Fatty acid esters of cellulose or starch production by reacting the starting material with a fatty acid or ester in a heated twin screw extruder

摘要

Cellulosic and amylaceous materials are rendered hydrophobic by reaction with a fatty acid or fatty acid ester in the presence of a catalyst in a heated twin screw extruder. Process for preparing a fatty ester of cellulose or starch by esterification or transesterification of a cellulosic or amylaceous substance with a fatty reactant comprising a fatty acid or an ester of a fatty acid having one or more acyl groups each with at least 6C, comprises feeding the solid comminuted cellulosic or amylaceous material, the fatty reactant and a catalyst into a twin screw extruder operating with a barrel temperature of 180-230 (190-210) deg C to bring about the grafting reaction (I): Poly-OH + fatty reactant = Poly-O-CO-R + by-product (I) Poly = the polymeric chain of the cellulosic or amylaceous substance. subjecting the reaction mixture to thermomechanical treatment in the twin screw extruder during the (trans)esterification reaction; withdrawing the pasty reaction product from the extruder after a residence time of 1-30 mins.; and isolating the resulting solid fatty ester of cellulose or starch by solvent extraction of the other components of the pasty mixture.