Plasma Pre-treated Cellulose Pulp Sheets for Knot Reduction

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Solution Overview

Problem

Conventional methods for producing crosslinked cellulose pulp fibers result in high knot content, especially at increased production rates, leading to reduced hammermilling efficiency and increased sheet breaks.

Innovation Solution

Plasma pre-treatment of the pulp sheet, specifically using corona discharge, dielectric barrier discharge, or atmospheric pressure glow discharge, to enhance the penetration of crosslinking agents and reduce hydrogen bonding, allowing for faster production with lower knot content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional wetting and hammermilling methods are used to produce crosslinked cellulose pulp fibers, then crosslinking is achieved, but knot content increases significantly reducing hammermilling efficiency

Engineering Contradiction:
Improveknot contentVSAvoidhammermilling efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies plasma treatment to the cellulose pulp fibers before crosslinking to pre-modify the fiber surface properties. This preliminary action reduces hydrogen bonding between fibers, ensuring that when hammermilling occurs later, fibers separate more easily and knot formation is minimized, thus maintaining high hammermilling efficiency while achieving low knot content

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical and chemical parameters of the fiber surface through plasma treatment, specifically modifying surface energy and reducing inter-fiber hydrogen bonding. This parameter change allows fibers to remain separate during subsequent processing, preventing knot formation while maintaining productivity

Inventive Principle:
Principle #35Parameter changes

2Productivity

If production rate is increased using conventional methods, then productivity improves, but knot content increases and sheet breaks increase

Engineering Contradiction:
Improveproduction rateVSAvoidsheet break rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Plasma treatment is applied beforehand to reduce fiber-fiber adhesion through hydrogen bonding reduction. This preliminary modification ensures that even at high production rates, fibers remain separable and sheet integrity is maintained, preventing sheet breaks while achieving high productivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The plasma treatment creates a preliminary anti-adhesion effect between fibers by modifying surface properties and reducing hydrogen bonding. This pre-established anti-adhesion state prevents the harmful effect of fiber clumping and sheet breaking that would normally occur at high production rates

Inventive Principle:
Principle #9Preliminary anti-action

3Manufacturing precision

If crosslinking agent penetration is enhanced to reduce knots, then manufacturing precision improves, but process complexity increases

Engineering Contradiction:
Improveknot contentVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or chemical preprocessing methods with plasma treatment, which uses ionized gas to modify fiber surfaces. This substitution achieves effective crosslinking agent penetration and reduced knot content through a relatively simple, controllable process that doesn't require complex equipment or multiple processing steps

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The plasma pre-treatment significantly reduces knot content in crosslinked cellulose pulp fibers to less than 25%, 20%, or 15% based on sonic fractionation tests, enabling higher production rates without increasing sheet breaks.

Implementation Method 1

Plasma pre-treatment of the pulp sheet, specifically using corona discharge, dielectric barrier discharge, or atmospheric pressure glow discharge, to enhance the penetration of crosslinking agents and reduce hydrogen bonding

Methodology Applied
Scientific EffectHydrogen bonding:

Implementation Method 2

Plasma pre-treatment of the pulp sheet, specifically using corona discharge, dielectric barrier discharge, or atmospheric pressure glow discharge

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Implementation Method 3

Plasma pre-treatment of the pulp sheet, specifically using corona discharge, dielectric barrier discharge, or atmospheric pressure glow discharge

Methodology Applied
Scientific EffectDielectric barrier discharge:

Implementation Method 4

Plasma pre-treatment of the pulp sheet, specifically using corona discharge, dielectric barrier discharge, or atmospheric pressure glow discharge

Methodology Applied
Scientific EffectAtmospheric pressure glow discharge:

Data Source

PatentUS8475631B2Reduction of fiber knots of cellulose crosslinked fibers by using plasma pre-treated pulpsheets
Publication Date: 2013.07.02 GCF US HOLDINGS LLC

AI summary

The process of making crosslinked cellulose pulp fiber comprising plasma treating a sheet of cellulose pulp fiber before the sheet is impregnated with a crosslinking formulation which comprises a crosslinking agent and a catalyst, then defiberizing the treated cellulose pulp sheet to form treated defiberized cellulose pulp, then heating and curing the treated defiberized cellulose pulp to form intrafiber crosslinked cellulose pulp fibers.