Atmospheric Plasma -- The New Functional Treatment for the Extrusion Coating and Laminating Process, 2003 European PLACE Conference Proceedings

Electrostatic corona pretreatment has traditionally been a very cost-efficient treatment method to optimize adhesion levels during the extrusion coating and lamination process. While it is cost-effective, the residence times may be insufficient to permit penetration of the active species that effect change into the surfaces of web materials. Lowpressure plasmas have been used for many years to surface treat three-dimensional plastic objects and polymer films, therefore, the benefits of plasma treatment are well recognized: reduced degradation of surface morphology, higher treatment (dyne) levels, elimination of backside treatment, and extended life of treatment over time. However, the complexity, slow speed and high cost of these contained plasma systems make them impractical for all but the most esoteric applications. Now a system has been developed that allows plasmas to be sustained at atmospheric pressure in a way that permits the surface treatment of substrates to enhance adhesion strength and hot tack in the extrusion coating and lamination processes on a continuous web handling system similar to a corona treating system. The Atmospheric Plasma Treatment (APT) process allows treatment in a broad range of reactive chemistries and has been successfully tested on various films, foils, nonwovens and metals. Further, depending upon the dyne level required and type of material, line speeds in excess of 400 fpm are practical and up to 1,000 fpm have been achieved. Specialty applications requiring stringent surface morphology specifications, specific surface modification such as hydrophilicity, precise surface coating or tightly controlled electrical characteristics will find the APT system especially attractive and useful.