Polyamide-Imide Adhesion Layer for Brassiere Wire Dyeing
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Solution Overview
Problem
Existing hook and eye closures for brassieres face issues with colour uniformity during dyeing and maintainance of uniformity through multiple laundry cycles, and the use of chromic acid or phosphoric acid in surface treatments poses environmental and safety concerns.
Innovation Solution
A wire with a steel core and a polyamide coating layer, further coated with a polyamide-imide layer, which acts as an adhesion layer to prevent peeling and ensures uniform dyeing, replacing the need for chromic acid or phosphoric acid treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polyamide coating layer is applied on steel wire for hooks and eyes, then the wire can be dyed in the same dyeing process as fabric panels, but the coating layer may peel off during dyeing and laundry cycles causing colour uniformity issues
Solution Approach 1:
The patent applies a composite coating structure consisting of a polyamide-imide adhesion layer combined with a polyamide coating layer. This composite structure provides both strong adhesion to the steel core and excellent dyeing properties, preventing peeling during dyeing and laundry while enabling uniform colouring throughout the brassiere.
Solution Approach 2:
The polyamide-imide coating layer serves as an intermediary adhesion layer between the steel core wire and the outer polyamide coating layer. This intermediate layer specifically functions to prevent peeling of the polyamide coating during dyeing processes and laundry cycles, while the outer polyamide layer provides the necessary dyeing compatibility with fabric panels.
2Reliability
If chromic acid or phosphoric acid is used for surface treatment of galvanized steel, then surface conversion and adhesion are improved, but environmental and safety issues arise from handling and disposal
Solution Approach 1:
The patent replaces harmful chromic acid and phosphoric acid treatments with a polyamide-imide coating layer that can be applied without these hazardous chemicals. The polyamide-imide layer provides sufficient adhesion and surface conversion properties traditionally achieved by chromating or phosphating, but without the environmental and safety hazards associated with those chemicals.
Solution Approach 2:
The patent converts the harmful chromic acid or phosphoric acid surface treatment process into a beneficial polyamide-imide coating application. The polyamide-imide layer provides the necessary surface conversion and adhesion benefits while eliminating the harmful chemical disposal issues, turning a harmful process into an environmentally friendly one.
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 solution achieves improved colour uniformity of brassieres by preventing peeling of the polyamide coating during dyeing and laundry, maintaining uniformity over the lifetime of the garment and avoiding harmful chemical treatments.
Implementation Method 1
the polyamide-imide coating layer - acting as an adhesion layer - of peeling off of part of the polyamide coating layer during the dyeing process and/or during laundry operations
Data Source
Figure 1a~1b
Figure 2~3
AI summary
A wire (200) comprises a steel core wire (202) and a polyamide coating layer (208) at the surface of the wire (200). The polyamide is selected from the group consisting of polyamide 6, polyamide 6.6, polyamide 11 and polyamide 12. The wire (200) comprises a polyamide-imide coating layer (206) contacting the polyamide coating layer (208) at the inner side of the polyamide coating layer (208).