Low volatility formulations of microencapsulated clomazone
First Claim
1. A process for the preparation of herbicidally effective formulations of clomazone having a volatility less than fifty percent of the volatility of an emusifiable concentrate of clomazone containing four pounds of clomazone per gallon of formulation which comprises microencapsulating the clomazone by interfacial polymerization by the steps of:
- a) providing an aqueous phase containing 0.3 to 3.0 wt. % of one or more emulsifiers;
optionally 0.02 to 0.20 wt. % of a xanthan gum viscosity modifier/stabilizer, and 0.1 to 1.0 wt. % of an antifoam agent;
b) providing a water immiscible phase consisting of clomazone, polymethylene polyphenyl isocyanate (PMPPI), and a hydrocarbon solvent;
the weight ratio of clomazone to PMPPI being in the range of 1;
1 to 6;
1;
c) emulsifying the water immiscible phase in the aqueous phase, forming a dispersion of water immiscible droplets throughout the aqueous phase;
d) agitating the dispersion while adding thereto an aqueous solution of 15 to 100 weight percent of at least one polyfunctional amine selected from ethylenediamine (EDA), diethyltriamine (DETA), triethylenetetramine (TETA), and 1,6-hexanediamine (HDA), with the proviso that (EDA) is used only in a mixture, the weight ratio of polyfunctional amine to PMPPI being in the range of 0.1;
1 to 1;
1, thus forming microcapsules having a polyurea shell wall around the water immiscible droplets;
e) curing the microcapsules by continuing the agitation while heating the dispersion at a temperature in the range of 35°
to 60°
C. for a period of 3 to 10 hours to produce a formulation in which the average size of the microcapsules is in the range of 5 to 50 microns;
f) optionally adjusting the pH to between 6.5 and 9.0.
3 Assignments
0 Petitions
Accused Products
Abstract
An herbicidal composition containing from 1 to 4 pounds of clomazone per gallon of formulation and having a clomazone volatility less than fifty percent of that of an emulsifiable concentrate containing four pounds of clomazone per gallon of formulation is prepared by the interfacial reaction of polymethylene polyphenyl isocyanate with a polyfunctional amine selected from ethylenediamine, diethylenetriamine, triethylenetetramine, 1,6-hexanediamine, and their mixtures in an aqueous phase optionally containing from 0.05 to 0.25 weight percent of a xanthan gum viscosity modified/stabilizer. Several such formulations and the method of their preparation are described.
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Citations
14 Claims
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1. A process for the preparation of herbicidally effective formulations of clomazone having a volatility less than fifty percent of the volatility of an emusifiable concentrate of clomazone containing four pounds of clomazone per gallon of formulation which comprises microencapsulating the clomazone by interfacial polymerization by the steps of:
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a) providing an aqueous phase containing 0.3 to 3.0 wt. % of one or more emulsifiers;
optionally 0.02 to 0.20 wt. % of a xanthan gum viscosity modifier/stabilizer, and 0.1 to 1.0 wt. % of an antifoam agent;b) providing a water immiscible phase consisting of clomazone, polymethylene polyphenyl isocyanate (PMPPI), and a hydrocarbon solvent;
the weight ratio of clomazone to PMPPI being in the range of 1;
1 to 6;
1;c) emulsifying the water immiscible phase in the aqueous phase, forming a dispersion of water immiscible droplets throughout the aqueous phase; d) agitating the dispersion while adding thereto an aqueous solution of 15 to 100 weight percent of at least one polyfunctional amine selected from ethylenediamine (EDA), diethyltriamine (DETA), triethylenetetramine (TETA), and 1,6-hexanediamine (HDA), with the proviso that (EDA) is used only in a mixture, the weight ratio of polyfunctional amine to PMPPI being in the range of 0.1;
1 to 1;
1, thus forming microcapsules having a polyurea shell wall around the water immiscible droplets;e) curing the microcapsules by continuing the agitation while heating the dispersion at a temperature in the range of 35°
to 60°
C. for a period of 3 to 10 hours to produce a formulation in which the average size of the microcapsules is in the range of 5 to 50 microns;f) optionally adjusting the pH to between 6.5 and 9.0. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A process for the preparation of herbicidally effective formulations of clomazone having a volatility less than fifty percent of the volatility of an emusifiable concentrate of clomazone containing four pounds of clomazone per gallon of formulation which comprises microencapsulating the clomazone by interfacial polymerization by the steps of:
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a) providing an aqueous phase containing 0.5 to 3.0 wt. % of one or more emulsifiers;
optionally 0.05 to 0.20 wt. % of a xanthan gum viscosity modifier/stabilizer, and 0.3 to 1.0 wt. % of an antifoam agent;b) providing a water immiscible phase consisting of clomazone, polymethylene polyphenyl isocyanate (PMPPI), and a hydrocarbon solvent;
the weight ratio of clomazone to PMPPI being in the range of 1;
1 to 6;
1;c) emulsifying the water immiscible phase in the aqueous phase, forming a dispersion of water immiscible droplets throughout the aqueous phase; d) agitating the dispersion while adding thereto at least one polyfunctional amine selected from diethyltriamine (DETA), triethylene-tetramine (TETA) and 1,6-hexanediamine (HDA), the weight ratio of polyfunctional amine to PMPPI being in the range of 0.1;
1 to 1;
1, thus forming microcapsules having a polyurea shell wall around the water immiscible droplets;e) curing the microcapsules by continuing the agitation while heating the dispersion at a temperature in the range of 35°
to 60°
C. for a period of 3 to 10 hours;f) optionally adjusting the pH to between 6.5 and 9.0.
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9. An herbicidal composition containing from 1 to 4 pounds of clomazone per gallon of formulation and having a volatility less than fifty percent of the volatility of an emusifiable concentrate of clomazone containing four pounds of clomazone per gallon of formulation, comprising:
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a) an aqueous suspension of microcapsules made up of a polyurea shell surrounding a core of clomazone and a minor amount of a hydrocarbon solvent, the polyurea having been formed from the interfacial reaction of polymethylene polyphenyl isocyanate (PMPPI) with ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), or 1,6-hexanediamine (HDA), or a mixture of the polyfunctional amines, with the proviso that EDA is used only in a mixture; b) 0.2 to 1.00 wt. % polyvinyl alcohol; c) 0.1 to 0.5 wt. % antifoam agent; d) optionally 0.07 to 0.30 wt. % xanthan gum viscosity modifier/stabilizer; and e) 0.75 to 7.0 wt. % propylene glycol, the average size of the microcapsules being in the range of 5 to 50 microns and having a suspensibility of greater than 70%, a viscosity of 1700 to 3800 cps, and a 100 mesh wet screen analysis of greater than 99.95%. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification