Composites of lignin and biologically active materials

Abstract

The subject invention is directed to composites of lignin and biologically active materials. The composites consist of a biologically active agent dispersed throughout an alkali lignin material in a ratio of .1:1 to 1:10 of the biologically active agent to alkali lignin. The biologically active agent is either entrapped by the lignin macromolecular matrix or held by physical-chemicalforces of van der Waal's, hydrogen bonding or ion association types. The active agent is slowly released on application either by diffusion through the lignin solid, or through degradation or dissolution of the lignin. The composites are obtained by a variety of processes including the coprecipitation-inclusion from an aqueous alkaline lignin solution by adding acid or salts, the drying of a precipitated lignin slurry biologically active agent dispersion, or the elimination of a common solvent from a lignin-biologically active organic agent mixture. The biologically active agent may be incorporated in the lignin matrix at dimensions varying from molecular size to droplet or particle sizes.

What is claimed is:  .[.1. A process for making a controlled release herbicide containing composite which consists essentially of; 
     
       c. drying said precipitated materials..]. 2. The controlled release composite made according to the process of claim .[.1.]. .Iadd.3.Iaddend. . .Iadd. 3. A process for making a controlled release herbicide containing composite which consists essentially of; a. emulsifying an aqueous slurry containing 2-chloroallyl diethyldithiocarbamate and an alkali lignin at a weight ratio of greater than 1:1 to 1:4 of 2-chloroallyl diethyldithiocarbamate to alkali lignin,   b. acidifying said emulsion with a mineral acid to a pH between about 2 and 6, to thereby precipitate said 2-chloroallyl diethyldithiocarbamate/alkali lignin, physically absorbing the 2-chloroallyl diethyldithiocarbamate throughout the alkali lignin matrix to form a micro dispersion, and   c. drying said precipitated materials, said controlled release composite containing an effective amount of herbicide. .Iaddend.