The featured paper for this quarter is:
Solidification Process in Extrusion Coating
By William M. Karszes, PhD.
*Originally published in 1991
The work to design equipment and resins for the extrusion coater is enormous. The extrusion coater can negate all this work in a fraction of a second by not setting the parameters at the coating station properly. The region from the die, where the polymer is first extruded, to where the material leaves the chill roll is critical for good coatings. In this region, the solidification process occurs and is discussed herein. Attention to detail and an understanding of the interactions in this region will help design, set up, and troubleshoot the coating process. A clearer understanding of this region will hopefully help the processor to produce a quality product consistently, as well as enable the processor to more quickly troubleshoot his problems.
The following papers have been chosen as featured papers in the past, but are still relevant today.
*Originally published in 2020
By: Nicole Whiteman, Industry Manager, NatureWorks LLC Andrea Auchter, Applications Development, NatureWorks LLC , Andrew Christie, Managing Director, SAM North America and Michael Prue, Lab Manager, SAM North America
NatureWorks and Sung An Machinery (SAM) North America researched the extrusion coating process utilizing the incumbent polymer (LDPE) and PLA. Ingeo™ 1102 is a new, compostable, and bio-based PLA grade designed specifically for the extrusion coating process. The research team identified the optimum process parameters for new, dedicated PLA extrusion coating lines. The team also identified changes to existing LDPE extrusion lines that processors can make today to improve output.
The key finding is that LDPE and PLA are significantly different polymers and that processing them on the same equipment without modification of systems and/or setpoints can be the root cause of inefficiencies. These polymers each have unique processing requirements with inverse responses. Fine-tuning existing systems may improve overall output for the biopolymer without capital investment and this study showed an increase in line speed of 130% by making these adjustments. However, the researchers found that the highest productivity can be achieved by specifying new systems for PLA. An increase in line speed of more than 180% and a reduction in coat weight to 8.6 µm (10.6 g/m2 or 6.5 lb / 3000 ft2) was achieved in this study. These results show that Ingeo 1102 could be used as a paper coating beyond cups.