Higher Output Makes LLDPE Film Tougher

Blown film trials done by Nova Chemicals Inc., Moon Township, Pa., show some unique behavior of its first fractional-MI, bimodal Surpass resin.

Blown film trials done by Nova Chemicals Inc., Moon Township, Pa., show some unique behavior of its first fractional-MI, bimodal Surpass resin. This “sLLDPE” is made with Nova’s Advanced Sclairtech dual-reactor process using a non-metallocene, single-site catalyst. Film less than 1 mil thick made from developmental grade EX-FPs016-C with a BUR of 2.5 shows improving MD and TD tear strengths as output increases, whereas standard fractional-MI LLDPE typically shows higher MD orientation and lower MD tear strength at higher output rates. Nova reported the “somewhat surprising” data at the SPE ANTEC meeting in Boston last May. The developmental Surpass grade has a density of 0.916 g/cc, MI of 0.65, and HLMI of 28.8. It also shows better processability than comparable Ziegler-Natta LLDPEs, Nova says. The tests were run with an 8-in. die and IBC. Nova’s commercial film grades of Surpass bimodal sLLDPE have MI of 1.0 or more.