Buffered Lyocell Fiber Cross-Linking for Fibrillation Stability
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Solution Overview
Problem
Lyocell fibers experience fibrillation and pilling issues due to insufficient protection from cross-linking agents, which decreases over time during storage, especially under varying climatic conditions and pH levels.
Innovation Solution
Incorporating a cross-linking agent that maintains protection from fibrillation by buffering the pH value within a specific range (4.0 to 10.0), using substances like the sodium salt of 2,4-dichloro-6-hydroxy-1,3,5-triazine and buffering agents such as borax, which stabilize the fiber's pH and extend the durability of the cross-linker bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cross-linking agent is used to protect Lyocell fibers from fibrillation, then wet abrasion resistance is improved, but the protection decreases over time during storage due to hydrolysis of cross-linker bonds
Solution Approach 1:
The patent applies parameter changes by controlling the pH environment to stabilize the cross-linker bonds. Specifically, maintaining the fiber in a slightly alkaline pH range (pH 8-10) through the use of buffering agents prevents hydrolysis of the cross-linker bonds, thereby maintaining the protective effect against fibrillation throughout storage. This parameter control transforms the unstable chemical environment into a stable one that preserves the cross-linking agent's functionality.
Solution Approach 2:
The patent introduces buffering agents as intermediary substances that mediate between the cross-linking agent and the storage environment. These buffering agents (such as borax, sodium carbonate, or sodium bicarbonate) create a stable pH environment that protects the cross-linker bonds from hydrolysis. The intermediary buffering system thus shields the cross-linking agent from the harmful effects of pH variations during storage.
2Adaptability or versatility
If the fiber is stored under varying climatic conditions, then adaptability to different environments is improved, but the stability of protection from fibrillation decreases
Solution Approach 1:
The patent employs parameter changes by establishing a buffer zone in the pH range of 8-10 that remains stable across varying climatic conditions. The buffering agents maintain this pH parameter even when exposed to different temperatures and humidity levels during storage, thereby preserving the stability of cross-linker bonds while allowing the fiber to adapt to various environmental conditions.
Solution Approach 2:
The patent applies beforehand cushioning by pre-establishing a stable pH environment through buffering agents before the fiber is subjected to varying climatic conditions during storage. This prior cushioning in the form of a buffered pH system protects the cross-linker bonds from the destabilizing effects of environmental variations, ensuring long-term stability of the fibrillation protection.
3Adaptability or versatility
If the pH value changes during storage, then the fiber's response to environmental conditions is improved, but the protection from fibrillation decreases due to hydrolysis
Solution Approach 1:
The patent applies parameter changes by deliberately controlling and stabilizing the pH parameter within the optimal range of 8-10 using buffering agents. This controlled parameter change ensures that the fiber maintains its protective properties against fibrillation while being able to respond appropriately to environmental conditions. The buffering system prevents pH from dropping into ranges that would cause hydrolysis, thus maintaining both adaptability and reliability.
Solution Approach 2:
The patent introduces buffering agents as intermediary substances that mediate between pH changes and the cross-linker bonds. These intermediaries absorb or release protons to maintain a stable pH environment, preventing direct exposure of the cross-linker bonds to pH variations that would cause hydrolysis. This intermediary buffering system thus preserves the durability of protection while allowing controlled pH responsiveness.
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 buffering mechanism effectively maintains the protection from fibrillation over an extended period, reducing the degradation of wet abrasion resistance by up to 20% within the optimal pH range, thereby enhancing the storage stability of Lyocell fibers.
Implementation Method 1
the fiber contains a substance buffering in the range from 7.0 to 11.0 and exhibits a buffer capacity of at least 12 mmol/kg fiber
Implementation Method 2
the treatment of a Lyocell fiber with a cross-linking agent constitutes a commercially significant approach
Implementation Method 3
this is due to a slow, but continuous hydrolysis of the cross-linker bonds
Data Source
AI summary
The invention concerns a cellulose fiber of the genus Lyocell which is treated with a cross-linking agent, with the cross-linking agent inducing a protection from fibrillation on the fiber and exhibiting the following properties:the protection from fibrillation induced by the cross-linking agent changes if the fiber is stored within a pH range from 4.0 to 10.0, in particular under the influence of moisture and/or heat,within the pH range from 4.0 to 10.0, an optimum value exists at which the stability of the protection from fibrillation induced by the cross-linking agent during storage is highesta suitable range exists around the optimum value in which the stability is reduced by 20% at the most, compared to the stability at the optimum value,within the pH range from 4.0 to 10.0, the suitable range is limited by at least one limiting value at which the stability is reduced by 20% compared to the long-term stability at the optimum value and with a further decrease in stability occurring below and above said value, respectively, andthe cross-linking agent has the capability to change the pH value.The fiber according to the invention is characterized in that the fiber comprises a buffering substance in the suitable range and exhibits a buffer capacity of at least about 12 mmol/kg fiber, preferably from about 15 to about 70 mmol/kg fiber, in the suitable range.