Method for the continuous production of a co-extruded heat-shrinkable composite foamed resin sheet

摘要

This invention relates to the treatment of plastic sheet material and especially co-extruded sheet of orientable plastic material which is comprised of film and foam layers which are continuously stretched in a longitudinal direction. The stretching is effected between a pair of rolls which are maintained at different temperatures and rotated at different rates of rotation to effect a cold stretching of the film-foam laminate to improve its shrink capability and lower its shrink temperature upon usage in various packaging applications. A preferred material is polyethylene which is co-extruded into a laminate of film and foam layers and which exhibits improved shrinkage characteristics when employed in the form of tubular sleeves for container labels or bands.