Multi-ply Absorbent Sheet with Fiber-Deprived Cellules
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Solution Overview
Problem
Conventional papermaking processes struggle to produce absorbent products with high water holding capacity and flexibility, as through-air drying methods result in higher water holding capacity but lower tensile strength compared to wet pressing methods, and fabric creping faces challenges in effectively transferring high consistency webs to dryers.
Innovation Solution
A multi-ply absorbent sheet with a fabric-creped web featuring local basis weight variations, including fiber-deprived regions, is created, which exhibits a sponge-like response to sorbed liquid, comprising pileated fiber enriched regions, lower basis weight linking regions, and fiber-deprived cellules, enhancing absorbency and flexibility without the need for through-drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If through-air drying methods are used, then water holding capacity is improved, but tensile strength decreases
Solution Approach 1:
The patent applies local quality by creating a multi-ply structure with distinct functional regions: outer plies provide strength and surface integrity, while the inner core ply provides absorbency through fiber-deprived cellules. This allows different parts of the product to have optimized properties for their specific functions, resolving the contradiction between water holding capacity and tensile strength.
Solution Approach 2:
The patent uses composite materials by combining multiple plies with different fiber compositions and structures. The outer plies use high-basis weight fiber networks for strength, while the core ply uses low-basis weight regions with high void volume for absorbency. This composite approach allows the product to simultaneously achieve high tensile strength and high water holding capacity.
2Strength
If wet pressing methods are used, then tensile strength is improved, but water holding capacity decreases
Solution Approach 1:
The patent segments the product into multiple plies with distinct functions. The outer plies are optimized for strength through wet pressing, while the core ply is optimized for absorbency through a different structure with fiber-deprived cellules. This segmentation allows each segment to excel at its specific function without compromising the other.
Solution Approach 2:
The patent applies local quality by creating a multi-ply structure with distinct functional regions: outer plies provide strength and surface integrity, while the inner core ply provides absorbency through fiber-deprived cellules. This allows different parts of the product to have optimized properties for their specific functions, resolving the contradiction between water holding capacity and tensile strength.
3Productivity
If fabric creping is used to transfer high consistency web, then productivity is improved, but transfer effectiveness deteriorates
Solution Approach 1:
The patent changes the consistency parameter of the web during processing. The outer plies are formed at high consistency for strength, while the core ply is formed at lower consistency to facilitate fabric creping and achieve the desired cellule structure. This parameter change allows effective transfer while maintaining productivity.
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 solution achieves high performance absorbency and flexibility, comparable to through-air dried products, with reduced stiffness and improved wet resilience, while maintaining lower overall weight and energy efficiency, effectively addressing the limitations of conventional methods.
Implementation Method 1
The inventive products exhibit a sponge-like response to sorbed liquid
Implementation Method 2
Conventional wet pressing processes (CWP) have certain advantages over conventional through-air drying processes (TAD) including: (1) lower energy costs associated with the mechanical removal of water rather than transpiration drying with hot air
Implementation Method 3
lower energy costs associated with the mechanical removal of water rather than transpiration drying with hot air
Data Source
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AI summary
A multi-ply absorbent sheet of cellulosic fiber with continuous outer surfaces is provided an absorbent core between the outer surfaces. The absorbent core includes a non-woven fiber network having: (i) a plurality of pileated fiber enriched regions of relatively high local basis weight interconnected by way of (ii) a plurality of lower local basis weight linking regions whose fiber orientation is biased along the direction between pileated regions interconnected thereby, and (iii) a plurality of fiber-deprived cellules between the fiber enriched and linking regions, also being characterized by a local basis weight lower than the fiber enriched regions. The cellules provide a sponge-like internal structure of low fiber density regions.