The Manufacture and Performance of Polyethylene‐Polyisobutylene Films for Cling Applications

Abstract

AbstractA range of Linear Low Density Polyethylene (LLDPE) films with polyisobutylene (PIB) content from 2%‐8% was manufactured using a Killion blown film extrusion system and a cast film extrusion system. The films were aged at 25°, 35° and 45° for up 28 days, to enable tack (cling) development. The tack, in both blown and cast films, improved significantly with ageing, at increased storage temperatures and at higher film blow up ratios. FTIR/ATR analysis was used to investigate the surface migration of PIB in the cast films. The results confirmed those determined by mechanical tack (cling) analysis. DSC analysis showed only a slight decrease in film crystallinity with increasing PIB concentration. The film tensile modulus, elongation and tear properties in both MD and TD were not significantly affected by increase in PIB concentration.A second series of films with 8% PIB content was manufactured from a range of LLDPE'S. FTIR/ATR, DSC and mechanical tack analysis were used to investigate the relationship between polymer properties and migration rates. The study established that crystallinity was the most influential factor governing PIB migration and this could be related to polymer density. Co‐monomer type was found not to be a factor influencing migration of PIB.