -This example shows the nitrcG;en efficiency, agroncrnic safety and slcw release characteristics cf shcrt chained methylene ureas in their pure state.
~0 Chemically, pure met~ylene diurea (~V) and dimet~ylene triurea (~TU~ were prepared using preparative liquid chrGmatography.
concentrated aqueous solution of a mixture of methylene ureas was injected onto a liquid chrcmatography cGlumn with water as the ~obil phase ~200-500 ml/min). Individua~ ~ethylene ureas were ~2r~ collected after detectlon by refractive index. Water was removed by evaporation from fractions collected and purity determined by analytical high pressure liquid chrcmatography, molecular weight ~eterrninations and elemental analysisO
H. ~o GGer~,z--2/3 -~5-These ~GrmulatiGns were applied ~o ~entucky bluegrass at a ra~e o 5 lbs N/100~ S~. ~t. Fig. ~ shows the fresh weight cf lue~rass clippings as affected by urea and the methylen2 urea poly~ers. ~s shcwn in Fi~. 3, urea, methy'lene diurea and ~, dimethylene triurea induced ccmparable growth during the ~irst 28 days of ~he stu~y~ ~owever, on the 35th day, ~he residual charac~eristics of the'~DU and D~TU as ccmpared to urea became appare~ and continued un~il the 5~th day. T~ese di~ferences were statistically significant at the 5% level during mGst of this time 1~ span.
' In Fig. ~, clipping fresh weights were ccmpared using average yield over three week time spans. Pooling the data, irrespective c~ rates (~, 5, 8 lh. ~1000 sq. ft), reduced the variability which ~ay cccur because of environmental stress and pr~vided a mGre 1~ accurate picture of the results. Fig. 4 shows the residual charac~eristics of ~U and ~TU over a 27 week time frame~ DMTU
w25 significantly better than urea at all dates except during the Eirst three weeks. ~DU was similar to urea ~uring the ~irst sl~
~eeks, then was significantiy better than urea during the remainder of the test. ~DU & D~TU both exhibit residual characteristics sigrlificantly superior to urea.
Tahle IV illustrates the safety of short chain methylene urea polymers. 'Jrea, ~DU, D~TU and dimethylGlurea were applied to moist Kentucky Bluegrass at 8 lh N/1000 ft . 3imethylolurea is ~5 one of the reaction intermediates in the methylene urea polymeri~ation. Neither ~DU nor D~TU produced any noticeable injury whereas urea and dimethylolurea gave ccnsiderable injury.
--~S--~ l.M. Go~rtz 2~
-26~ 3~
Table IV
Tolerance of Kentucky Bluegra~s to Urea, Methylene Vraas dlmethylolurea ~ Injury Nitrogen Lbs N/lOOO Days ~f~er Treating Source S~. Ft. 3 7 21 2~
_ __ _ _ _ __ Methylene diurea 8 0 1.7 0 Dimethylene triurea 8 0 0 0 0 Urea B 26.725~0 23.0 14.0 dime-thylolurea 8 30.065.0 5~.0 57.0 Control O O O O O
The inventlon has been illustrated wi~h specific examples of fertilizer compositions. Many o~her nutrients, a~
well as micro-nutrients, and control chemicals ~uch as herbicides, fungicides and insecticides may be combined wi~h ~he products of the invention. Examples of other additives are shown in the aforementioned R~nner U~S. pa-ten~ 3,076,700 and Czurak et al U.S. patent 3,705,794. Other pesticides which may be used are shown in the Pesticide Manual, 6~h Edi~ion~ British Crop Protection Council, 1980. Other herbicides which may be used are shown in Weed Control, 2nd Edition, 1962, Robbins e~
al., McGraw-Hill Book Company, Inc., New York, Ne~ York. Other fer-tilizer nu~rients which may be used in combination are shown in Commercial Fertilizers, 5th Edition, 1955, Collings, McGraw-Hill Book Inc., New York, New York.
Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a controlled release solid fertilizer composition in particulate form comprising the reaction product of urea and formaldehyde, said reaction product containing polymeric nitrogen in the form of methylene urea polymers of varying chain length, the improvement in which at least 60% by weight of the polymeric nitrogen is in the form of cold water soluble nitrogen polymers consisting of short chain polymers selected from the group consisting of methylene diurea and mixtures of methylene diurea and dimethylene triurea.
2 The fertilizer composition of claim 1 containing up to 70% by weight urea.
3. The fertilizer composition of claim 1 containing an inert carrier for said fertilizer.
4. The fertilizer composition of claim 3 in which said carrier is porous and the fertilizer is contained within the pores of said carrier.
