Polyester Sound-Absorbing Air Duct With Adhesive-Free Thermal Bonding

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Solution Overview

Problem

Conventional sound-absorbing air ducts for vehicles, made from synthetic resins like PVC and PU, release volatile organic compounds during incineration and are difficult to recycle due to material separation issues, and they require separate adhesive materials for assembly, complicating manufacturing.

Innovation Solution

A sound-absorbing air duct composed of polyester fibers with a low melting point, featuring a mixture of high and low melting point polyester fibers in non-woven fabrics and a polyester resin film, which eliminates the need for additional adhesives and facilitates recycling by using a thermal compression process for assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional synthetic resins (PVC, PU) are used for sound-absorbing air ducts, then sound absorption performance is achieved, but volatile organic compounds are released during incineration and recycling is difficult

Engineering Contradiction:
ImproveVOC release during incinerationVSAvoidRecyclability
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from conventional PVC/PU resins to polyester resin, which has different combustion characteristics that eliminate VOC release during incineration. This material substitution resolves the contradiction by providing both sound absorption performance and improved environmental compatibility without compromising manufacturability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent enables recovery and recycling of the air duct material by using polyester resin that can be easily separated and reused. The material can be discarded cleanly without harmful emissions and recovered for reuse, resolving the contradiction between harmful factors during disposal and recyclability

Inventive Principle:
Principle #34Discarding and recovering

2Ease of manufacture

If separate adhesive materials are used for assembling air duct components, then assembly is achieved, but manufacturing complexity increases

Engineering Contradiction:
ImproveAssembly processVSAvoidNumber of materials
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the adhesive function into the polyester resin material itself, which inherently provides adhesion properties. This eliminates the need for separate adhesive materials, reducing manufacturing complexity while maintaining assembly capability through the resin's own bonding characteristics

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The polyester resin serves multiple functions simultaneously: sound absorption, structural integrity, and adhesion between components. This multi-functionality resolves the contradiction by eliminating the need for specialized adhesive materials while maintaining all necessary assembly functions

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Temperature

If high melting point polyester fibers are used alone, then heat resistance is maintained, but thermal adhesion during assembly is insufficient

Engineering Contradiction:
ImproveHeat resistanceVSAvoidThermal adhesion
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent uses a composite structure combining high melting point polyester fibers for heat resistance with low melting point polyester fibers for thermal adhesion. This composite material approach resolves the contradiction by integrating both thermal stability and bonding capability within the same material system

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different melting point characteristics to different functional requirements within the same material system. High melting point fibers provide heat resistance where needed, while low melting point fibers provide thermal adhesion during assembly, resolving the contradiction through localized functional differentiation

Inventive Principle:
Principle #3Local quality

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 provides improved thermal adhesion and heat resistance, enabling efficient sound absorption and easy recyclability of the air duct components, enhancing both sound absorption performance and manufacturing productivity.

Implementation Method 1

a sound-absorbing air duct for a vehicle containing a polyester fiber having a low melting point, in which the air duct is made of a polyester-based resin

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

improved thermal adhesion and heat resistance, such that a separate adhesive material is not required for adhesion between components

Methodology Applied
Scientific EffectThermal adhesion:

Implementation Method 3

A method for reducing a sound discharged from the engine and the like by the intake system includes a method of reducing the engine discharge noise of a specific frequency by installing the resonator in the air duct

Methodology Applied
Scientific EffectSound absorption: Acoustic Absorption

Data Source

PatentEP3785894B1Sound-absorbing air duct for vehicle containing polyester fiber with low melting point
Publication Date: 2024.05.01 HUVIS CORP
  • EP3785894B1 patent drawingFigure 1~3

AI summary

A sound-absorbing air duct for a vehicle includes a lower non-woven fabric and an upper non-woven fabric sandwiching wires therebetween; and a film made of a polyester resin having a low melting point and disposed on the upper non-woven fabric, wherein each of the lower and upper non-woven fabrics includes a mixture between a first polyester fiber containing a polyester resin having a melting point higher than 250°C and a second polyester fiber containing a polyester resin having a low melting point and having a softening point of 100°C to 150°C, wherein the second polyester fiber includes a polyester resin having a low melting point composed of: an acid component including terephthalic acid or an ester-forming derivative thereof; and a diol component including 2-methyl-1,3-propanediol, 2-methyl-1,3-pentanediol, and ethylene glycol.