Modification of rheological properties of LDPE for coating applications

The effect of shear modification and blending on the coating performance of a commercial LDPE resin was studied. Shear modification of the virgin resi n as well as of its blends with another LDPE was performed in single- and t win-screw extruders. The rheological properties of the modified materials w ere measured, and no significant differences in their behavior under shear deformation were detected. On the other hand, changes in the entrance press ure drop and extensional viscosity were observed. These changes in extensio nal behavior were found to affect coating properties. Overall, neck-in impr oved through shear modification, whereas it was not sensitive to blending w ith a higher-molecular-weight resin. On the other hand, blending had an eff ect on the draw-down speed, and it can be used to achieve a balanced coatin g performance.