Sulfonated Cellulose Fiber Transparency and Energy Reduction
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Solution Overview
Problem
Existing methods for producing sulfonated cellulose nanofibers face challenges such as high energy requirements, uneven fiber length, and environmental concerns due to the use of strong acids and chlorine-based oxidizing agents, while also lacking clarity on fiber transparency and fibrillation properties.
Innovation Solution
A method involving chemical treatment with a sulfonating agent and urea to introduce sulfo groups into cellulose fibers, followed by fibrillation, which adjusts the sulfur introduction amount and water retention value to achieve sulfonated pulp and fine cellulose fibers with improved transparency and handling properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical fibrillation is performed on cellulose fibers, then cellulose nanofibers are obtained, but high energy consumption is required due to strong hydrogen bonding between fibers
Solution Approach 1:
The patent applies preliminary chemical treatment with sulfonating agents and urea to the cellulose fibers before mechanical fibrillation. This preliminary sulfonation introduces sulfo groups that disrupt hydrogen bonding between fibers, making the subsequent mechanical fibrillation process require significantly less energy while still achieving effective fiber separation and nanofiber production.
2Length of moving object
If mechanical fibrillation is performed to obtain fine nanocellulose, then fiber width is reduced, but fiber length becomes uneven and transparency is insufficient
Solution Approach 1:
The patent changes the chemical parameters of the cellulose fibers by introducing sulfo groups through sulfonation treatment. This chemical modification alters the physical properties of the fibers, enabling them to be fibrillated more uniformly while maintaining consistent fiber length. The sulfo groups reduce inter-fiber bonding strength, allowing for more controlled and uniform mechanical fibrillation that produces nanofibers with both fine width and uniform length, thereby improving transparency.
3Ease of operation
If strong acids or chlorine-based oxidizing agents are used for chemical treatment, then fiber separation is improved, but environmental harm and facility corrosion increase
Solution Approach 1:
The patent converts the traditionally harmful strong acids and chlorine-based oxidizing agents into beneficial sulfonating agents combined with urea. This chemical system achieves effective fiber separation and sulfonation without the severe environmental harm, facility corrosion, and safety issues associated with strong acids and chlorine compounds. The sulfonating agent-urea system provides the necessary chemical modification while being environmentally friendly and easier to handle.
4Manufacturing precision
If chemical treatment with sulfonating agents is performed, then transparency is improved, but control over sulfur introduction amount and water retention is required
Solution Approach 1:
The patent establishes specific parameter ranges for the sulfonation process: sulfur introduction amount of 0.01-2.0 mmol/g and water retention value of 80-200%. By defining these optimal parameter ranges, the patent simplifies process control while achieving the desired transparency. The combination of sulfonating agents with urea and the specified parameter controls enables reproducible production of transparent nanofibers without excessive process complexity.
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 method effectively produces sulfonated pulp and fine cellulose fibers with enhanced transparency, flexibility, and fibrillation efficiency, reducing energy consumption and environmental impact while maintaining fiber length and stability.
Implementation Method 1
a part of the hydroxyl groups of the cellulose fibers of the pulp fiber is substituted with sulfo groups
Implementation Method 2
cellulose fibers are strongly bonded to each other by a hydrogen bond
Implementation Method 3
mechanical fibrillation
Data Source
AI summary
[Object] An object is to provide a sulfonated fine cellulose fiber having excellent transparency, a sulfonated pulp fiber suitable for the sulfonated fine cellulose fiber, a method for producing these fibers, and a derivative pulp containing the sulfonated pulp fiber.[Means for achieving the object] The sulfonated pulp fiber of the present invention is a pulp fiber comprising a plurality of cellulose fibers, wherein a part of hydroxyl groups of the cellulose fibers of the pulp fiber is substituted with sulfo groups, an introduction amount of sulfur attributable to the sulfo groups is adjusted to be higher than 0.42 mmol/g while maintaining a fiber shape, and a water retention value of the pulp fiber is adjusted to 150% or more. Since the sulfonated pulp fiber has a predetermined water retaining property or more while maintaining the fiber shape, the degree of flexibility in handling can be improved.