Production of sack paper
First Claim
1. A method of making white sack paper having a grammage of 50-140 g/m2 and a Gurley porosity, per ISO 5636/5, of 2-10 s, comprising the steps of:
- a) providing bleached pulp;
b) subjecting the pulp to high consistency refining and optionally low consistency refining to the extent that the sack paper obtains the Gurley porosity;
c) adding cationic starch to the pulp in an amount of 1.5-4 kg/ton paper; and
d) adding size to the pulp in an amount of 0.4-2.0 kg/ton paper; and
e) forming the sack paper from the pulp,wherein less than 0.5 kg/ton paper of anionic starch is added to the pulp.
1 Assignment
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Accused Products
Abstract
There is provided a method of making white sack paper having a grammage of 50-140 g/m2 and a Gurley porosity (ISO 5636/5) of 2-10 s, comprising the steps of: a) providing bleached pulp, such as bleached sulphate pulp; b) subjecting the pulp to high consistency (HC) refining and optionally low consistency (LC) refining to the extent that the sack paper obtains the Gurley porosity; c) adding cationic polymer, such as cationic starch, to the pulp in an amount of 1.5-5.0 kg/ton paper; and d) adding size to the pulp in an amount of 0.4-2.0 kg/ton paper; and e) forming the sack paper from the pulp, wherein less than 2 kg/ton paper of anionic starch is added to the pulp.
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Citations
15 Claims
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1. A method of making white sack paper having a grammage of 50-140 g/m2 and a Gurley porosity, per ISO 5636/5, of 2-10 s, comprising the steps of:
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a) providing bleached pulp; b) subjecting the pulp to high consistency refining and optionally low consistency refining to the extent that the sack paper obtains the Gurley porosity; c) adding cationic starch to the pulp in an amount of 1.5-4 kg/ton paper; and d) adding size to the pulp in an amount of 0.4-2.0 kg/ton paper; and e) forming the sack paper from the pulp, wherein less than 0.5 kg/ton paper of anionic starch is added to the pulp. - View Dependent Claims (2, 3, 4)
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5. A white sack paper having a grammage of 50-140 g/m2 and a Gurley porosity, per ISO 5636/5, of 2-10 s formed from a bleached pulp to which:
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cationic starch was added in an amount of 1.5-4 kg/ton paper; size was added in an amount of 0.4-2.0 kg/ton paper; and less than 0.5 kg/ton paper of anionic starch was added, and which pulp was subjected to high consistency refining and optionally low consistency refining to the extent that the sack paper obtained the Gurley porosity. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification