Patent ID: 6379497
Filing Date: 2002-04-30
Classification: B65D,D21H

Abstract:
A cellulosic multi-ply paperboard comprising:(a) predominantly cellulosic fibers; (b) bulk and porosity enhancing additive interspersed with said cellulosic fibers in a controlled distribution throughout the thickness of said paperboard; and (c) size press applied binder coating, optionally including a pigment adjacent both surfaces of the paperboard and penetrating into the board to a controlled extent; the overall fiber weight â€œwâ€  of the paperboard being at least about 40 lbs./3000 square foot ream (i) the distribution of the bulk and porosity enhancing additive throughout the thickness of the paperboard, and (ii) the penetration of the size press applied pigment coating into the board, both being controlled to simultaneously produce at a fiber mat density of 3, 4.5, 6.5, 7, 8.3, and 9 pounds per 3000 square foot ream at a fiberboard thickness of 0.001 inch respectively: (A) a GM Taber stiffness of at least about 0.00716 w2.63 grams-centimeter/fiber mat density1.63 pounds per 3000 square foot ream at a fiberboard thickness of 0.001 inch; and (B) at a fiber mat density of about 3 to 9 pounds per 3000 square foot ream at a fiberboard thickness of 0.001 inch, a GM tensile stiffness of at least 1890+24.2 w pounds per inch.