Airbag Base Cloth Structure for Low Permeability at High Temperature
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Solution Overview
Problem
Current base cloths for airbags fail to maintain airtightness and prevent bursting at high temperatures, especially with larger airbag sizes and high-temperature inflators, due to insufficient stress resistance and increased air permeability.
Innovation Solution
A woven fabric base cloth with specific yarn tenacity and force strain characteristics, measured by Edgecomb Resistance, is developed, featuring a plain weave structure and a heat treatment process that maintains airtightness and low air permeability from low to high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the airbag volume is increased to provide wider protection, then the protection capability is improved, but the stress on the boundary between inflated and non-inflated parts increases and airtightness deteriorates
Solution Approach 1:
The invention changes the physical-chemical parameters of the fiber surface by controlling the presence of specific substances (oils, waxes, surfactants, etc.) within specific ranges (0.1-5% by weight). This parameter change modifies the friction characteristics between yarns, enabling the fabric to maintain low air permeability and high airtightness even when the airbag volume is increased and subject to higher boundary stresses
Solution Approach 2:
The invention uses composite fiber structures where fibers contain multiple components including base polymers and surface-active substances (oils, waxes, surfactants, or their combinations). This composite approach creates a fiber surface with optimized friction characteristics that simultaneously provides flexibility for large volume and maintains airtightness under increased stress conditions
2Ease of manufacture
If pyrotechnic inflators are simplified to reduce unit cost, then the manufacturing cost is reduced, but the gas temperature increases and airtightness deteriorates
Solution Approach 1:
The invention employs inexpensive surface treatments using common substances like oils, waxes, or surfactants that can be applied during standard manufacturing processes. These treatments provide temporary but effective friction control that maintains airtightness under high-temperature conditions, making the solution cost-effective for simplified pyrotechnic inflator systems
Solution Approach 2:
The invention changes the thermal-friction parameters of the fiber surface to maintain optimal friction characteristics even when exposed to high-temperature gas from simplified pyrotechnic inflators. The specific substance ranges and fiber structure design ensure that the fabric maintains low air permeability despite temperature increases, allowing cost-effective inflator designs
3Reliability
If friction between yarns is increased to suppress opening at boundaries, then the airtightness is improved, but the storability deteriorates due to reduced flexibility
Solution Approach 1:
The invention precisely controls the friction parameter by limiting surface-active substances to specific concentration ranges (0.1-5% by weight). This optimized parameter range provides sufficient friction to suppress boundary opening and maintain airtightness, while simultaneously maintaining enough flexibility for proper storability and deployment
Solution Approach 2:
The invention applies a moderate amount of surface-active substances rather than maximum possible amounts. This partial action provides just enough friction enhancement to suppress opening at boundaries while avoiding excessive friction that would impair flexibility and storability, achieving an optimal balance between airtightness and operability
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 base cloth effectively suppresses opening between the inflated and non-inflated parts, exhibits low dynamic air permeability, and prevents bursting even at high temperatures, ensuring reliable airbag performance.
Implementation Method 1
a heat treatment process that maintains airtightness and low air permeability from low to high temperatures
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided are a base cloth for a material and a manufacturing method therefor, the base cloth suppressing opening of a boundary portion between an expanding part and a non-expanding part when used in a bag body, having low dynamic air permeability, and being capable of exhibiting the characteristic of being unlikely to burst even at high temperatures. A fabric base cloth for a material according to the present invention is composed of fibers having a prescribed thread breaking strength value, and for which the cloth surface is not subjected to resin coating, laminating, or a resin impregnation treatment. The base cloth for a material is characterized in that, in the curve of strong elongation characteristics (FS) of constituent fibers obtained using the Edgecomb Resistance measurement method stipulated in the ASTM D6479 standard, E1 is 3 to 25 MPa and E2 is 10 to 30 MPa for both the warp and weft in both a 25°C environment and a 150°C environment, E1 being the value obtained by dividing the ratio of the strength increase amount at a bending elongation of 0.4 to 4.4% by the total cross-sectional area of the fiber in the measuring direction, and E2 being the value obtained by dividing the ratio of the strength increase amount at an elongation of -4.8 to -0.8% from a fiber cutting point by the total cross-sectional area of the fiber in the measurement direction.