Absorbent Article Stretchable Structure Pleat Control
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Solution Overview
Problem
The existing stretchable structures in absorbent articles face issues with pleat deformation and appearance deterioration due to unintended adhesion of hot melt adhesive, leading to irregularities and loss of flexibility.
Innovation Solution
The use of a combination of spunbond nonwoven fabric and air-through nonwoven fabric with a specific hot melt adhesive application pattern, where the air-through nonwoven fabric's fluffy surface with poor adhesiveness and the spunbond nonwoven fabric's high adhesiveness prevent unintended adhesion, ensuring reliable bonding and maintaining pleat appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If hot melt adhesive is applied in a striped pattern intermittent in the longitudinal direction of elastically stretchable members and continuously elongated in the direction intersecting with the elastically stretchable members, then the pleats can extend straightly along the sheet bonded portions with excellent appearance, but it is extremely difficult to stably apply the adhesive and stringiness or scattering occurs causing unintended adhesion that collapses or irregularly deforms the pleats
Solution Approach 1:
The patent applies different nonwoven fabric types to different locations: air-through nonwoven fabric is used on the outer surface where pleat appearance is critical, while spunbond nonwoven fabric is used on the inner surface where adhesive bonding is required. This local differentiation allows the adhesive to be applied continuously for manufacturing efficiency while the air-through fabric's low adhesiveness prevents unintended bonding that would deform pleats, thus resolving the contradiction between pleat appearance and adhesive application precision.
2Reliability
If hot melt adhesive is applied continuously in the direction intersecting with elastically stretchable members, then bonding reliability is improved, but stringiness and scattering of adhesive cause unintended adhesion at portions supposed to be non-adhesive
Solution Approach 1:
The patent creates a local quality difference by using air-through nonwoven fabric on the outer surface which has inherently low adhesiveness to hot melt adhesive. This allows the adhesive to be applied continuously for reliable bonding at intended locations, while the air-through fabric's properties prevent unintended adhesion even when adhesive stringiness or scattering occurs, thus resolving the contradiction between bonding reliability and unintended adhesion.
Solution Approach 2:
The patent converts the potential harm of adhesive stringiness and scattering into a benefit by using air-through nonwoven fabric whose low adhesiveness prevents unintended bonding. What would normally be a manufacturing defect (adhesive scattering) becomes acceptable because the air-through fabric's properties prevent harmful unintended adhesion, thus converting the harmful factor into a tolerable condition.
3Object-generated harmful factors
If air-through nonwoven fabric is used to prevent unintended adhesion, then pleat appearance is maintained, but bonding strength may be insufficient
Solution Approach 1:
The patent uses air-through nonwoven fabric only on the outer surface where pleat appearance is critical and unintended adhesion must be prevented, while using spunbond nonwoven fabric on the inner surface where strong bonding is required. This spatial differentiation allows each material to perform its optimal function: air-through fabric prevents unintended adhesion and maintains appearance, while spunbond fabric provides strong bonding strength.
Solution Approach 2:
The patent creates a composite structure by laminating two different nonwoven fabrics (air-through and spunbond) with different properties. The air-through nonwoven fabric layer provides low adhesiveness to prevent unintended bonding and maintain pleat appearance, while the spunbond nonwoven fabric layer provides high adhesiveness for reliable bonding strength, thus combining the benefits of both materials to resolve the contradiction between preventing unintended adhesion and ensuring bonding 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 effectively prevents pleat deformation and maintains the appearance by ensuring that the hot melt adhesive does not unintentionally bond the sheet layers, even under conditions of stringiness or scattering, while providing sufficient adhesion for forming well-defined pleats.
Implementation Method 1
The first sheet layer and the second sheet layer are bonded via a hot melt adhesive disposed in a striped pattern
Implementation Method 2
with contraction of the elastically stretchable members, portions positioned between sheet bonded portions of the first sheet layer and the second sheet layer contract and are raised in the opposite directions from each other to form pleats
Data Source
AI summary
A stretchable structure of an absorbent article has a first sheet layer of a nonwoven fabric; a second sheet layer of a nonwoven fabric and opposed to one side of the first sheet layer. A plurality of elongated elastically stretchable members are provided along the stretchable direction at intervals from each other between the first sheet layer and the second sheet layer. The first sheet layer and the second sheet layer have sheet bonded portions bonded via a hot melt adhesive disposed in a striped pattern that is intermittent in the longitudinal direction of the elastically stretchable members and continuously elongated in the direction intersecting with the elastically stretchable members. One of the first sheet layer and the second sheet layer is a spunbond nonwoven fabric, and the other sheet layer is an air-through nonwoven fabric whose surface on the spunbond nonwoven fabric side is a fluffy surface.