Process and apparatus for coating paper

Abstract

A process for effecting the high speed coating (as herein defined) of both sides of a lightweight paper sheet (as herein defined) with coatings of low dry coatweight (as herein defined), while maintaining good coating pattern and control over the degree of curl in the sheet when dried, comprising the steps of: moving an endless transfer surface sequentially through first, second and third stations, at first station, forming on said transfer surface a smooth continuous film of a first coating mix having a predetermined fluid content and rheology, at the second station, bringing a first side of said paper sheet into contact with said transfer surface and simultaneously subjecting the sheet to pressure against said transfer surface without substantial sheet distortion, so as to promote substantially complete absorption by the sheet of the solvent or dispersion medium of the first coating mix while in engagement with the transfer surface and prior to passage of the sheet and transfer surface through the third station. at the third station, applying to the second side of the sheet a second coating mix having a predetermined fluid content and rheology optionally differing from that of the first coating mix, and separating the sheet from the transfer surface for drying.

Dependencies are inferred from the claim text.