LLDPE/PP Blends in Tubular Film Extrusion: Recycling of Mixed Films

Mixtures of film grade LLDPE, LDPE, and PP may occur in recy cle streams. Household plastic films collected through a recycling program were found to contain less than 2 per cent PR The present study concerns the effects of minor amounts of polypropylene on the film properties of such mix tures. Polypropylene enhances film stiffness slightly and has no deleterious ef fect on other PE film properties at levels up to 5 per cent PP However, consider able degradation of tear and impact strength occurs with higher polypropylene concentrations. These problems are alleviated by addition of a vinyl acetate EVA film grade polymer of 28% VA content, which will permit PP levels ap proaching 20 per cent without negative impact on film properties. Good proper ties were observed in 85/15 LLDPE/PP mixtures by addition of 5 per cent of this EVA, based on the total polyolefin content. This report gives a detailed descrip tion of the mechanical properties of the extruded films.