# US 11,441,271 B2 · Paper products and pulps with surface enhanced pulp fibers and increased absorbency, and methods of making same

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- Number: US 11,441,271 B2
- Document ID: US11441271B2
- Status: Granted
- Kind: B2
- Application number: 16/267,755
- Filed: 2019-02-05
- Published: 2019-08-08
- Granted: 2022-09-13
- Earliest claimed: 2018-02-05
- Assignees: Domtar Paper Company, LLC; Miami University
- Applicants: Harshad Pande; Douglas W. Coffin; Mona Alinejad
- Inventors: Harshad Pande; Douglas W. Coffin; Mona Alinejad
- Web page: https://patentgrep.com/patent/US11441271B2

## CPC

- D21H 11/10: Mixtures of chemical and mechanical pulp
- D21D 1/00: Methods of beating or refining; Beaters of the Hollander type (knotter screens D21F)
- D21H 15/02: characterised by configuration
- D21H 25/005: {Mechanical treatment (D21H25/08, D21H25/18 take precedence)}
- D21H 27/002: {Tissue paper; Absorbent paper (D21H21/22, D21H27/02, D21H27/20 take precedence; toilet paper A47K10/00; absorbent pads for physiological fluids A61L15/16; making on paper-making machines D21F11/00)}
- D21H 27/007: {relating to absorbency, e.g. amount or rate of water absorption, optionally in combination with other parameters relating to physical or mechanical properties}
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21D: TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE

## Abstract

Paper products such as tissues can be made using a furnish comprising surface enhanced pulp fibers (“SEPF”). In some embodiments, SEPF have a weighted average fiber length of at least 0.3 millimeters (mm) and an average hydrodynamic specific surface area of at least 10 square meters per gram (m2/g). In some embodiments, a furnish or a paper product can comprise at least 2 % SEPF by dry weight. In some embodiments, a paper product comprising SEPF can be formed from a furnish having a freeness of 650 ml Canadian Standard Freeness (CSF) or less, optionally 600 ml CSF or less.

## Claims

### Claim 1

A method of manufacturing tissue, the method comprising:
mixing at least a first pulp and a second pulp to generate a furnish, wherein:
the first pulp comprises surface enhanced pulp fibers having a length weighted average fiber length of at least 0.3 millimeters (mm) and an average hydrodynamic specific surface area of at least 10 square meters per gram (m2/g);
the second pulp comprises softwood fibers; and
mixing is performed such that the furnish comprises from 10% to 25% surface enhanced pulp fibers by dry weight of fiber in the furnish; and
beating, with a refiner, the furnish such that the furnish has a freeness less than or equal to 650 milliliters Canadian Standard Freeness (ml CSF).

### Claim 2 (depends on 1)

The method of claim 1, wherein beating is performed such that the furnish has a freeness of 600 ml CSF or less.

### Claim 3 (depends on 2)

The method of claim 2, wherein beating is performed such that the furnish has a freeness between 550 ml CSF and 600 ml CSF.

### Claim 4 (depends on 1)

The method of claim 1, wherein mixing is performed such that the furnish comprises between 5% and 25% surface enhanced pulp fibers by dry weight of fiber in the furnish.

### Claim 5 (depends on 1)

The method of claim 1, comprising forming one or more sheets of tissue using the furnish such that the sheet(s) have a grammage between 20 and 45 grams per square meter (g/m2).

### Claim 6 (depends on 1)

The method of claim 1, wherein the softwood fibers of the second pulp comprise Northern bleached softwood kraft fibers.

### Claim 7 (depends on 1)

The method of claim 1, wherein beating is performed such that a decrease in the freeness of the furnish is less than or equal to 300 ml CSF.

### Claim 8 (depends on 7)

The method of claim 7, wherein beating is performed such that a decrease in the freeness of the furnish is less than or equal to 150 ml CSF.