Adflex and Lucalen resins work in synergy to provide a combination of high elasticity and strong holding forces. They are combined in the core layer of various stretch hood film formulations. Alternatively, the Adflex core layer resin can also be combined with LDPE homopolymer such as Lupolen or Petrothene. Fine-tuning the stretch hood properties to address the performance requirements of end-use applications is done by varying the side-layer composition. In general, side layers are based on metallocene-based LLDPE or high-performance LLDPE according to local availability. For example, in North America Starflex metallocene-based LLDPE resins are commonly used as the component for the film side layers. Both solutions may require additional additives such as Anti-block, Slip and UV (where required) to meet end user requirements. Below are suggested addition levels for each formulation:
Power Stretch: - Side layers - 18000ppm Silica + ~2000ppm Slip. Core Layer - Slip*, and UV if required. (All via Masterbatch).
Clear Stretch: - Side layers - 3000ppm Silica + 700ppm Slip. 2% - 3% PPA** Core Layer – Slip*, and UV if required. (All via Masterbatch).
*If slip is added to Core layer, then slip in Skin layers may not be necessary as an overdose of slip additive can lead to problems on the packaging line, such as film slippage on the roll and misalignment; sealing and cutting issues may also arise.
** Both Satellite extruders should be pre-conditioned prior to running mLLDPE skins to prevent Melt Fracture. Pre-conditioning should be carried out with a 1:1 blend of PPA:mLLDPE and processed at very low screw speeds to allow a thorough coating on the die walls. After pre-conditioning, 2%-3% of PPA should be included in the skin formulation.
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