Method and apparatus for drying coated sheet material
US4365423A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 1981 |
| Grant date | Dec 28, 1982 |
| Priority date | — |
| Expiry date | Mar 27, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2001/7485
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In the drying of sheet materials which have been coated with a layer, or with two or more superposed layers, of liquid coating composition, improved drying conditions which result in less formation of mottle are provided by the use of a foraminous shield, such as a screen or perforated plate, located in close proximity to the coated surface. The sheet material, for example a web of paper or polymeric film or a succession of discrete sheets of paper or polymeric film is conveyed through a drying zone, along a predetermined path, while a gaseous drying medium, such as air maintained at an elevated temperature, which serves to promote evaporation of the liquid medium in the coating composition, is directed through the foraminous shield onto the coated surface. The foraminous shield functions to promote uniform heat transfer conditions and restricts the extent to which spent gaseous drying medium, which is discharged from the drying zone, comes into contact with the surface of the coating, thereby minimizing mottle formation. While the foraminous shield is useful in any drying operation in which mottle formation is a problem, it is especially advantageous in the drying of photographic …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.