Elastic Sheet Joint Hole Geometry for Air Permeability
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Solution Overview
Problem
In disposable wearing articles like diapers, the joint holes tend to close during wear, especially in individuals with a thin body shape, leading to reduced air permeability.
Innovation Solution
An elastic member with an elastic sheet interposed between two sheet layers, where the sheet layers are bonded through joint holes or via sheet joined portions arranged at intervals, with specific geometric relationships between the joined portions to maintain air permeability and prevent excessive closure of joint holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the joint holes are arranged densely to improve bonding strength, then the bonding between sheet layers is strengthened, but the air permeability is reduced
Solution Approach 1:
The patent applies local quality by creating different regions within the elastic member: bonded regions with joined portions for structural support and air permeable regions with joint holes for breathability. This allows each region to optimize its local function without compromising the overall performance.
Solution Approach 2:
The elastic member is segmented into multiple functional zones: sheet layers, elastic sheet, joined portions, and joint holes. This segmentation allows independent optimization of bonding strength and air permeability in different segments, resolving the contradiction between these two requirements.
2Ease of operation
If the elastic sheet is stretched to improve surface fitting, then the flexibility and surface contact are improved, but the joint holes close and air permeability is reduced
Solution Approach 1:
The patent employs dynamics by designing the joint holes to dynamically adjust their opening state based on the stretching level. When the elastic member is stretched, the joint holes naturally open to maintain air permeability, while in the relaxed state they provide bonding. This dynamic behavior resolves the contradiction between surface fitting and air permeability.
Solution Approach 2:
The patent changes the geometric parameters of the joint holes and their arrangement to ensure that during normal stretching, the holes remain open. By carefully designing the hole size, shape, and spacing, the structure maintains air permeability across different stretching states while still providing adequate bonding.
3Stability of the object's composition
If the joined portions are arranged in a grid pattern to improve bonding coverage, then the structural stability is improved, but the air permeability is significantly reduced
Solution Approach 1:
The patent applies partial action by providing bonding only where necessary through strategically placed joined portions, rather than complete coverage. The joint holes are positioned in regions where bonding is less critical, allowing air permeability to be maintained while still providing sufficient structural stability in key areas.
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 ensures adequate air permeability by maintaining the openness of joint holes and reducing contraction force, providing a comfortable fit without excessive tightening.
Implementation Method 1
an elastic sheet stretchable structure in which an elastic sheet is interposed between a first sheet layer and a second sheet layer and the first sheet layer and the second sheet layer are bonded through joint holes penetrating the elastic sheet or via the elastic sheet at a plurality of sheet joined portions arranged at intervals
Data Source
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AI summary
Joint holes are prevented from being excessively closed to lower air permeability. An elastic sheet stretchable structure in which a first sheet layer and a second sheet layer are bonded through joint holes 31 penetrating an elastic film 30 at a plurality of sheet joined portions arranged at intervals is included, joined portion groups 40 and 40 in the stretchable region are in a relationship of intersecting a stretchable direction line ED at respective positions in an orthogonal direction LD or in a relationship of not intersecting the stretchable direction line ED at a separation width of 0.5 mm or less in the orthogonal direction LD of the stretchable direction line ED, and the joined portion groups 40 and 40 are in a relationship of not intersecting an oblique line at a predetermined separation width H in the orthogonal direction in an oblique line group of oblique lines q in the orthogonal direction intersecting the stretchable direction line ED within an angle range γ of 45 degrees or less.