Patent ID: 8491755
Filing Date: 2013-07-23
Classification: D21H

Abstract:
1. A method for controlling air permeability in paper and board products such that the air permeability resistance of the paper and board products does not change more than 10% when the amount of a filler consisting at least in part of cellulose or lignocellulose fibrils on which there have been deposited precipitated calcium carbonate particles is increased from 10% by weight to 20% by weight, on the basis of the weight of the precipitated calcium carbonate component of the filler and the weight of the paper and board products, comprising adding to a fiber slush to be formed into the paper and board products, 10% by weight to 20% by weight of the filler consisting at least in part of cellulose or lignocellulose fibrils on which there have been deposited precipitated calcium carbonate particles, the proportion of the deposited precipitated calcium carbonate particles being between 70-85% of the weight of the filler, on the basis of the weight of the precipitated calcium carbonate component of the filler and the weight of the paper and board products.