Microencapsulated trifluralin

Claim 1

A herbicide product comprising an aqueous dispersion of microcapsules of a solution of alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-di(C 1 -C 5 ) alkyl-p-toluidine dissolved in at least 20% up to about 60% of an aromatic petroleum solvent, based on the weight of said solution, said toluidine being present in said dispersion in a phytotoxic amount, said solution microencapsulated within a resinous polycondensate wall selected from the group consisting of polyurea, polyamide and amide-urea copolymers, the weight of said wall ranging from 2.5 to 40% based on the weight of the microcapsule, at least a major proportion of said microcapsules having an average size of at least about 10 up to about 100 microns in diameter, said polycondensate wall prepared by the reaction of first and second polyurea, polyamide or amide-urea copolymer-forming intermediates, at least one of said first and second intermediates containing from 0 to 100 percent, based on the weight of the intermediate, of a polyfunctional reactant which (a) is complementary to the other of said intermediates and effective for crosslinking reaction and (b) has at least three reactive groups that are effectively functional in said reaction, said reactive groups selected from the class consisting of amine, isocyanate, --COCl and SO 2 Cl groups, said intermediate containing at least 5% of said polyfunctional reactant when the weight of the wall is 10% or less, and, said intermediate containing less than 100% of said polyfunctional reactant when the weight of said wall is 10% or greater.