Abstract: The specification discloses a method for laminating a synthetic film or sheet to a fibrous web. According to the method, a heat-softenable material is combined as a sheet, film, spray or powder with a continuous fibrous web in interfacial contact with fibers of the fibrous web to form a composite. The composite is then continuously conducted through an extended nip dryer where heat and pressure are applied to the composite to effect a substantial reduction in moisture content of the composite while plasticizing the heat-softenable material so that at least a mechanical bond is formed between the material and the fibers of the web characterized by an intermingling of the fibers and the heat-softenable material.

Abstract: Stiffness improvements for multi-ply paperboard laid from chemically pulped softwood and hardwood papermaking furnish are obtained by fiber fractionating the softwood pulp and repositioning the resulting fractions. Chemically pulped and preferably bleached softwood fiber "rejects" of a fractionation screen are redistributed into the outer plies of a three-ply, 300-350 g/m (approximately 195 #/3,000 ft.) basis weight paperboard. The fractionation "accepts" are repositioned to the center ply for a 12% to 15% increase in Taber stiffness. The short, "accept" fiber from the fractionation screen is mixed with chemically pulped hardwood fiber or modified mechanical pulp of either species for formation of the center ply on a multiformer paper machine.

Abstract: Stiffness improvements for multi-ply paperboard laid from chemically pulped softwood and hardwood papermaking furnish are obtained by fiber fractionating the softwood pulp and repositioning the resulting fractions. Chemically pulped and preferably bleached softwood fiber "rejects" of a fractionation screen are redistributed into the outer plies of a three-ply, 300-350 g/m (approximately 195 #/3,000 ft.) basis weight paperboard. The fractionation "accepts" are repositioned to the center ply for a 12% to 15% increase in Taber stiffness. The short, "accept" fiber from the fractionation screen is mixed with chemically pulped hardwood fiber or modified mechanical pulp of either species for formation of the center ply on a multiformer paper machine.