A novel kneading element for co-rotating twin-screw extruders (TSE) was invented by designing the disk lobal surfaces in a specific way to create converging flow channels. The polymer melt is forced to pass through the converging channels both in axial and circumferential directions experiencing elongational deformation, which is beneficial for mixing polymers having high viscosity ratio. By using the novel screw elements effective mixing of the polymers and fillers was achieved. It is known that blending polymers having large viscosity difference on conventional co-rotating TSE is a challenge due to their limited dispersive mixing capabilities. According to H. P. Grace, shear does not favor good mixing of polymers having viscosity ratio higher than 4. Poor homogenization leads to product inconsistency, fluctuation of extrusion processes and deterioration of the mechanical properties. In order to achieve efficient dispersion of highly viscous components elongational flow passages have to be created in the processing equipment. The objective of this work was to investigate the influence of a novel screw element on melt homogenization in co-rotating TSE. The mixing zone of a co-rotating TSE ZSK-40 consisted of three sequences with two kneading disks in each. It was observed that the novel kneading disks provide better homogenization of the higher molecular weight polymer and CB masterbatch. It was also found that increasing the screw speed worsens the melt homogenization. GPC analyses confirmed that the Mz and Mz-1 molecular weights of the polymer extruded with the novel kneading disks were significantly higher than those achieved with the standard screw elements.