Extrusion International 4-2021

49 Extrusion International 4/2021 SAM North America, LLC www.sam-na.com Nordson Polymer Processing Systems www.nordsonpolymerprocessing.com a build-up of material along the edges of the web, or “edge bead,” that must subsequently be trimmed away as scrap. To ensure that this edge bead consists of the lowest-cost polymer in the coextruded structure, Nordson has devel- oped customizable feedblock inserts that introduce fl ow of the low-cost polymer only at the edges of the structure. The combined materials are then distributed to the fi nal target width in the fl ow channel or manifold of the die. While the encapsulation inserts can be readily retro- fitted into existing EDI feedblocks, Nordson offers new EDI dies equipped with the EPC™ deckle system, which can be adjusted to reduce edge bead formation, and a melt flow system in which the edge encapsula- tion polymer is introduced in the die rather than in the feedblock. The port for introducing the encapsulation polymer moves in concert with the deckle mechanism. “By introducing the encapsulation polymer at this point in the process, the interface between it and the core struc- ture is more de fi ned and the transition overlap between the encapsulation material and the biopolymer material is reduced,” said Iuliano. “The die limits the formation of edge bead and reduces the amount of edge trim.” SAM North America has also developed coextrusion techniques for encapsulating biopolymer structures with LDPE that permit rapid change-over between conventional and biopolymer coatings. The technol- ogy addresses the wide differences in processing prop- erties between the two materials. Andy Christie, man- aging director of SAM North America, will introduce the technology at the Extrusion 2021 Conference, Sep- tember 21 – 23 at the Donald E. Stephens Convention Center, Rosemont, IL. SAMNorth America coextrusion coating and laminating laboratory handles web widths up to 36 in. (914 mm), from fl exibles to board, pre-treated with corona, primer, fl ame or ozone