Air-Assisted Contact Nozzle for Elastic Strand Adhesive Coating
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Solution Overview
Problem
Conventional adhesive dispensing systems face challenges in achieving optimal coating characteristics on stretched elastic strands, particularly in balancing creep resistance and force retraction, with non-contact systems experiencing issues with uncontrolled adhesive filaments and contact systems struggling to adequately coat the bottom surface and maintain elasticity.
Innovation Solution
A contact nozzle design that uses pressurized air to spread adhesive along the periphery of stretched elastic strands, ensuring consistent coating and preventing adhesive buildup, while maintaining the elasticity of the strands by varying adhesive thickness, thereby enhancing creep resistance and force retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-contact dispensing systems are used to apply adhesive onto stretched elastic strands, then the adhesive can be dispensed without direct contact, but the adhesive filament becomes uncontrolled and may not adequately wrap around the strand
Solution Approach 1:
A strand guide is introduced as an intermediary component between the adhesive nozzle and the elastic strand. The strand guide positions and supports the elastic strand during adhesive application, providing a reference surface that helps control the adhesive filament's path and ensures adequate wrapping around the strand while maintaining the non-contact dispensing approach
Solution Approach 2:
The patent adjusts operational parameters including adhesive viscosity, dispensing pressure, and nozzle-to-strand distance to optimize filament control. By carefully controlling these parameters, the system achieves sufficient adhesive filament stability and wrap-around capability without requiring direct contact between the nozzle and strand
2Manufacturing precision
If contact dispensing systems are used to apply adhesive onto stretched elastic strands, then the adhesive coating can be controlled, but the bottom surface of the strand is not adequately coated and the strand elasticity is compromised
Solution Approach 1:
The patent transitions from traditional contact dispensing to a non-contact approach with a strand guide, adding a spatial dimension to the adhesive application process. This allows adhesive to be applied from above while the strand guide ensures coverage around the entire periphery including the bottom surface, without compromising strand elasticity through direct nozzle contact
3Strength
If adhesive is applied to ensure high creep resistance, then the bond strength between elastic strands and nonwoven substrates is improved, but the force retraction capability is reduced
Solution Approach 1:
The strand guide enables localized adhesive application around the periphery of the elastic strand, creating different adhesive thickness zones. This results in discrete bond points with high local adhesion strength for creep resistance, while leaving portions of the strand perimeter with lower adhesive presence to maintain elasticity and force retraction capability
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
The contact nozzle system achieves a consistent and optimal adhesive coating along the entire periphery of the strands, improving bonding with nonwoven substrates and maintaining the elasticity and sealing capabilities of hygiene products by ensuring desirable levels of creep resistance and force retraction.
Implementation Method 1
discharge pressurized air towards the adhesive on the strand... causing the adhesive to spread around the periphery of the strand
Data Source
AI summary
A contact nozzle for coating an elastic strand with an adhesive. Air is discharged at the adhesive in contact with the strand, causing the adhesive to spread around the periphery of the strand. The air assists with release of the adhesive from the nozzle and also cleans the nozzle to discourage adhesive build-up on the nozzle.