Methods of reducing film thickness variation of bimodal hdpe resins using peroxide treatment

Abstract

Ethylene-based polymers having a high load melt index of 4-15 g / 10 min and a density of 0.94-0.96 g / cm3 are disclosed. These polymers can have one or more of a zero-shear viscosity from 475 to 2000 kPa-s, a relaxation time from 4 to 20 sec, a CY-a parameter from 0.2 to 0.28, a tan δ at 0.1 sec-1 from 1 to 1.5 degrees, and / or from 3 to 10 long chain branches per 1,000,000 total carbon atoms. The ethylene polymers have improved / reduced film thickness variation and are produced by a method that includes a step of melt processing a mixture of a base polymer and a peroxide compound through a die to produce the ethylene polymer. The amount of the peroxide compound is from 1 to 10 ppm by weight of peroxide groups based on the weight of the base polymer (or the ethylene polymer).