US 12,110,636 B2 · Filter paper

Abstract

Described herein is a filter paper for the production of an aqueous extract, comprising softwood pulp, which has the following properties: a basis weight of more than 9.0 g/m2 and less than 13.5 g/m2, a density of more than 280 kg/m3 and less than 350 kg/m3, a roughness of more than 700 ml/min and less than 1300 ml/min, a bending resistance in the machine direction of more than 50 mN and less than 75 mN, and an air permeability of more than 17000 cm/(min·kPa) and less than 26000 cm/(min·kPa), wherein the filter paper is either free from abacá fibers and sisal fibers or, if abacá fibers and/or sisal fibers are present, taken together they make up less than 20% of the paper mass.

Claims37

Dependent claims

A filter paper for the production of an aqueous extract, comprising softwood pulp, which has the following properties:

a basis weight of more than 9.0 g/m2 and less than 13.5 g/m2,
a density of more than 280 kg/m3 and less than 350 kg/m3,
a roughness of more than 700 ml/min and less than 1300 ml/min,
a bending resistance in the machine direction of more than 50 mN and less than 75 mN, and
an air permeability of more than 17000 cm/(min·kPa) and less than 26000 cm/(min·kPa),
wherein the filter paper is either free from abacá fibers and sisal fibers or, if abacá fibers and/or sisal fibers are present, taken together they make up less than 20% of the paper mass, and
wherein the content of softwood pulp in the filter paper is at least 70% with respect to the mass of the filter paper.

4 more elements

A process for manufacturing a filter paper, which is either free from abacá fibers and sisal fibers, or if abacá fibers and/or sisal fibers are present, taken together, these make up less than 20% of the paper mass, wherein the process comprises the following steps:

suspending softwood pulp in water and refining at least the softwood pulp in a refiner,
delivering a suspension, which contains at least the refined softwood pulp, onto the wire of a paper machine,
de-watering the suspension through the wire of the paper machine to form a paper, and
pressing the paper with a sufficient pressure to provide the paper with the following properties:
a basis weight of more than 9.0 g/m2 and less than 13.5 g/m2,
a density of more than 280 kg/m3 and less than 350 kg/m3,
a roughness of more than 700 ml/min and less than 1300 ml/min,
a bending resistance in the machine direction of more than 50 mN and less than 75 mN, and
an air permeability of more than 17000 cm/(min·kPa) and less than 26000 cm/(min·kPa).

6 more elements

Dependencies are inferred from the claim text.

Filter paper

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Filter paper

Life of this patent

Abstract

Claims37