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US 12,157,974 B2Granted
Paper production
AssigneeBillerudkorsnas AB
InventorFredrik Nordstrom
Life of this patent
Estimating the term…
Abstract
There is provided a method of producing a paper, comprising the steps of: a) providing a pulp having a Schopper-Riegler (SR) number measured according to ISO 5267-1:1999 of 25-50, which pulp comprises at least 70% by weight sulphate or sulphite pulp; b) diluting the pulp to a consistency of 0.1%-0.9%; and c) forming a web from the diluted pulp from step b) in a forming section at a machine speed of at least 1100 m/min, such as 1100-1800 m/min.
Claims15
A method of producing a paper, comprising the steps of:
- a) providing a pulp having a Schopper-Riegler (SR) number measured according to ISO 5267-1:1999 of 25-50, which pulp comprises at least 70% by weight sulphate or sulphite pulp wherein step a) comprises subjecting a starting pulp to low consistency (LC) refining to obtain the pulp having a Schopper-Riegler (SR) number measured according to ISO 5267-1:1999 of 25-50;
- b) diluting the pulp to a consistency of 0.1%-0.9%;
- and c) forming a web from the diluted pulp from step b) in a forming section at a machine speed of at least 1100 m/min and wherein the method further comprises the steps of pressing the web from step c), drying the pressed web in a drying section to obtain a dried web having a moisture content of 4%-7%, impregnating the dried web with a water-based composition comprising polyvinyl alcohol, and subjecting the impregnated web to drying and calendaring.
Dependencies are inferred from the claim text.