Patent ID: 8440125

Claim:
A method comprising the steps of: receiving a high stalk, high density polyethylene (HDPE) film from a blown-film line orienting in the machine direction the high stalk, high density polyethylene (HDPE) film wherein the orienting step further comprises the steps of: heating the high stalk, high density polyethylene film using a plurality of heating rollers to an orientation temperature to produce a heated film, wherein the orientation temperature is between (i) 60% of the difference between the glass transition temperature and the melting temperature; and, (ii) the melting temperature; feeding the heated film into a plurality of rollers wherein the plurality of rollers stretches the film on a continuous basis to produce a stretched film; annealing the stretched film to produce an annealed film; and, cooling the annealed film wherein the cooled film has a machine direction tensile strength at yield greater than 69,000 psi and a draw-down ratio greater than or equal to 11:1, wherein the HDPE has a density greater than 0.940 g/cm 3 , the HDPE has a weight average molecular weight (Mw) within the range of 150,000 to 500,000, the HDPE has a number average molecular weight (Mn) within the range of 11,000 to 20,000, and the HDPE has a molecular weight distribution (Mw/Mn) within the range of 9 to 20.