Analysis of Multi Layer Blown Film Properties (PART 1)

摘要

Blown and cast film coextrusion is growing in popularity due to an increased impetus towards the reduction in rawrnmaterial costs. In addition it is a well known fact that coextrusion provides advantages in terms of a film’s physicalrnproperties. This is to say that multi layer film properties have long been known to outperform less advanced films ofrnfewer layers in terms of economics and properties traits.rnLittle, if any, qualitative film properties data is available to support the above statement. This paper will describe anrnongoing study whose purpose will be shed light on the subject by providing a basis for the analysis of two seeminglyrnequivalent coextruded 5 material component films that were manufactured on different blown film dies designs. Thernonly variable changed was the overall number of film layers. Initial data was collected to this effect and will bernpresented here.rnThe goal of the experiment is to collect films from two 5 layer dies of the same layflat, thickness and materialrncomposition. One of the films is to have double the number of layers than the other. The layer doubling wasrnachieved through layer splitting, a process that is inherent to the Dual Spiral System (DSS) die design, where eachrnindividual layer is dividing into two separate layers and then recombined. This means that a five extruder DSS diernwould in fact be producing a 10 layer structure.