Nonwoven Fabric Web for Vehicle Road Noise Absorption
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Solution Overview
Problem
Conventional sound absorbing materials for vehicle exteriors have a low sound absorption coefficient in the frequency range of 800 Hz to 1000 Hz, which corresponds to road noise peaks, limiting their effectiveness in reducing noise infiltration into vehicles.
Innovation Solution
A nonwoven fabric web composed of meltblown fibers and binder fibers, where the binder fibers are arranged to be confounded with and fused at intersections with the meltblown fibers, providing a weight per unit area of 400 g/m2 to 1500 g/m2 and flexural rigidity of 2.0 N/50 mm to 20.0 N/50 mm, enhancing sound absorption in the specified frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional nonwoven fabrics are used for sound absorption, then the material structure is simple and easy to manufacture, but the sound absorption coefficient in the frequency range of 800 Hz to 1000 Hz is low
Solution Approach 1:
The patent uses a composite nonwoven fabric structure combining meltblown fibers and binder fibers with specific weight ratios (meltblown fibers: 30-70 wt%, binder fibers: 30-70 wt%). This composite structure enables the fabric to achieve high sound absorption coefficients in the 800-1000 Hz frequency range while maintaining manufacturability through established nonwoven fabric production processes.
Solution Approach 2:
The patent optimizes specific parameters including weight per unit area (400-1500 g/m²), flexural rigidity (2.0-20.0 N/50mm), and fiber composition ratios. By precisely controlling these parameters, the nonwoven fabric achieves enhanced sound absorption performance in the target frequency range while remaining compatible with conventional manufacturing methods.
2Reliability
If the weight per unit area of the nonwoven fabric is increased to improve sound absorption, then the sound absorption coefficient improves, but the flexural rigidity becomes too high affecting installation and fitting
Solution Approach 1:
The patent establishes an optimal balance by specifying weight per unit area within 400-1500 g/m² and flexural rigidity within 2.0-20.0 N/50mm. This parameter optimization ensures that the nonwoven fabric achieves sufficient sound absorption performance while maintaining appropriate flexibility for installation and conforming to vehicle body contours.
Solution Approach 2:
The combination of meltblown fibers and binder fibers in specific proportions creates a composite structure that provides both sound absorption capability and mechanical flexibility. The binder fibers hold the meltblown fibers together while allowing the fabric to bend and conform, achieving both high sound absorption and manageable rigidity.
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 nonwoven fabric web achieves an excellent sound absorption coefficient in the frequency range of 800 Hz to 1000 Hz, effectively reducing road noise infiltration into vehicles when used in sound absorbing members such as fender liners.
Implementation Method 1
binder fibers arranged so as to be confounded with the meltblown fibers and fused with the meltblown fibers at some of the compounding points
Data Source
AI summary
A nonwoven fabric web having an excellent sound absorption coefficient in a frequency range from 800 Hz to 1000 Hz when used as a sound absorbing member for a vehicle exterior. The nonwoven fabric web including a nonwoven fabric having meltblown fibers and binder fibers arranged so as to be confounded with the meltblown fibers and fused with the meltblown fibers at some of the confounding points at the very least, the weight per unit area of the nonwoven fabric being from 400 g/m2 to 1500 g/m2, and the flexural rigidity of the nonwoven fabric being from 2.0 N/50 mm to 20.0 N/50 mm.