Absorbent Article Back Ear with Void Region and Mechanical Bond
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Solution Overview
Problem
Current diaper designs face issues with coterminous and non-coterminous elastic back ears, where excessive elastomeric material is unnecessary, leading to increased costs and potential tearing due to inadequate bonding strength, especially when adhesive bonding is used, which can result in weakened nonwoven materials and manufacturing inefficiencies.
Innovation Solution
The design incorporates a back ear with a void region where elastomeric material is absent, joined to the chassis using mechanical bonds that engage the elastomeric material, reducing unnecessary elastomeric material and enhancing bonding strength, thereby improving cost-efficiency and tear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If coterminous elastic back ears are used with elastomeric film extending to the perimeter, then the diaper provides stretch capability and customized fit, but unnecessary elastomeric material is present in locations where elastic properties are not needed, increasing cost
Solution Approach 1:
The elastomeric film is positioned only in specific regions where stretch is needed (outboard of bond sites and engaging member attachment points), while void regions without elastomeric material are created inboard of these locations. This local differentiation provides stretch capability where required while eliminating unnecessary elastomeric material to reduce cost.
2Ease of manufacture
If adhesive bonding is used to join the back ear to the chassis, then the back ear can be attached to the chassis, but the adhesive bond weakens the nonwoven material and reduces tensile strength, especially when adhesive is applied adjacent to the longitudinal edge
Solution Approach 1:
The design extracts or removes the adhesive bonding method from the construction process and replaces it with mechanical bonding. By eliminating adhesive application near the longitudinal edge, the weakening effect on nonwoven material is avoided, preserving tensile strength and reducing the risk of tearing during diaper application.
3Strength
If pressure bonding is used to strengthen the connection between back ear and chassis, then bond strength is increased, but the nonwoven material proximate to bond sites is weakened and prone to tearing under strain
Solution Approach 1:
The elastomeric film serves as an intermediary element that provides mechanical bonding between the back ear and chassis. The mechanical bond engages the elastomeric material directly, distributing forces through the elastic properties of the film rather than concentrating stress on the nonwoven material, thereby maintaining both bond strength and tear resistance.
4Quantity of substance
If non-coterminous back ears are used with void regions, then unnecessary elastomeric material is reduced and cost is decreased, but the bonding strength between back ear and chassis may be insufficient without adequate material overlap
Solution Approach 1:
The elastomeric film acts as a bonding intermediary that compensates for the reduced material overlap in non-coterminous designs. By engaging the elastomeric material directly through mechanical bonding, sufficient bond strength is achieved without requiring extensive overlap of substrates, thus maintaining cost efficiency while ensuring adequate bonding.
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 approach reduces unnecessary elastomeric material costs, strengthens the bond between the back ear and chassis, and minimizes tearing, resulting in a more cost-effective and durable diaper.
Implementation Method 1
Elastomeric films are commonly used since the film provides a degree of stretch to the waist circumference. This stretch allows the diaper to provide a more customized fit. Furthermore, the stretch capability allows the diaper to adjust to the forces exerted by the wearer without causing permanent deformation of the diaper or discomfort for the wearer of the diaper.
Implementation Method 2
The ear is joined to the chassis by at least one mechanical bond that engages the elastomeric material.
Data Source
AI summary
A disposable absorbent article may comprise a chassis and an ear. The chassis comprises a liquid permeable topsheet, a backsheet, and an absorbent core disposed between the topsheet and backsheet. The ear comprises an elastomeric material and a first substrate joined to the elastomeric material. The ear has a first void region adjacent the proximal edge of the ear. The ear is joined to the chassis by at least one mechanical bond that engages the elastomeric material.