Multi-Ply Absorbent Towel Structure for High Absorbency at Low Basis Weight
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Solution Overview
Problem
Current absorbent structures, such as disposable paper towels and wipes, face challenges in achieving high absorbency while maintaining low basis weight, which is essential for cost-effectiveness and environmental sustainability.
Innovation Solution
A laminate of at least two plies with a Valley Volume greater than 11 microns and a Pit Density of greater than 25, produced using a wet laid structured tissue process, where each ply comprises cellulosic-based or synthetic fibers, and the plies are embossed and adhered together with a water-soluble adhesive, enhancing absorbency without increasing basis weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional water-laid or air-laid technologies are used to produce absorbent structures, then production efficiency and ease of manufacture are improved, but the basis weight increases and absorbency is compromised due to web compaction
Solution Approach 1:
The patent employs a porous forming fabric with a three-dimensional structure comprising raised areas and recessed areas. The recessed areas create void spaces that prevent web compaction during the dewatering process, maintaining high porosity and low basis weight while enabling efficient water drainage. This porous structure allows the web to retain its thickness and absorbency without requiring excessive material.
Solution Approach 2:
The invention transitions from conventional two-dimensional flat web formation to three-dimensional structured web formation using a porous fabric with raised and recessed areas. This dimensional change creates a non-uniform web structure with varying thickness zones, allowing the web to maintain bulk and absorbency while reducing overall material consumption and basis weight.
2Use of energy by moving object
If sheet pressing is applied to remove moisture during production, then energy consumption is reduced, but web thickness and resulting absorbency are lowered
Solution Approach 1:
The porous forming fabric enables mechanical dewatering through its permeable structure, allowing water to drain through the recessed areas without applying excessive pressing force. This natural drainage mechanism reduces the need for high-energy pressing operations while maintaining web thickness, as the fabric's porosity facilitates water removal without compacting the web structure.
Solution Approach 2:
The invention utilizes hydraulic principles where water is removed from the web through the porous fabric's permeable structure during the forming process. The fabric's capillary action and pressure gradient facilitate water drainage through the recessed areas, enabling efficient moisture removal without mechanical compression that would reduce web thickness and absorbency.
3Reliability
If more material is used to enhance strength and absorbency, then product performance is improved, but cost and environmental impact increase
Solution Approach 1:
The porous forming fabric creates localized zones of varying web structure with raised areas providing strength and recessed areas providing absorbency. This local quality differentiation allows different regions of the web to perform different functions, optimizing overall product performance while minimizing total material consumption by placing material only where structurally necessary.
Solution Approach 2:
The invention creates a composite web structure formed on the porous fabric, combining cellulosic fibers with the fabric's three-dimensional architecture. This composite structure integrates the strength-providing fiber network with the porosity-providing fabric framework, achieving both mechanical strength and high absorbency without requiring excessive amounts of either component.
4Productivity
If conventional creping processes are used, then production speed is maintained, but web bulk and surface topography are compromised
Solution Approach 1:
The porous forming fabric maintains its three-dimensional structure throughout the creping process, preventing web compaction even at high production speeds. The fabric's permeable structure allows steam and air to penetrate during drying and creping, maintaining web bulk and porosity without requiring reduced production speed. The raised and recessed areas of the fabric preserve web thickness during the mechanical actions of creping.
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 absorbency of greater than 16 grams of water per gram of fiber at a basis weight of less than 43 grams per square meter, conserving natural resources and reducing production costs while maintaining product effectiveness.
Implementation Method 1
nearly half of the water removed from the web is through drainage and mechanical pressing
Implementation Method 2
transferred to a dewatering felt where it is pressed to remove moisture
Implementation Method 3
The web is then dried and creped from the Yankee Dryer
Data Source
AI summary
A through-air-dried disposable retail towel product including a laminate of at least two multi-layer plies, wherein the product has a measured Valley Volume parameter of 18 to 25 microns and a Pit Density of 16 to 25 pockets per sq. cm.