Crosslinked Cellulosic Fibers for Safer High-Absorbency Structures
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Solution Overview
Problem
Current cellulosic fibers cross-linked with existing agents, such as formaldehyde and C2-C9 polycarboxylic acids, face challenges including safety concerns, high costs, and inadequate absorbency benefits, limiting their commercial success in absorbent products.
Innovation Solution
Development of cellulosic fibers cross-linked with a phosphinate-containing telomer of acrylic acid, which exhibits improved penetration and mobility within the fiber structure, enhancing wet and dry resilience and absorbency properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cross-linking agents (formaldehyde, C2-C9 polycarboxylic acids) are used, then cross-linking is achieved, but safety concerns and high costs limit commercial success
Solution Approach 1:
The patent changes the chemical parameters of the cross-linking agent by using phosphinate-containing telomers of acrylic acid with specific molecular weight ranges (500-5000) and controlled architecture. This substitution provides safe, effective cross-linking without the hazards of formaldehyde or the high costs of conventional polycarboxylic acids, resolving the contradiction between safety and commercial feasibility.
2Reliability
If cross-linking agents are used that provide adequate penetration, then cross-linking occurs, but absorbency benefits are insufficient
Solution Approach 1:
The patent applies local quality by designing cross-linked regions within individual fibers while maintaining uncross-linked regions for absorbency. The controlled cross-linking density and specific fiber structure create zones of different properties: cross-linked zones provide structural integrity while uncross-linked zones maintain fluid absorption capability, resolving the contradiction between reliable cross-linking and sufficient absorbency benefit.
3Stability of the object's composition
If cross-linking is performed in unswollen fiber state, then intrafiber cross-links are formed, but fluid retention values are low
Solution Approach 1:
The patent applies dynamics by controlling the fiber swelling state during cross-linking. Fibers are swollen during cross-linking agent penetration to allow thorough distribution, then cross-linked in a controlled manner. This dynamic control of fiber state during processing enables both adequate intrafiber cross-links and sufficient fluid retention capacity.
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 phosphinate-containing telomers of acrylic acid provide higher absorbency and resilience in absorbent structures, overcoming the limitations of previous cross-linking agents while being safe for human skin and commercially feasible.
Implementation Method 1
the cross-linking agent penetrates and distributes thoroughly within the interior of the individual fiber structure prior to cross-linking or during the cross-linking process
Implementation Method 2
cellulosic fibers having intrafiber cross-links formed with a phosphinate-containing telomer of acrylic acid
Data Source
AI summary
This invention relates to cellulosic fibers with high fluid absorption properties, and absorbent articles made from such cellulosic fibers, and processes for making such fibers and structures. More specifically, this invention relates to intra-crosslinked cellulosic fibers with phosphinate-containing telomers of acrylic acid and absorbent structures containing such fibers.