Rheology and machining performance of waterborne biopolymer labelling adhesives

Machining performance is one of the most important features of waterborne biopolymer labelling adhesives. Various deformation processes on the labelling machine have been analysed in relation to the rheology characteristics of adhesive materials. It has been shown that satisfactory machining performance requires adhesive materials to have particular properties under both shear and extensional deformations. Flow behaviours of commercial labelling adhesive products were tested over a very wide range of shear rate. Time dependences of the apparent shear viscosity were examined at selected shear rates. An adhesive with a smooth flow behaviour and only slight time dependence tends to perform better on the labelling machine. Results found in this work can be used as guide for rheology assessment in the development of new waterborne biopolymer adhesives.