Patent ID: 6712936
Filing Date: 2004-03-30
Classification: D21F,D21G,Y10S

Abstract:
A method for manufacturing paper/paperboard, comprising the following steps:(a) manufacturing paper/paperboard product of a particular grade having a first set of respective values for a plurality of material properties that affect fracture toughness; (b) measuring the fracture toughness of said paper/paperboard product; (c) determining that the measured fracture toughness of said paper/paperboard product is different than a desired fracture toughness; (d) determining a second set of respective values for said plurality of material properties that will produce a fracture toughness closer to said desired fracture toughness than was said measured fracture toughness; and (e) manufacturing paper/paperboard product of said particular grade having respective values for said plurality of material properties that are respectively substantially equal to said first set of respective values, wherein said measuring step comprises determining the essential work of fracture, said step of determining a second set of respective values for said group of material properties is performed using a mathematical model of fracture toughness as a function of said plurality of material properties, and said plurality of material properties comprise filler level, softwood pulp content and caliper.