Paper with improved stiffness and bulk and method for making same
First Claim
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1. A paper or paperboard having improved bulk and stiffness comprising:
- a three layered single-ply I-beam structure having a higher density strengthened top layer, a lower density bulked central layer and a higher density strengthened bottom layer, wherein the central layer is a cellulosic core layer, and the top and bottom layers are strengthening 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 such that starch is substantially absent from the central layer, and a bulking agent interpenetrated within the central layer, and wherein the top and bottom layers are formed are from a high strength starch based size-press solution having from about 6 to about 12 wt % starch solids.
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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.
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Citations
23 Claims
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1. A paper or paperboard having improved bulk and stiffness comprising:
- a three layered single-ply I-beam structure having a higher density strengthened top layer, a lower density bulked central layer and a higher density strengthened bottom layer, wherein the central layer is a cellulosic core layer, and the top and bottom layers are strengthening 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 such that starch is substantially absent from the central layer, and a bulking agent interpenetrated within the central layer, and wherein the top and bottom layers are formed are from a high strength starch based size-press solution having from about 6 to about 12 wt % starch solids.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. 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 having from about 6 to about 12 wt % starch solids to form top and bottom coating layers on a top and bottom side of the dried web, and e) drying the size-press treated web to form a three layered single-ply having an I-beam structure comprising a higher density strengthened top layer, a lower density bulked central layer and a higher density strengthened bottom layer, and wherein starch is substantially absent from the central layer.
- View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
Specification