SOME KEY PROPERTIES OF EBA BASED BLOWN AND CAST FILMS
The viscosity of all thermoplastic melts is non-Newtonian, i.e., the viscosity is a function of the shear rate at which it is tested. For a given polyethylene resin, the relationship between its measured viscosity and the applied shear rate depends on its molecular characteristics. All polyethylene resins are shear thinning. The response of the various types of polyethylene resins to increasing shear is a function of their degree of long-chain branching and molecular weight distribution. Lucofin® 1400HN and Lucofin® 1400MN with their high degree of long-chain branching and broad molecular weight distribution show a shear thinning effect close to that of conventional LDPE. This guarantees a superior processability. In contrast, LLDPE's and other plastomers with a linear structure and narrower molecular weight distribution show a significantly reduced shear thinning effect. As a result, these plastomers only have small processing windows prone to instabilities such as melt fractures and shark skins. Consequently, Lucofin® resins will run much smoother during blown and cast film extrusion.
Melting point and vicat temperature
Tests show the melting points and the vicat temperatures of Lucofin® 1400HN compared to an EVA with similar comonomer content and MFI also compared to a plastomer with similar MFI. Both, the melting points and the vicat temperatures show the highest values for Lucofin® 1400HN. This indicates an excellent maximum service temperature for Lucofin® 1400 HN in end-user products compared to similar competitor's products. All film testing procedures involving elevated temperatures are therefore likely to be passed by formulations based on Lucofin® resins.