Micro-Environment Control for Slot Die Coating
By precisely matching process variables, such as flow rate, line speed, and vacuum pressure with slot die coating fluid and web substrate properties such as viscosity, surface tension, and adhesiveness, WebFlight slot die coating systems enable maximum slot die coating productivity.
By isolating the slot die coating fluid from the surrounding atmosphere, rheological characteristics remain constant throughout the slot die coating run, which means fewer adjustments of all other process variables. In addition, emissions of VOC’s are minimized and easily vented.
Atmospheric Pressure Control
Reduction of the atmospheric pressure in the vacuum chamber creates a low-pressure fluid eddy on the upstream side of the applicator opening, which serves two purposes. First, it primes the web with coating fluid ahead of the die slot, effectively enlarging the fluid stream, thereby facilitating adhesive and cohesive bonding to the substrate. Second, it acts as an air dam, diverting residual boundary layer air away from the injection point and into the vacuum chamber.
Adhesive Slot Die Coating Process Optimization
WebFlight slot die coating technology’s precision controls facilitate extreme uniformity of fluid deposition, higher line speeds, less down time, less solvent usage and greater throughput for virtually any combination of web materials and coating fluids.
Frontier Patch Coating Technology
In many applications, it is desirable to have an area of un-coated substrate around the perimeter of a coating. With Frontier’s Patch Coating Technology, a slot die is used to deposit distinct rectangular patches of coating. The patch size and spacing can easily be controlled in both the cross web and machine directions to within 0.50 mm. Thickness of the patches can be controlled to within +/-4%, which includes leading and trailing edges. In the laboratory, Frontier has attained thickness precision to within +/-2.5%.