5. The fertilizer composition of claim 1 in which the porous carrier is vermiculite.
6. The fertilizer composition of claim 1 containing additional plant nutrients.
7. The fertilizer composition of claim 6 containing phosphorus and potassium plant nutrients.
8. The fertilizer composition of claim 1 containing pesticides,
9. The fertilizer composition of claim I in which at least 45% of the nitrogen consists of cold water soluble reaction products when the amount of cold water insoluble nitrogen is between 15 and 35 percent of the total and more than 35% of the nitrogen consists of cold water soluble reaction products when the percentage of cold water insoluble nitroqen is less than 15%, said percentages being by weight.
10. The fertilizer compositions of claim 9 in which less than 20% by weight of said nitrogen consists of cold water insoluble nitroyen.
11. The fertilizer composition of claim 9 containing an inert carrier for said fertilizer.
12. The fertilizer composition of claim 11 in which said carrier is porous and the fertilizer is contained with the pores of said carrier.
13. The fertilizer composition of claim 12 in which the porous carrier is vermiculite.
14. The fertilizer composition of claim 9 containing additional plant nutrients.
15. The fertilizer composition of claim 14 containing phosphorus and potassium plant nutrients.
16. The fertilizer composition of claim 9 containing pesticides.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/288,457 US4378238A (en) | 1981-07-30 | 1981-07-30 | Controlled release particulate fertilizer composition |
| US288,456 | 1981-07-30 | ||
| US06/288,456 US4411683A (en) | 1981-07-30 | 1981-07-30 | Process of preparing solid controlled release fertilizer composition |
| US288,457 | 1981-07-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1188123A true CA1188123A (en) | 1985-06-04 |
Family
ID=26965027
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000408379A Expired CA1188123A (en) | 1981-07-30 | 1982-07-29 | Controlled release particulate fertilizer composition |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0071128B2 (en) |
| AU (1) | AU552347B2 (en) |
| CA (1) | CA1188123A (en) |
| DE (1) | DE3280087D1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5211985A (en) * | 1991-10-09 | 1993-05-18 | Ici Canada, Inc. | Multi-stage process for continuous coating of fertilizer particles |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1048710C (en) * | 1995-01-23 | 2000-01-26 | 陶金兰 | Insect-proof fungicidal specific mixed fertilizer |
| DE19613794C2 (en) * | 1996-04-04 | 1998-07-23 | Agra Duenger Gmbh | Nutrient substrate for microorganisms in biological soil remediation |
| DE50001797D1 (en) * | 2000-07-04 | 2003-05-22 | Deliplant Gmbh | Process for the production of fertilizer granules |
| CN104310356B (en) * | 2014-09-19 | 2017-02-15 | 贵州大学 | Production method of monopotassium phosphate with by-product welsh onion special fertilizer |
| CN109633008A (en) * | 2018-12-28 | 2019-04-16 | 沈阳中科新型肥料有限公司 | A kind of method of a methylenediourea and dimethylene triurea in detection urea-formaldehyde fertilizer |
| CN113577991B (en) * | 2021-06-29 | 2023-03-21 | 山东联盟化工股份有限公司 | Method for reducing content of methylene diurea in urea product |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1036791A (en) * | 1963-01-21 | 1966-07-20 | Scott & Sons Co O M | Fertilizer compositions and process |
| US3231363A (en) * | 1963-04-08 | 1966-01-25 | O M Scott And Sons Co | Process for making foamed ureaformaldehyde fertilizer |
| GB1180884A (en) * | 1967-06-06 | 1970-02-11 | Allied Chem | Liquid Fertilizer Suspension Containing Ureaform. |
| DE1917569A1 (en) * | 1969-04-05 | 1971-03-25 | Neba Chemie Ag | Process for the production of urea-formaldehyde condensation products |
| IL47144A (en) * | 1975-04-22 | 1978-06-15 | Chem & Phosphates Ltd | Fertilizer compound the ureaform type and a method for the production thereof |
-
1982
- 1982-07-17 DE DE8282106450T patent/DE3280087D1/en not_active Expired - Fee Related
- 1982-07-17 EP EP19820106450 patent/EP0071128B2/en not_active Expired - Lifetime
- 1982-07-26 AU AU86385/82A patent/AU552347B2/en not_active Expired
- 1982-07-29 CA CA000408379A patent/CA1188123A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5211985A (en) * | 1991-10-09 | 1993-05-18 | Ici Canada, Inc. | Multi-stage process for continuous coating of fertilizer particles |
| US5399186A (en) * | 1991-10-09 | 1995-03-21 | Ici Canada, Inc. | Apparatus and process for coating particles |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0071128A3 (en) | 1984-10-17 |
| EP0071128B2 (en) | 1995-08-16 |
| AU552347B2 (en) | 1986-05-29 |
| DE3280087D1 (en) | 1990-02-22 |
| AU8638582A (en) | 1983-02-03 |
| EP0071128B1 (en) | 1990-01-17 |
| EP0071128A2 (en) | 1983-02-09 |
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