Folded window blinds mfr. - using cavity forming webs of different fusion temp. material to prevent through welds

摘要

The Parent Patent described a method of joining the web areas with the size walls of folding window blinds by a welding process. The welded seams or spots are prevented from passing through the entire laminate by using for the webs two layers of materials with different fusion temperature. The web material is unwound from a reel, cut in strips and brought together with one side wall foil of radiation permeable material; with a higher fusion temperature (polycarbonate) which is welded first to the webs of the same material. In the next stage, a side wall foil of a lower fusion temperature (polypropylene) is welded to the web of the same material. This saves special release layers to prevent through welds.