Substrate Bonding With Tackifier-Free Adhesive Adherence Zones
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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 potential tearing, as well as unintended bonding during assembly operations due to tacky adhesives.
Innovation Solution
Applying tackifier-free adhesives to define an adherence zone on one substrate, positioning the other substrate to create bonded and unbonded regions, and pressing them together to allow the adhesive to penetrate and intermesh with fibers, thereby ensuring complete bonding without excess tackiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied to discrete waistband prior to combining with topsheet, then bonding between waistband and topsheet is achieved, but adhesive migrates and contaminates material handling equipment
Solution Approach 1:
The patent uses discrete patches of release paper as an intermediary barrier between the adhesive-coated waistband and the material handling equipment. The release paper is positioned on the adhesive application surface, allowing adhesive to be applied without direct contact with equipment, thereby preventing contamination while maintaining bonding effectiveness.
2Object-generated harmful factors
If adhesive is applied in discrete patches to match waistband size, then adhesive contamination is reduced, but precise placement is required to avoid unbonded edges
Solution Approach 1:
The patent applies adhesive to the entire surface of the discrete waistband before any positioning or bonding operations occur. This preliminary adhesive application eliminates the need for precise patch placement during subsequent operations, as the adhesive is already uniformly distributed on the waistband surface, ready for bonding with the topsheet.
3Object-generated harmful factors
If adhesive patches are smaller than waistband size, then contamination is minimized, but perimeter edges remain unbonded and loose
Solution Approach 1:
The release paper acts as a temporary carrier that allows adhesive to be applied to the entire waistband surface without contamination. After bonding, the excess release paper is trimmed away, leaving a clean edge while maintaining complete bonding coverage across the entire waistband perimeter.
4Strength
If adhesive is applied to entire substrate surface, then complete bonding is achieved, but tacky adhesive causes unintended bonding during assembly
Solution Approach 1:
The patent extracts or removes the excess adhesive and unbonded portions along with the discrete patches of release paper after the bonding operation is complete. This extraction eliminates the source of unintended bonding while preserving the intended bond between the waistband and topsheet.
5Object-generated harmful factors
If adhesive is applied to central portions only, then unintended bonding is avoided, but edges become unbonded and aesthetically unpleasing
Solution Approach 1:
The release paper serves as a mask or intermediary that allows adhesive to be applied to the entire surface including edges, while the excess portions are subsequently removed. This process ensures complete edge bonding for aesthetic appearance while preventing unintended bonding during assembly.
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 secure and aesthetically pleasing substrate attachment while minimizing contamination and tearing risks during assembly.
Implementation Method 1
applying a tackifier free adhesive to the first surface of the second substrate to define an adherence zone; positioning the first substrate on the adherence zone of the second substrate
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.