Laminated Absorbent Structures with High Strength and Low MD Stretch
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Solution Overview
Problem
Existing absorbent structures, such as disposable paper towels and wipes, face challenges in achieving high absorbency, strength, and softness while minimizing machine direction (MD) stretch, which affects productivity and cost efficiency.
Innovation Solution
The use of a structuring fabric on a TAD asset to laminate absorbent structures with specific parameters, including a Y-Connected Area greater than 20 and Surface Channel Spacing less than 2.5 mm, and embossing the plies with a water-soluble adhesive, results in high ball burst strength, absorbency, and softness at low MD stretch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional water-laid or air-laid technologies are used to produce absorbent structures, then the structures can be manufactured with basic absorbency, but they fail to achieve high strength and high softness simultaneously while maintaining low machine direction stretch
Solution Approach 1:
The patent applies Through Air Drying (TAD) technology which fundamentally changes the drying parameter from conventional water-laid methods. The TAD process uses hot air circulation to dry the web at lower temperatures without mechanical compression, achieving high strength while maintaining low MD stretch and high softness simultaneously
Solution Approach 2:
The patent uses laminated multi-ply structures where multiple layers are bonded together. This composite approach enhances overall strength and absorbency while the specific lamination configuration helps control stretch characteristics in the machine direction
2Use of energy by stationary object
If sheet pressing is applied to remove moisture from the web, then energy consumption is reduced, but the web thickness and resulting absorbency are lowered
Solution Approach 1:
The drying process is segmented into multiple zones within the TAD chamber, allowing different regions of the web to be dried at different rates and temperatures. This prevents excessive compression while still achieving thorough moisture removal, maintaining web thickness and absorbency
Solution Approach 2:
The TAD process uses pneumatic circulation of hot air throughout the drying chamber instead of mechanical pressing. This pneumatic approach removes moisture through evaporation and air flow rather than compression, preserving web thickness while consuming reasonable energy
3Strength
If more than one layer of web is laminated together to enhance strength and absorbency, then product performance improves, but MD stretch increases affecting productivity
Solution Approach 1:
The lamination process is designed to create localized bonding zones rather than uniform bonding across the entire web. This selective lamination enhances strength where needed while leaving other areas more flexible, thereby reducing overall MD stretch and improving 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 unprecedented levels of absorbency, strength, and softness with minimal MD stretch, enhancing productivity and reducing costs by eliminating the need for speed differentials and chemical additives.
Implementation Method 1
laminate absorbent structures with specific parameters, including a Y-Connected Area greater than 20 and Surface Channel Spacing less than 2.5 mm, and embossing the plies with a water-soluble adhesive
Implementation Method 2
Absorbent structures can be produced using both Water or Air-Laid technologies... These disposable absorbent towels and wipes are used for a multitude of tasks that require absorbency
Data Source
AI summary
Absorbent product including a laminate of at least two plies, wherein the absorbent product has a measured Y-Connected Area parameter greater than 20 and a Surface Channel Spacing of less than 2.5 mm. The absorbent product has high strength and low machine direction stretch.