Absorbent Laminate Structure That Preserves Porosity 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 specific structural features, including a Valley Volume greater than 11 microns and a Pit Density of greater than 25 pockets per square centimeter, is produced using a wet laid structured tissue process, incorporating cellulosic-based and synthetic fibers, and adhered with a water-soluble adhesive, to enhance absorbency and strength.
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 manufacturing ease and production speed are improved, but absorbency is reduced due to web compaction during pressing
Solution Approach 1:
The patent creates a porous web structure by eliminating the pressing step in the manufacturing process. The web is formed on a moving belt and dried without mechanical compression, preserving the natural porosity and void spaces between fibers. This allows the material to maintain high absorbency capability while still being manufacturable using modified conventional processes.
Solution Approach 2:
The patent changes the manufacturing parameters by removing the pressing step and modifying the drying process. Instead of pressing at high pressure to remove water, the web is conveyed through a drying zone that evaporates moisture without compaction. This parameter change maintains web thickness and porosity while achieving the desired moisture removal for product stability.
2Quantity of substance
If more material is used to increase absorbency, then absorbency is improved, but basis weight increases leading to higher cost and reduced environmental sustainability
Solution Approach 1:
By maintaining a porous structure without compaction, the patent maximizes the absorbent capacity per unit mass. The void spaces and surface area available for liquid absorption are preserved, allowing lighter weight materials to achieve the same or better absorbency compared to denser, heavier conventional products.
Solution Approach 2:
The patent uses composite fiber structures combining different fiber types and lengths to optimize absorbency-to-weight ratio. The heterogeneous fiber composition creates a network with enhanced capillary action and liquid retention properties, achieving high absorbency with reduced basis weight.
3Loss of energy
If web pressing is applied to remove moisture efficiently, then energy consumption is reduced, but web thickness and absorbency are lowered
Solution Approach 1:
The patent changes the moisture removal mechanism from mechanical pressing to evaporative drying. The web is conveyed through a controlled drying zone where temperature and air flow parameters are optimized to evaporate moisture without applying compressive force. This preserves web thickness while achieving efficient moisture removal with acceptable energy consumption.
Solution Approach 2:
The patent uses a moving belt conveyance system that incorporates air flow and potentially vacuum assistance to remove excess moisture during formation. This pneumatic approach removes water without mechanical compression, maintaining web bulk and thickness while achieving the desired dewatering effect.
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, reducing the need for costly materials and conserving natural resources, while maintaining strength and performance.
Implementation Method 1
adhered with a water-soluble adhesive
Implementation Method 2
high absorbency of greater than 16 grams of water per gram of fiber
Data Source
AI summary
Absorbent product including a laminate of at least two plies, wherein the absorbent product has a measured Valley Volume parameter greater than 11 microns and a Pit Density of greater than 25 pockets per sq. cm.