Substrate Bonding With Tackifier-Free Adhesive to Prevent Migration
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Solution Overview
Problem
Existing methods for bonding substrates in absorbent articles using adhesives result in adhesive migration and contamination, leading to aesthetically unpleasing unbonded edges and unintended bonding during assembly operations.
Innovation Solution
Applying a tackifier-free adhesive to one substrate to define an adherence zone, positioning the other substrate on this zone with specific regions bonded and unbonded, and pressing them together to ensure full coverage and penetration, minimizing adhesive exposure and unintended bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied to the discrete waistband before combining with the topsheet, then bonding between the waistband and topsheet is achieved, but adhesive migrates and contaminates material handling equipment
Solution Approach 1:
Instead of applying adhesive to the discrete waistband (which causes migration), the invention inverts the approach by applying adhesive to the continuous topsheet. This reversal prevents contamination of material handling equipment while achieving the same bonding function.
Solution Approach 2:
The invention segments the adhesive application area on the topsheet into discrete patches that correspond to the size and position of the waistband. This segmentation ensures adhesive is only applied where needed, preventing both migration and unbonded edges.
2Object-generated harmful factors
If adhesive is applied in discrete patches on the topsheet to match the waistband size, then adhesive migration is reduced, but very precise placement is required to avoid unbonded edges and exposed adhesive
Solution Approach 1:
The invention applies adhesive with different properties in different locations: discrete patches in areas corresponding to the waistband position, and no adhesive in surrounding areas. This local differentiation reduces the need for precise placement while preventing both migration and unbonded edges.
3Object-generated harmful factors
If adhesive is applied to central portions only of the waistband, then exposed tacky adhesive is reduced, but perimeter edges remain unbonded and loose
Solution Approach 1:
Instead of applying adhesive to the central portion of the waistband (leaving edges unbonded), the invention inverts by applying adhesive to the topsheet in discrete patches that extend to the edges of the waistband area, ensuring complete edge bonding without exposed tacky adhesive.
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 method prevents adhesive migration and unintended bonding, ensuring complete substrate bonding without tacky adhesive exposure, enhancing product quality and assembly efficiency.
Implementation Method 1
applying a tackifier free adhesive to the first surface of the second substrate to define an adherence zone
Implementation Method 2
pressing the first substrate and the second substrate against each other
Data Source
AI summary
The present disclosure relates to methods for bonding first and second substrates together with tackifier free adhesives. The tackifier free adhesive may be applied to the second substrate to define an adherence zone. The first substrate is positioned on the adherence zone of the second substrate to define a first region and a second region of the adherence zone. In the first region, the tackifier free adhesive is positioned between the first substrate and the second substrate. In the second region, the tackifier free adhesive may or may not be positioned between the first substrate and the second substrate, and may not bond the first substrate with the second substrate. Thus, tackifier free adhesive may be applied to the second substrate to create an adherence zone defining a relatively large area that permits the placement of the first substrate thereon without the need to completely cover the adherence zone.