Multi-Ply Absorbent Laminate for High Uptake at Low Basis Weight
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Solution Overview
Problem
Existing 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 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 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, non-compacted web structure by using an air-laid process instead of conventional water-laid pressing methods. The web is formed by depositing fibers onto a moving belt through an air stream, creating a three-dimensional structure with high void volume that maintains absorbency without requiring intensive pressing that would compact the material and reduce pore space.
Solution Approach 2:
The patent changes the fundamental processing parameters by switching from water-laid to air-laid technology. This involves changing the fiber deposition mechanism from water-based slurry to air-stream transport, and changing the dewatering method from mechanical pressing to thermal drying, thereby preserving web porosity and absorbency while maintaining manufacturability.
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 creating a highly porous web structure through air-laid technology, the patent increases the void volume and surface area available for liquid absorption without adding more fiber material. The three-dimensional fiber arrangement creates more absorption pathways and capillary action sites, achieving higher absorbency per unit weight.
Solution Approach 2:
The patent transitions from a two-dimensional compacted web to a three-dimensional porous structure. The air-laid process allows fibers to arrange in a volumetric configuration with varying densities throughout the web thickness, creating multiple absorption zones that enhance overall absorbency without increasing basis weight.
3Use of energy by stationary object
If web pressing is applied to remove moisture during manufacturing, then energy consumption is reduced, but web thickness and resulting absorbency are lowered
Solution Approach 1:
The patent changes the moisture removal parameter from mechanical pressing to thermal drying. By using an air-laid process with thermal drying, the web can be dried to the desired moisture content without the compaction forces that would reduce web thickness and absorbency, maintaining a balance between energy efficiency and structural integrity.
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, effectively conserving costly fibrous materials and improving environmental sustainability.
Implementation Method 1
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
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.