Method of microencapsulating an agricultural active having a high melting point and uses for such materials

Abstract

A method of producing a controlled release form of an agricultural active material includes the provision of an organic liquid composition in which the active is present, but where the liquid composition is free from aromatic solvents and is maintained below the normal melting point of the active. The liquid composition is formed into small droplets and the droplets are enclosed by a non-water soluble shell to provide microcapsules, the shell of which is designed to release the agricultural active at a pre-selected controlled rate when the microcapsule is exposed to natural environmental conditions. Controlled release forms of agricultural actives are also provided.

1 - 91 . (canceled)  
     
     
         92 . A method of modulating the release rate of an agricultural active from a microcapsule containing the agricultural active to obtain a pre-selected controlled release rate of the active, the method comprising 
 providing an organic liquid composition comprising the agricultural active;    forming the liquid composition into small droplets;    enclosing each droplet in a non-water soluble shell to form a microcapsule by dispersing the small droplets of the organic liquid composition in an aqueous liquid which is immiscible with the organic liquid composition; and    forming a non-water soluble shell by interfacial polymerization at the interface of the droplets and the aqueous liquid which shell encloses each droplet as a core of a microcapsule, wherein the shell is designed to release the agricultural active from the microcapsule at a pre-selected controlled rate when the microcapsule is exposed to natural environmental conditions.    
     
     
         93 . The method according to  claim 92 , wherein the organic liquid composition comprises one or more polyisocyanates; 
 the aqueous liquid comprises one or more polyamines; and wherein    the interfacial polymerization comprises reaction of the polyisocyanates and the polyamines at the interface of the droplets and the aqueous liquid.    
     
     
         94 . The method according to  claim 93 , wherein the one or more polyisocyanates comprise 1,12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3-diisocyanate, 2,4- and/or 2,6-hexahydrotoluylene diisocyanate, 4,4′,4″-triphenylmethane triisocyanate, tris-(4-isocyanatophenyl)-thiophosphate, Desmodur N3300 (CAS 104559-01-5; 1,6-diisocyanate homo-polymer), OCN—R—(O—CH 2 CH 2 ) x —R—NCO (polyethylene glycol), OCN—R—(OCH 2 —CH—CH 3 ) n —R—NCO (polypropylene glycol), OCN—R—(OCH 2 CH 2 CH 2 CH 2 ) x —R—NCO (polytetramethylene glycol), OCN—R—(OCH 2 CH 2 OCO—CH 2 CH 2 CH 2 CH 2 —CO) x —R—NCO (polyethyleneadipate), OCN—R—(OCH 2 CH 2 CH 2 CH 2 OCO—CH 2 CH 2 CH 2 CH 2 —CO) n —R—NCO (polybutyleneadipate), OCN—R—(OCH 2 CH 2 CH 2 CH 2 CH 2 CH 2 OCO) x —R—NCO (polyhexamethylene-polycarbonate), where in each case, R can be CH 2  or CH 2 CH 2  or alkyl, HDI, 1,5 Diisocyanatopentane, TMDI, C12DI, 1,6,11-Undecanetriioscyanate, CHDI, BDI, HXDI, IPDI, IMCI, DDI-1410, XDI, m-TMXDI, p-TMXDI, DEBI, HMDI, OCN(CH 2 ) 3 O(CH 2 ) 3 NCO, OCN(CH 2 ) 3 OCH 2 CH 2 O(CH 2 ) 3 NCO, OCN(CH 2 )3OCH(CH3)CH 2 O(CH2) 3 NCO, OCN(CH 2 ) 3 O(CH 2 ) 3 O(CH 2 ) 3 NCO, OCN(CH 2 ) 3 O(CH 2 ) 2 O(CH 2 ) 2 O(CH 2 ) 3 NCO, OCN(CH 2 ) 3 OCH(CH 3 )CH(CH 3 )O(CH 2 ) 3 NCO, OCN(CH 2 ) 3 OCH 2 C(CH 3 ) 2 CH 2 O(CH 2 ) 3 NCO, OCN(CH 2 ) 3 OCH 2 C(Et) 2 CH 2 O(CH 2 ) 3 NCO,  
       
         
           
           
               
               
           
         
       
       OCN(CH 2 ) 3 O(CH 2 ) 4 O(CH 2 ) 3 NCO, OCN(CH 2 ) 3 O(CH 2 ) 6 O(CH 2 ) 3 NCO, 
 OCN(CH 2 ) 3 O(CH 2 ) 10 O(CH 2 ) 3 NCO, PPDI, 2,4-TDI, TDI(80:20), MDI, PMDI, NDI, TODI, and mixtures thereof.  
 
     
     
         95 . The method according to  claim 93 , wherein the one or more polyisocyanates are selected from the group consisting of N,N′,N″-tris(6-isocyanatohexyl)-nitrodotricarbonic triamide and meta-tetramethylenexylylene diisocyanate.  
     
