Disposable Diaper Waist Edge Intermittent Joining for Pleat Control
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Solution Overview
Problem
Conventional underpants-type disposable diapers face issues with air permeability and wearing comfort due to pleats that are either fluffy or wavy, leading to inferior appearance and rigidity at the waist edge portion.
Innovation Solution
The diaper employs a vertical continuous joined form with a wide area not having resilient and elastic members at the waist edge portion, where the inner and outer layers are intermittently joined with adhesive or welding, allowing for pleats that extend straight and provide excellent softness and air permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the inner and outer layers are intermittently joined with adhesive or welding to form sheet joined sections, then air permeability and softness are improved, but the resilient and elastic members may not be securely fixed
Solution Approach 1:
The joining is performed intermittently in the width direction rather than continuously, creating discrete sheet joined sections. This segmentation allows air to pass through the unjoined portions while still providing sufficient fixing points for the resilient and elastic members, resolving the contradiction between air permeability and fixing reliability.
Solution Approach 2:
The adhesive or welding is applied locally at specific sections rather than uniformly across the entire width. This creates zones of different properties: joined sections provide fixing reliability while unjoined sections maintain air permeability and softness, allowing each local area to optimize its function.
2Adaptability or versatility
If resilient and elastic members are arranged close to the edge of waist opening, then fit to human body is improved, but hard sheet joined sections form vertically continuous grooves causing rigidity and poor wearing feeling
Solution Approach 1:
The sheet joined sections are positioned at specific locations that are not vertically continuous at the waist opening edge. This creates local variations in rigidity: the resilient and elastic members can be arranged close to the edge for good fit, while the joining pattern prevents continuous rigid grooves from forming, maintaining comfort at the sensitive waist opening area.
Solution Approach 2:
The joining is segmented in the width direction with gaps between sheet joined sections. This segmentation prevents the formation of vertically continuous rigid grooves even when resilient and elastic members are close to the edge, allowing the structure to maintain both fit and comfort.
3Strength
If hot-melt adhesive is applied like a sheet to join outer layer and inner layer, then fixing strength is improved, but cost increases and flexibility decreases
Solution Approach 1:
Instead of applying hot-melt adhesive as a continuous sheet, the adhesive is applied intermittently in discrete sections. This segmentation significantly reduces the amount of adhesive required, lowering material costs while still providing sufficient fixing strength at the critical joining points.
Solution Approach 2:
The adhesive is applied partially rather than fully across the entire surface. This partial action provides just enough fixing strength for the application while avoiding the excess adhesive that would increase cost and reduce flexibility, achieving the optimal balance between strength and flexibility.
4Ease of manufacture
If hot-melt adhesive is applied to peripheral surface to reduce amount used, then cost is reduced, but flexibility may be compromised
Solution Approach 1:
The adhesive application is segmented into discrete sections along the peripheral surface rather than continuous coverage. This segmentation reduces the total amount of adhesive used, lowering cost, while the segmented pattern itself maintains flexibility by not creating a continuous rigid bond that would restrict movement.
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 design results in a diaper with improved air permeability and wearing comfort, featuring large, sparse, and flexible contraction wrinkles at the waist edge, enhancing both appearance and user experience.
Implementation Method 1
the inner layer and the outer layer are joined by an adhesive arranged intermittently or a welding process performed intermittently in the width direction
Implementation Method 2
the inner layer and the outer layer are joined by an adhesive arranged intermittently or a welding process performed intermittently in the width direction
Implementation Method 3
the waist edge portion resilient and elastic members are fixed to at least one of the inner layer and the outer layer, the inner layer and the outer layer contracting as the waist edge portion resilient and elastic members contract
Data Source
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AI summary
In an underpants-type disposable diaper including a waist edge portion in which pleats extend straight and which has excellent fit, the inner layer (21) and the outer layer (22) at the waist edge portion (W) of an outer body (12) are joined by an adhesive (71) arranged intermittently or a welding process performed intermittently in the width direction and continuously in a direction crossing the width direction, thereby forming sheet joined sections (70), waist edge portion resilient and elastic members (17) are sandwiched between the inner layer (21) and the outer layer (22) and fixed to at least one of the inner layer (21) and the outer layer (22) at positions intersecting with the sheet joined sections (70), and the diaper includes an area (25) not being joined and not having resilient and elastic member at an end portion of the outer body (12) on the waist opening (WO) side in the waist edge portion (W), the area not having sheet joined sections (70) nor the waist edge portion resilient and elastic members (17), and a vertical range being wider than spacing between the waist edge portion resilient and elastic member (17) positioned closest to the waist opening (WO) side, and the waist edge portion resilient and elastic member (17) adjacent thereto.