Method for multilayer coating using pressure gradient regulation
US5728430A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05C9/06
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method for simultaneously coating multiple thin layers of relatively viscous fluids comprises the adjustment of the pressure gradients in the interface region between two confluent flows. In particular, the pressure gradient along the middle lip is regulated so as to not be excessively positive, in order to position the separating line of the top flow at a particular point on the die lips, thus enhancing stable flow. In one aspect of the method, a step configuration is designed into the die lips so that the downstream lip steps away from the web in the direction of web travel. In another aspect of the method, the pressure gradient at various locations in the bead is controlled by beveling the upstream and downstream lips. In yet a further aspect of the present method, the viscosities of the two liquids being coated are matched at the relevant shear rates to promote good coating quality.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.