Silicone-Free Bra Manufacturing with Reactive Polyurethane Adhesive
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Solution Overview
Problem
Existing methods for manufacturing underwear, such as bras, face challenges in achieving optimal comfort and preventing skin irritation due to the use of elastic fabrics and silicone elements, which can be harmful and problematic during thermo-forming.
Innovation Solution
A method involving two fabric layers with a silicone-free thermo-adhesive polyurethane film and reactive hotmelt polyurethane glue is used to join the layers without elastics or silicone, allowing for thermoforming without damage and ensuring comfort and wearability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If silicone elements are used to provide elasticity and join fabric layers, then comfort and wearability are improved, but health safety deteriorates and thermo-forming capability worsens
Solution Approach 1:
The patent removes silicone elements entirely from the bra construction, extracting the harmful substance while maintaining the joining function through alternative means (thermo-adhesive polyurethane film and reactive polyurethane glue). This resolves the contradiction by eliminating the source of health concerns and thermo-forming interference while preserving structural integrity.
Solution Approach 2:
The patent changes the material parameters from silicone-based elasticity to polyurethane-based elasticity with specific reactive properties. The reactive polyurethane glue undergoes chemical cross-linking at controlled temperatures below 200°C, achieving the desired elasticity and joining strength without the harmful effects of silicone, thus resolving both health safety and thermo-forming compatibility issues.
2Ease of operation
If elastic fabric strips are used to achieve elasticity, then comfort is improved, but skin irritation increases
Solution Approach 1:
The patent eliminates traditional elastic fabric strips that cause skin irritation and replaces them with a silicone-free polyurethane system. The thermo-adhesive polyurethane film and reactive polyurethane glue provide the necessary elasticity and joining function without the harmful effects on skin, thus resolving the contradiction between comfort and skin irritation.
3Shape
If thermo-forming is performed at high temperatures to shape the bra, then aesthetic form is improved, but silicone material melts and damages the article
Solution Approach 1:
The patent removes silicone material from the construction, eliminating the risk of melting during thermo-forming. The silicone-free polyurethane system withstands the thermo-forming process temperatures without degradation, allowing high-temperature shaping while maintaining material integrity and resolving the contradiction between aesthetic form and material reliability.
Solution Approach 2:
The patent changes the material composition from silicone to polyurethane with specific thermal stability properties. The reactive polyurethane glue undergoes cross-linking at temperatures suitable for thermo-forming (below 200°C), enabling the bra to achieve its aesthetic form through high-temperature shaping while the material remains intact and reliable.
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 method achieves high comfort and wearability characteristics in underwear without the need for elastics or silicone, ensuring the bra's shape and safety during thermo-forming, while maintaining the desired aesthetic and functional properties.
Implementation Method 1
triggering a chemical cross-linking process to solidify it definitively for the definitive and permanent fixing of the parts
Implementation Method 2
heat-seal said portions on said second fabric layer by hot pressing
Implementation Method 3
reactivating the reactive polyurethane glue to bring it temporarily in a liquid phase, suitable for penetrating through the fibers of the fabrics to be joined
Data Source
AI summary
A method of manufacturing a bra, comprising providing a first fabric layer as an outer layer, a second fabric layer as an inner layer, and a material made of thermo-adhesive polyurethane film that joins elements between the two fabric layers in a finished bra; sprinkling the first fabric layer on a side facing the second fabric layer with a reactive hotmelt polyurethane glue, which is reactivated only once; applying the thermo-adhesive polyurethane film on a side of the second fabric layer facing the first fabric layer; superimposing the two fabric layers such that the side of the first fabric layer covered with the glue faces the second layer and the thermo-adhesive polyurethane film portions applied to the second fabric layer face the first fabric layer; joining the two layers by hot-pressing with the thermo-adhesive polyurethane film portions, and reactivating the polyurethane glue to become temporarily in a liquid phase and triggering a cross-linking process causing the glue to solidify permanently.