Two new families of “enhanced” hexene-copolymer LLDPE resins for blown film are said to offer excellent impact resistance and outstanding hot-tack and heat-seal properties. One resin family reportedly can replace high-end octene LLDPE while the other is said to equal or surpass the performance of VLDPE or metallocene LLDPE (mLLDPE).
New Vytek and Dynex LLDPE families from Chevron Phillips Chemical Co., Houston, are produced using proprietary Energx catalyst technology licensed from Eastman Chemical Co., along with BP Amoco’s Innovene gas-phase reactor technology. “This combination enables us to produce cleaner, more consistent products with fewer gels than other high-performance LLDPEs on the market,” says Richard Schmidt, Chevron Phillips market-development specialist.
Going after octene LLDPE
The two new resin families boast similar overall properties, but their levels of performance differ. Vytek resins reportedly offer improvements over conventional hexene and octene LLDPEs. They can compete with higher-end octene grades but are priced comparable to standard octene LLDPE film resins, according to Schmidt. The accompanying graph shows dart impact of one Vytek grade that is intermediate between levels of standard and high-end octene LLDPEs. A second Vytek grade trades higher impact for lower hot-tack and heat-seal properties. Both are said to have tear strength and optics similar to hexene and standard octene LLDPE.
Vytek is aimed at industrial liners, consumer liners, and heavy-duty sacks. Nine of a planned 14 Vytek grades are now commercially available. All have a density of 0.917 g/cc and all contain processing aid. Four have 0.5 MI and five have 0.85 MI. A variety of slip and antiblock levels are available.
Competition for mLLDPE
Dynex resins are positioned to compete with mLLDPE and VLDPE film resins, and are therefore priced competitively. Says Schmidt, “They have certain properties that equal or surpass those of ExxonMobil’s Exceed mLLDPE and Dow Plastics’ Elite mLLDPE film resins. They have similar processability, lower hot-tack initiation temperature, and very good tack and seal strength.” Tear strength and optics are also reportedly better for Dynex.
Targeted packaging applications include poultry, snack foods, stand-up pouches, fresh produce, and frozen foods. Six of the planned 17 Dynex grades are now available. Three have 0.916 density and 0.85 MI. The other three have 0.917 density and MI of 0.50 or 0.40. All grades contain processing aid and have a range of slip and antiblock levels.