Backsheet Arrangement Leg Elastic Anchoring
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Solution Overview
Problem
Existing disposable absorbent articles with side flaps face design restrictions due to the need for bond-free snap-back channels for leg elastic elements, which can weaken the material and interfere with side flap attachment, limiting the freedom in designing the width of the absorbent core and topsheet/backsheet.
Innovation Solution
The absorbent article features a backsheet arrangement with leg elastic anchoring portions formed by two layers of backsheet material, where leg elastic members are fully or partly arranged laterally outward of flap anchoring areas, allowing for snap-back without direct contact with the topsheet, eliminating the need for bond-free snap-back channels and enabling flexible placement of leg elastic elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leg elastic elements are arranged with bond-free snap-back channels between topsheet and backsheet, then snap-back function is achieved, but material strength is reduced and side flap attachment is interfered with
Solution Approach 1:
The patent moves the snap-back channel from the plane between topsheet and backsheet to the longitudinal direction within the backsheet layer itself. The U-shaped cut creates a three-dimensional snap-back path that eliminates the need for bond-free channels in the topsheet-backsheet interface, thereby maintaining material strength while achieving snap-back function.
Solution Approach 2:
The patent extracts the snap-back function from the bond-free channel concept and implements it through U-shaped cuts in the backsheet. This separates the snap-back mechanism from the adhesive bonding areas, allowing full adhesive coverage between topsheet and backsheet without compromising elastic element retraction.
2Reliability
If leg elastic elements are placed laterally inward to accommodate snap-back channels, then snap-back is adequate, but design freedom for absorbent core and topsheet width is restricted
Solution Approach 1:
The patent relocates the snap-back mechanism from lateral displacement (requiring inward placement) to longitudinal displacement within the backsheet layer. The U-shaped cut allows elastic elements to snap back along the length of the backsheet rather than requiring lateral space, enabling flexible positioning and optimal sizing of the absorbent core and topsheet.
3Reliability
If topsheet and backsheet are made wider to accommodate both snap-back areas and side flap anchoring areas, then both functions are satisfied, but article width is increased beyond functional requirements
Solution Approach 1:
The patent extracts the snap-back mechanism from the lateral space requirement and embeds it within the backsheet structure through U-shaped cuts. This eliminates the need for additional lateral width to accommodate snap-back channels, allowing the topsheet and backsheet to be sized precisely according to functional requirements without excess material.
4Strength
If adhesive is applied extensively between topsheet and backsheet, then attachment strength is improved, but snap-back function is compromised due to restricted elastic element movement
Solution Approach 1:
The patent segments the backsheet structure by introducing U-shaped cuts that create distinct adhesive bonding areas and snap-back channels. Adhesive can be applied extensively in the bonding areas between topsheet and backsheet while the U-shaped cut regions remain free of adhesive, providing dedicated pathways for elastic element retraction without compromising overall attachment strength.
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
This solution allows for independent placement of leg elastic elements without interfering with side flap attachment, eliminating weakened areas and providing freedom in designing the absorbent article's width to meet functional requirements, enhancing fit and absorbency while preventing material rupture under tensile stress.
Implementation Method 1
continuous leg elastic elements are stretched and fed along with the traveling webs and are intermittently attached in their stretched state
Data Source
Figure 1~2
Figure 3
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AI summary
An absorbent article (1) having first and second waist edges (2,4) and first and second side edges (6,8), the absorbent article (1) comprising a topsheet (9), a backsheet arrangement (10), an absorbent member (11) being disposed between the topsheet (9) and the backsheet arrangement (10), a first side flap (12) extending from the first side edge (6) of the absorbent article (1) and a second side flap (13) extending from the second side edge (8) of the absorbent article (1) the first and second side flaps (12, 13) being attachment flaps, and first and second leg elastic members (18, 19) extending along first and second side edges (20, 21) of the backsheet arrangement (10). The first and second side flaps (13) are secured between the topsheet (9) and the backsheet arrangement (10) within first and second flap anchoring areas (22, 23) being arranged at the first waist edge (2). The backsheet arrangement (10) comprises first and second leg elastic anchoring portions (30, 31) extending along the side edges (6, 8) of the absorbent article (1), the first and second leg elastic anchoring portions (30, 31) comprising two layers of backsheet material (32, 33), the first and second leg elastic members (18, 19) being arranged between the two layers of backsheet material (32, 33), each leg elastic anchoring portion (30, 31) being fully or partly arranged laterally outward of an inner edge (25) of a corresponding flap anchoring area (22, 23), the first and second leg elastic members (18, 19) terminating at a distance from the first waist edge (2), whereby first leg elastic free portions (35, 36) are arranged at the first waist edge (2).