     
         96 . The method according to  claim 95 , wherein the one or more polyisocyanates comprise N,N′,N″-tris(6-isocyanatohexyl)-nitrodotricarbonic triamide and meta-tetramethylenexylylene diisocyanate.  
     
     
         97 . The method according to  claim 93 , wherein the one or more polyamines comprise a polyamine selected from the group consisting of diethylene triamine, triethylene tetramine, tetraethylene pentamine, iminobispropylamines, amine epoxy adducts, alkyldiamines from ethylene diamine to hexamethylene diamine, and trimethylolpropane tris[poly(propylene glycol)amine terminated] ether.  
     
     
         98 . The method according to  claim 93 , wherein the one or more polyamines comprise at least two polyamines selected from the groups consisting of diamines, triamines and tetramines.  
     
     
         99 . The method according to  claim 93 , wherein the one or more polyamines comprise at least one triamine and at least one tetramine.  
     
     
         100 . The method according to  claim 99 , wherein the release rate of the active is modulated by controlling the ratio of the equivalents of triamine to the equivalents of tetramine.  
     
     
         101 . The method according to  claim 93 , wherein the one or more polyamines are selected from the group consisting of diethylene triamine, tetraethylene pentamine, triethylene tetramine, iminobispropylamines, amine epoxy adducts, alkyldiamines from ethylene diamine to hexamethylene diamine, and trimethylolpropane tris(poly(propylene glycol)amine terminated) ether.  
     
     
         102 . The method according to  claim 93 , wherein the one or more polyamines are selected from the group consisting of triethylenetetramine and trimethylolpropane tris[poly(propylene glycol)amine terminated] ether.  
     
     
         103 . The method according to  claim 93 , wherein the one or more polyamines comprise triethylenetetramine and trimethylolpropane tris(poly(propylene glycol)amine terminated) ether.  
     
     
         104 . The method according to  claim 93 , wherein the aqueous liquid comprises water.  
     
     
         105 . The method according to  claim 93  wherein the reaction of the one or more polyisocyanates with the one or more polyamines is carried out at a temperature of between about 25° C. and about 90° C.  
     
     
         106 . The method according to  claim 93  wherein the reaction of the one or more polyisocyanates and the one or more polyamines is carried out at a temperature of between about 40° C. and about 75° C.  
     
     
         107 . The method according to  claim 93  wherein the ratio of the equivalents of polyisocyanates to the equivalents of polyamines is between about 4:1 to about 1:4.  
     
     
         108 . The method according to  claim 93  wherein the ratio of the equivalents of polyisocyanates to the equivalents of polyamines is between about 2:1 to about 1:2.  
     
     
         109 . The method according to  claim 93 , wherein the ratio of the equivalents of polyisocyanates to the equivalents of polyamines is about 1:1.  
     
     
         110 . The method according to  claim 100 , wherein the one or more polyamines omprise at least one triamine and at least one tetramine present in an equivalents ratio of triamine:tetramine of from about 100:0 to about 0:100.  
     
     
         111 . The method according to  claim 100 , wherein the one or more polyamines comprise at least one triamine and at least one tetramine present in an equivalents ratio of triamine:tetramine of from about 20:80 to about 80:20.  
     
     
         112 . The method according to  claim 100 , wherein the one or more polyamines comprise at least one triamine and at least one tetramine present in an equivalents ratio of triamine:tetramine of from about 40:60 to about 60:40.  
     
     
         113 . The method according to  claim 100 , wherein the one or more polyamines comprise at least one triamine and at least one tetramine present in an equivalents ratio of triamine:tetramine of from about 50:50.  
     
     
         114 . The method according to  claim 93 , wherein an emulsifier is also present.  
     
     
         115 . The method according to  claim 114 , wherein the emulsifier is selected from a material comprising a sodium salt of naphthalene sulfonic acid formaldehyde polymer and a sodium salt of maleic acid-olefin copolymer.  
     
     
         116 . The method according to  claim 93 , wherein the pH of the solution is adjusted to between about 4 and about 11 by the addition of citric acid.  
     
     
         117 . The method according to  claim 93 , wherein the pH of the solution is adjusted to between about 5 and about 9 by the addition of citric acid.  
     
     
         118 . The method according to  claim 93 , wherein the pH of the solution is adjusted to between about 7 and about 8 by the addition of citric acid.  
     
     
         119 . The method according to  claim 92 , wherein the weight ratio of the shell to the core is from about 5:100 to about 50:100.  
     
     
         120 . The method according to  claim 92 , wherein the weight ratio of the shell to the core is from about 10:100 to about 40:100.  
     
     
         121 . The method according to  claim 92 , wherein the weight ratio of the shell to the core is from about 15:100 to about 30:100.  
     
     
         122 . The method according to  claim 92 , wherein the microcapsules have an average particle size of from 1μ to 20μ.  
     
     
         123 . The method according to  claim 92 , wherein the microcapsules have an average particle size of from 2μ to 10μ.  
     
     
         124 . The method according to  claim 92 , wherein the microcapsules have an average particle size of from 2μ to 6μ.