Surface-Enhanced Pulp Fibers for High Absorbency and Strength
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Solution Overview
Problem
Conventional pulp fiber refining processes reduce fiber length and increase fines, leading to decreased absorbency and strength in paper products, while also requiring excessive refining energy.
Innovation Solution
The use of surface-enhanced pulp fibers (SEPF) with increased length and hydrodynamic specific surface area, combined with softwood fibers, to create paper products with improved absorbency and strength, allowing for reduced refining energy and lower freeness without compromising product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional refining processes are used to increase fibrillation, then bonding and strength are improved, but fiber length is reduced and absorbency decreases
Solution Approach 1:
The patent applies parameter changes by modifying the refining process parameters, specifically using high energy input (450-600 kWh/ton) to achieve surface enhancement of pulp fibers. This transforms the physical and chemical parameters of the fiber surface, increasing hydrodynamic specific surface area and creating a fibrillar network that improves bonding without the same detrimental effects as conventional refining
Solution Approach 2:
The patent creates a composite structure on the fiber surface by forming a fibrillar network that combines with the original fiber structure. This composite morphology provides both the bonding capability of refined fibers and maintains the structural integrity and length of the original fibers, thereby preserving absorbency
2Strength
If conventional refining processes are used to increase fibrillation, then bonding is improved, but absorbency decreases due to reduced pore size
Solution Approach 1:
The patent changes the refining parameters to use extremely high energy input (450-600 kWh/ton), which creates surface enhancement rather than bulk fiber degradation. This parameter change produces a fibrillar network on the fiber surface that increases bonding area while preserving the macroscopic pore structure necessary for absorbency
Solution Approach 2:
The patent applies local quality by concentrating the refining effect on the fiber surface rather than throughout the entire fiber. The surface-enhanced pulp fibers have modified surface properties (increased hydrodynamic specific surface area) while the core fiber structure and surrounding pore network remain intact, enabling localized bonding enhancement without global absorbency loss
3Stability of the object's composition
If conventional refining processes are used, then fibrillation is increased, but excessive refining energy is required
Solution Approach 1:
The patent fundamentally changes the refining parameters by applying extremely high energy density (450-600 kWh/ton), which shifts the refining mechanism from gradual mechanical wear to intense surface fibrillation. This parameter change achieves superior fibrillation and surface enhancement more efficiently than conventional multi-pass refining at lower energy levels
4Stability of the object's composition
If conventional refining processes are used, then fibrillation is increased, but fiber length is significantly reduced
Solution Approach 1:
The patent changes the energy input parameter to extremely high levels (450-600 kWh/ton), which alters the refining mechanism to preferentially fibrillate the fiber surface rather than mechanically fragmenting the fiber. This parameter change decouples fibrillation from fiber length reduction, achieving both goals simultaneously
Solution Approach 2:
The patent applies preliminary action by performing surface enhancement refining before paper formation. This preliminary surface modification creates a fibrillar network on the fibers that will provide bonding capability during papermaking, eliminating the need for subsequent heavy refining that would further reduce fiber length
Data Source
AI summary
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.