Paper with improved stiffness and bulk and method for making same
AssigneeInternational Paper Company
InventorsAgne Swerin, Jay C. Song, Ladislav Bednarik, Peter R. Lee, Michael Herman, Sen Yang
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Abstract
The invention provides a three layered reprographic paper having improved strength, stiffness and curl resistance properties, and a method for making same. The paper has a central core layer made largely of cellulose and bulked with a bulking agent such as a diamide salt. A starch-based metered size press coating is pressed on both sides of the core layer, wherein the starch has a high solid content. The coating forms a three layered paper having an I-beam arrangement with high strength outer layers surrounding a low density core.
Claims26
A paper or paperboard having improved bulk and stiffness comprising:
- a three layered single-ply I-beam structure having a top layer, a central layer and a bottom layer, wherein the central layer is a cellulosic core layer, and the top and bottom layers are starch based, size-press applied coating layers that cover an upper and lower surface of the central layer with minimal penetration into the central layer, and
- a bulking agent interpenetrated within the central layer.
A paper or paperboard having improved bulk and stiffness comprising:
- a three layered single-ply I-beam structure having a top layer, a central layer and a bottom layer, wherein the central layer is a cellulosic core layer, and the top and bottom layers are starch based, size-press applied coating layers that cover an upper and lower surface of the central layer, a starch coat weights of each of the top and bottom coating layers being between 2 and 10 g/m2, and
- a bulking agent interpenetrated within the cellulosic core layer
A method for making a paper or paperboard comprising the steps of:
- a) providing a furnish including cellulosic fibers and a bulking agent,
- b) forming a fibrous web from the papermaking furnish,
- c) drying the fibrous web to form a dried web,
- d) size-press treating the dried web with a high strength starch based size-press solution to form top and bottom coating layers on a top and bottom side of the fibrous web, and
- e) drying the fibrous web after the size-press treatment to form a three layered single-ply having an I-beam structure.
Dependencies are inferred from the claim text.