Polyester Air-Bag Seam Fabric for Hot Inflation Integrity
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Solution Overview
Problem
Vehicle air-bags made from polyester fabrics face challenges in matching the performance of nylon-based air-bags, particularly in resisting rupture during inflation and maintaining integrity in hot conditions, due to issues like seam combing and thermal creep.
Innovation Solution
A polyester air-bag fabric with specific properties, including an elongation at break of 12% to 20%, instantaneous thermal creep above 0.5% at 100°C, and tenacity of at least 770 mN/tex, is developed, which can be coated or uncoated, to reduce permeability and prevent seam combing, while allowing for reduced coating usage and improved performance in hot environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyester fabric is used instead of nylon to reduce cost and environmental impact, then manufacturing cost and environmental friendliness are improved, but resistance to rupture during inflation and maintenance of integrity in hot conditions deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the tenacity (≥770 mN/tex), elongation at break (12%-20%), and instantaneous thermal creep (>0.5% at 100°C) of polyester fibres to achieve both cost reduction and maintained reliability during inflation
Solution Approach 2:
The patent uses composite materials by combining polyester fibres with specific properties in a woven fabric structure, creating a composite system that achieves both economic and performance requirements for air-bag applications
2Temperature
If polyester fabric with specific elongation and thermal creep properties is used, then performance in hot environments is improved, but seam combing during hot module deployment increases
Solution Approach 1:
The patent resolves this contradiction by optimizing the balance between elongation at break (12%-20%) and instantaneous thermal creep (>0.5% at 100°C) parameters, where the specific combination prevents excessive seam separation while maintaining hot environment performance
Solution Approach 2:
The patent applies local quality by using polyester fibres with specifically tailored properties in seam regions, where the fibres' controlled thermal creep and elongation characteristics locally address the seam combing issue while maintaining overall air-bag performance
3Reliability
If coating is applied to reduce gas permeability, then air-tightness is improved, but weight and cost increase
Solution Approach 1:
The patent uses parameter changes in the fibre properties (tenacity, elongation, thermal creep) to achieve the primary air-tightness function, thereby reducing or eliminating the need for additional coating layers and their associated weight and cost
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 fabric effectively minimizes gas leakage and maintains air-bag pressure, reducing costs and weight, while performing well in both ambient and hot conditions by balancing elongation and thermal creep properties.
Implementation Method 1
having an instantaneous thermal creep, when measured using thermal analyser TA Instruments model 2940, a sample bundle of 65 decitex, 10mm and loaded to give a stress of 8.83N/tex, above 0.5% at 100° C
Implementation Method 2
having an elongation at break of around 12% to 20%, and also having an instantaneous thermal creep... and further wherein the tenacity of the fibres is at least 770mN/tex
Data Source
Figure 1
AI summary
A fabric for a seam region of an inflatable air-bag, the fabric comprising fibres formed from polyester and having an elongation at break of around 12 % to 20%, and also having an instantaneous thermal creep above 0.5 % at 100 °C.