Nested Embossed Multi-Ply Sheet for Rapid Absorption
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Solution Overview
Problem
Existing embossed multi-ply sheets of creped cellulose wadding for sanitary or domestic use, such as paper towels, face challenges in enhancing absorption capacity without compromising mechanical characteristics or visual appeal, and in improving flexibility for user satisfaction.
Innovation Solution
A sheet composed of at least two plies of creped cellulose wadding with specific embossing patterns where the first ply features aligned frustoconical protrusions with vertices oriented inward, and the second ply has higher protuberances that nest into the first ply's protrusions, creating voids for rapid liquid absorption, while maintaining mechanical strength and visual attractiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional nested or point/point embossing patterns are used, then the sheet achieves homogeneous mechanical characteristics, but the flexibility and user satisfaction are reduced
Solution Approach 1:
The patent applies asymmetry by using two different embossing patterns: a first pattern with aligned frustoconical protrusions for mechanical strength, and a second pattern with random or semi-random distributed protrusions for flexibility. This asymmetric combination resolves the contradiction between mechanical homogeneity and flexibility by assigning different functions to different regions of the multi-ply sheet.
Solution Approach 2:
The patent implements local quality by giving different embossing characteristics to different plies: the first ply has a regular embossing pattern optimized for tensile strength, while the second ply has an irregular pattern optimized for flexibility and comfort. Each region (ply) is locally optimized for its specific function, resolving the contradiction between overall mechanical stability and local flexibility.
2Quantity of substance
If multiple plies are combined to increase absorption capacity, then the absorption improves, but the mechanical characteristics such as tensile strength may be compromised
Solution Approach 1:
The patent applies nesting by placing the second ply with its protrusions inside the recesses formed by the first ply's protrusions. This nested arrangement creates interlocking points that mechanically bond the plies together, maintaining tensile strength while the combined multi-ply structure provides increased absorption capacity through additive effect of multiple absorbent layers.
Solution Approach 2:
The patent combines multiple plies with different embossing patterns and properties into a single multi-ply sheet. By merging the first ply (optimized for strength) and second ply (optimized for absorption and flexibility), the final product achieves both high tensile strength and high absorption capacity simultaneously, resolving the contradiction between these two properties.
3Strength
If the sheet is made with high density and uniform structure, then mechanical strength is improved, but the liquid absorption rate decreases
Solution Approach 1:
The patent creates porous structures through embossing that form voids and channels between the protrusions of the two plies. These porous regions, particularly in the second ply with its random pattern, provide rapid liquid absorption pathways while the overall structured embossing pattern maintains mechanical integrity. The porous architecture resolves the contradiction between strength and absorption speed.
Solution Approach 2:
The patent segments the sheet into multiple plies with different functions: the first ply provides mechanical strength through its regular embossing pattern, while the second ply provides rapid absorption through its porous, random-pattern structure. This segmentation allows each ply to be optimized for its specific function, resolving the contradiction between overall strength and absorption rate.
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 proposed design significantly enhances liquid absorption rate without reducing mechanical characteristics, making the sheet more pleasant to use and visually appealing, with improved flexibility and absorption performance compared to prior art.
Implementation Method 1
the lower protuberances of the second ply are arranged between the protuberances of the first ply so as to create between the two folds of the empty spaces promoting rapid absorption of liquid
Data Source
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AI summary
The invention provides an embossed sheet composed of at least a first and a second ply of creped cellulose wadding having a basis weight between 12 and 30 g/m2 according to which the first ply (4) has a first embossed pattern composed of a series of first aligned protrusions (20) of frustoconical overall shape, the tops of which are oriented towards the inside of the sheet, the second ply (2) comprises a first and a second series of protrusions, the tops of which are oriented towards the inside of the sheet, the first series (5) having a height greater than that of the second series of protrusions (3). According to the invention, the protrusions (20) of the first ply (4) and the highest protrusions (5) of the second ply (2) are nested inside one another, and the lowest protrusions (3) of the second ply (2) are arranged between the protrusions of the first ply so as to create empty spaces (6) between the two plies that promote a rapid absorption of liquid. The invention furthermore relates to a pair of rolls and to the associated process for producing such embossed sheets.