Patent ID: 10975522

Abstract:
The invention concerns a method of manufacturing paper or board, the paper or board obtained by the method, and a method of producing a tray from the board. In a fibrous stock for papermaking is incorporated an amount of polymer coated fibrous particles, which even have a foaming agent such as moisture contained therein. A web is formed from the fibrous stock on a forming fabric of a paper or board machine, followed by pressing and drying to a finished paper or board. As the paper or board is sufficiently heated the foaming agent within the particles evaporates, causing expansion and foaming of the polymer coating, which adds to malleability of the board as it is moulded into a shaped article such as a board tray. The invention even covers production of doubly coated fibrous particles for use in said methods, the inner coating layer being of a foamable polymer with a higher melt flow rate and the outer coating layer being of a non-foaming polymer of a lower melt flow rate.