Study On Rheological Property Of White Masterbatch With LLDPE/LDPE

For the blends of color masterbatch and its colored plastic, they melted before molding, like most polymer. A melted solid flowed with distortion, so the rheological property of melted system directly affected its processasibility and the product application. The rheological property of molten color masterbatch and its colored plastic had an important effect on processasibility and application of plastic.The blends of linear low density polyethylene with high melt flow rate and low density polyethylene was choosen to be the carrier resin of white masterbatch. The carrier resin of the white masterbatch was the blends of LLDPE and LDPE, with different blending ratios. Meanwhile, the percents of titanium pigment in masterbatch were different. The effects of different blending ratios of carrier resin on the color performance, hiding power and processing rheology of white masterbatch were investigated. It showed that when the blending ratio of carrier resin was 1, the whiteness and hiding power would be the maximum, for the white masterbatch with 60wt % TiO₂.With the melt flow indexer and cone plate rheometer, white masterbatch with carrier resin of blending ratio of 1 were investigated. It was found that the masterbatch belonged to the typical non-Newtonian fluid. When the mass percentage of titanium dioxide was higher, the fluidity of the masterbatch was worse, and the apparent viscosity was higher. The shear stress and apparent viscosity of the masterbatch decreased with the increase of the shear rate and temperature. The storage and loss modulus increased followed the increase of the angle frequency, but the slopes were different. White masterbatch was sensitive to temperature. The activation energy was about 30kJ/mol. There was an equal viscosity of masterbatch and LDPE. It was helpful to confirm the processing parameters.Non-Newton index and consistency index were investigated. They indicated the sensibility of viscosity to shear rate and viscosity of white masterbatch. It was useful for us to make sure the processing condition and application.