Westvaco Corporation

Humbert T Dellicolli

Peter Dilling

Sten I Falkehag

Disclosed herein are cross-linked lignin gels which have been found useful as pesticide carriers in controlled release pesticide systems. The carrier is a highly reswellable cross-linked lignin gel prepared by reacting alkali lignin with from 1 mole to 10 moles of cross-linking agent, such as formaldehyde, per 1,000 grams of lignin. An aqueous solution of lignin and the cross-linking agent is reacted at elevated temperatures until cross-linking occurs to the point where a discernible increase in viscosity takes place and the gel is formed. The gels are allowed to dehydrate, and the pesticide in an amount from 0.1:1.0 to 2:1 (pesticide to carrier) is included by reswelling the dehydrated gel in an aqueous solution of the pesticide.

Cross-linked lignin gels

A sustained release composition is disclosed which provides an improved carrier for an organic pesticide. The improved carrier is a reversibly swellable lignin gel made by cross-linking an alkali lignin with epichlorohydrin using particular conditions.

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Charleston, SC, United States of America

Humbert T Dellicolli