Surface Haze and Surface Morphology of Blown Film Compositions

Abstract

Reduction in surface haze is a very attractive way to improve the optical properties of most polyolefin films. This route becomes very viable for coextruded multilayer films where the inner layers may be utilized to provide the desired mechanical properties, such as high modulus, controlled shrinkage, and good tear strength while the outer 'skin' layers are utilized to give low surface and total haze values. This study summarizes the effect on surface haze of various such 'skin' layer compositions with a broader goal to produce high clarity and high modulus multilayer blown films. The surface roughness of multilayer films is measured using atomic force microscopy (AFM) and is directly correlated to the measured surface haze of the films.