Polyamide Airbag Fabric for Low Gas Leakage and Fast Deployment
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Solution Overview
Problem
Current airbag technologies face challenges in maintaining deployment speed and gas utilization efficiency, especially under high-temperature and high-humidity conditions, leading to potential airbag module size increases and reduced impact absorption performance.
Innovation Solution
The development of an airbag fabric using polyamide 6·6 fibers with specific properties, including controlled thermal stress, air permeability, and the addition of elements like copper and iodine, which enhances heat resistance and maintains deployment speed and gas utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a non-coated airbag fabric is used to reduce weight, then the weight of the airbag is reduced, but the gas utilization efficiency decreases due to insufficient utilization of deployment gas
Solution Approach 1:
The patent changes the physical and chemical parameters of the polyamide fiber, specifically controlling the thermal stress at 230°C to be 0.33 to 1.20 cN/dtex and the air permeability at 200 kPa to be 10 to 200 cc/cm²/sec. These parameter optimizations enable the non-coated fabric to maintain low weight while achieving sufficient gas utilization efficiency through controlled porosity and thermal stability.
Solution Approach 2:
The patent uses composite polyamide 6·6 fibers containing specific elements (copper: 10-500 ppm, iodine: 100-3500 ppm) to create a multifunctional material that simultaneously provides heat resistance, controlled air permeability, and mechanical strength, resolving the contradiction between weight reduction and gas utilization.
2Weight of moving object
If polyester fabric is used to reduce weight, then the airbag weight is reduced, but the fabric may melt and rupture due to burning residue from the propellant
Solution Approach 1:
The patent selects polyamide 6·6 fiber with a melting point of 250°C or higher, which is significantly higher than the temperature of propellant burning residue. This parameter change in melting temperature ensures the fabric maintains structural integrity and reliability under high-temperature conditions while still achieving weight reduction.
Solution Approach 2:
The patent replaces polyester fabric (which has lower heat resistance) with polyamide 6·6 fabric that offers superior thermal stability. Although polyamide may be slightly more expensive, it eliminates the risk of melting and rupture, providing a reliable, long-lasting solution that maintains safety without sacrificing weight reduction goals.
3Object-affected harmful factors
If the air permeability is increased to reduce impact, then the impact absorption is improved, but the deployment gas leakage increases
Solution Approach 1:
The patent optimizes the air permeability parameter to a specific range of 10 to 200 cc/cm²/sec at 200 kPa pressure. This controlled permeability allows the fabric to absorb impact effectively while preventing excessive deployment gas leakage, resolving the contradiction between impact absorption and gas retention.
Solution Approach 2:
The patent applies a moderate level of air permeability rather than maximizing it. By controlling the permeability to a partial level (10-200 cc/cm²/sec), the fabric achieves sufficient impact absorption without excessive gas leakage, demonstrating the principle of partial action where moderate optimization of one parameter prevents over-optimization that would cause adverse effects.
4Stress or pressure
If the inflator volume is increased to compensate for gas leakage, then the deployment pressure is maintained, but the airbag module size increases
Solution Approach 1:
By changing the fabric parameters (air permeability: 10-200 cc/cm²/sec, thermal stress: 0.33-1.20 cN/dtex at 230°C), the patent reduces deployment gas leakage, which allows the use of a smaller inflator volume while maintaining the required deployment pressure, thus reducing the overall airbag module size.
Solution Approach 2:
The patent converts the potential harm of gas leakage into a benefit by optimizing the fabric's air permeability and thermal stress characteristics. The controlled porosity and thermal stability of the polyamide 6·6 fabric transform what would be a loss (gas leakage) into a design advantage, enabling smaller component sizes while maintaining performance.
5Stress or pressure
If thermal stabilizer is added to maintain pressure resistance after heat treatment, then the pressure resistance is improved, but the deployment speed may be affected
Solution Approach 1:
The patent optimizes the thermal stress parameter of the polyamide 6·6 fiber at 230°C to be 0.33 to 1.20 cN/dtex. This parameter optimization ensures the fabric maintains pressure resistance after heat treatment while preserving deployment speed, as the thermal stress control prevents excessive fiber stiffening that would slow deployment.
Solution Approach 2:
The patent applies local quality by controlling the thermal stress characteristics specifically at the fiber level (0.33-1.20 cN/dtex at 230°C) rather than adding bulk thermal stabilizers throughout the fabric. This localized property control maintains pressure resistance where needed (in the fiber structure) without affecting the overall deployment dynamics.
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 airbag fabric ensures high-speed deployment with reduced gas leakage, maintaining performance even after thermal aging, and provides a lightweight, reliable airbag module with improved burst resistance and dimensional stability.
Implementation Method 1
in the thermal stress of the constituent yarn as measured under the conditions of an initial load of 0.02 cN/dtex, a yarn length of 25 cm and a temperature rise rate of 80° C./min, the summed thermal stress of the total of the warp yarn and the weft yarn at 230° C. is from 0.33 to 1.20 cN/dtex
Implementation Method 2
the air permeability of the fabric under a pressure of 200 kPa is from 10 to 200 cc/cm2/sec
Data Source
AI summary
An object of the present invention is to provide an airbag module ensuring that when an airbag fabricated using a fabric composed of a polyamide yarn excellent in heat resistance is deployed by an inflator gas, the deployment occurs without loss of the gas and an excessive amount of generated gas is not necessary, as a result, the inflator is reduced in weight, and the airbag module of the present invention comprises an airbag fabric composed of a polyamide yarn, wherein the air permeability of the fabric under a pressure of 200 kPa is from 10 to 200 cc/cm2/sec and in the thermal stress of the constituent yarn as measured under the conditions of an initial load of 0.02 cN/dtex, a yarn length of 25 cm and a temperature rise rate of 80° C./min, the summed thermal stress of the total of the warp yarn and the weft yarn at 230° C. is from 0.33 to 1.20 cN/dtex.