Elastomeric Polypropylene Yarn Mechanical Bonding
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Solution Overview
Problem
Existing stretch articles, such as disposable diapers and incontinence products, face challenges with adhesive attachment of elastomeric stretch yarns to substrates, which reduces elasticity at attachment points, is costly, and prone to creep due to inadequate bonding methods.
Innovation Solution
The use of elastomeric propylene-based polymer stretch yarns that can be mechanically bonded directly to a substrate without adhesives, utilizing techniques like ultrasonic welding and heat pressing to create strong, adhesive-free bonds, ensuring durability and reduced creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive attachment is used to bond stretch yarns to substrates, then bonding strength is improved, but elasticity is reduced at attachment points and creep occurs
Solution Approach 1:
The patent removes adhesives from the bonding process entirely, extracting the harmful element that causes elasticity loss and creep. Instead of using adhesive attachment, the invention employs mechanical interlocking through substrate apertures and ultrasonic welding to achieve bonding without compromising the elastic properties of the stretch yarns.
Solution Approach 2:
The patent replaces the chemical bonding mechanism (adhesive) with mechanical bonding methods. Specifically, it uses ultrasonic welding to create mechanical bonds between the stretch yarns and substrate, and employs mechanical interlocking through apertures, substituting the adhesive system with a purely mechanical bonding approach that preserves elasticity.
2Reliability
If adhesive attachment is used to bond stretch yarns to substrates, then bonding is achieved, but manufacturing cost increases
Solution Approach 1:
The patent eliminates adhesives from the manufacturing process, removing the associated costs of adhesive materials, application equipment, and environmental compliance. This extraction of the adhesive system reduces manufacturing complexity and cost while maintaining bonding reliability through alternative mechanical methods.
Solution Approach 2:
The substrate and stretch yarns are designed to bond to each other through their own structural features without requiring external adhesive materials. The substrate's aperture structure and the yarn's configuration enable self-bonding through mechanical interlocking and ultrasonic welding, eliminating the need for separate adhesive components and reducing material costs.
3Reliability
If adhesive attachment is used to bond stretch yarns to substrates, then bonding is achieved, but the process becomes time-consuming and messy
Solution Approach 1:
The patent replaces the messy, multi-step adhesive application process with clean, efficient mechanical bonding methods. Ultrasonic welding provides rapid, precise bonding without the messiness of adhesive application, and mechanical interlocking through apertures eliminates the need for adhesive spreaders, applicators, and curing processes, thereby improving manufacturing efficiency.
4Reliability
If spandex or rubber threads are used for stretch yarns, then elasticity is achieved, but bonding to substrate becomes difficult requiring more adhesive
Solution Approach 1:
The patent removes the need for adhesives to bond spandex or rubber threads to the substrate. By using mechanical interlocking through substrate apertures and ultrasonic welding, the invention eliminates the adhesive requirement that would otherwise be needed to bond these difficult-to-attach elastic materials, simplifying the manufacturing process.
Solution Approach 2:
The substrate aperture structure serves as an intermediary mechanism that facilitates bonding between the stretch yarns and substrate without requiring adhesives. The aperture provides a mechanical interface that enables secure attachment of elastic yarns through interlocking and ultrasonic welding, mediating the bonding process for materials that are difficult to bond directly.
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 enhances the elasticity and durability of stretch articles by eliminating adhesive-related issues, reducing material costs, and improving the bonding process, resulting in more reliable and cost-effective production.
Implementation Method 1
utilizing techniques like ultrasonic welding and heat pressing to create strong, adhesive-free bonds
Implementation Method 2
utilizing techniques like ultrasonic welding and heat pressing to create strong, adhesive-free bonds
Data Source
Figure 1
Figure 2
AI summary
A stretch article comprising: a substrate comprising a substrate material, and at least one stretch yarn comprising an elastomeric propylene-base dpolymer, wherein the stretch yarn is bonded to the substrate and wherein the stretch yarn is capable of being mechanically bonded directly to the substrate surface.