Vehicle Trim Bonding Layer for Noise Attenuation Without Cracking

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Solution Overview

Problem

Current automotive trim materials face challenges in achieving noise attenuation and weight increase without increasing part thickness, while maintaining processability and avoiding cracking, due to high filler content and limited processing equipment capabilities.

Innovation Solution

A noise attenuating trim part with a bonding mass layer composed of a thermoplastic elastomeric polyolefin-based compound material with 55-70% inert filler and 0.2-0.8% fatty acid content, which adheres to and penetrates the pile layer, acting as a fiber/tuft lock and binder, replacing traditional tuft/fiber lock layers and simplifying production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high filler content (above 50%) is used to increase weight and noise absorption, then acoustic performance is improved, but material viscosity increases making it difficult to process and requiring heavy equipment

Engineering Contradiction:
Improvefiller contentVSAvoidprocessability
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the bonding mass layer by specifying a thermoplastic polyolefin elastomer matrix with controlled filler content (35-85% by mass) and adding specific additives including fatty acids (0.1-2.0% by mass), processing aids, and lubricants. These parameter adjustments optimize the balance between viscosity for processability and filler content for acoustic performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The bonding mass layer is formulated as a composite material combining thermoplastic polyolefin elastomer with inert filler particles, fatty acids, and processing aids. This composite structure allows the material to achieve both high filler content for noise attenuation and controlled viscosity for ease of processing through extrusion and calendaring.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If heavily filled thermoplastic elastomeric layers are used to increase weight, then noise absorption is improved, but the material becomes difficult to process requiring heavy equipment

Engineering Contradiction:
Improvepart weightVSAvoidprocessing difficulty
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent adjusts material parameters by controlling filler content within 35-85% by mass and adding fatty acids (0.1-2.0% by mass) and processing aids to modify viscosity and processability, enabling the material to be processed with standard equipment while maintaining high weight for noise absorption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Fatty acids and processing aids act as intermediary substances that facilitate the processing of heavily filled materials. These additives reduce friction and improve flow characteristics during extrusion and calendaring, enabling easier processing without sacrificing the high filler content needed for weight and acoustic performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If multiple process steps (extrusion, calendaring, cutting, vacuum forming) are used to manufacture the trim part, then production completeness is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveproduction completenessVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple manufacturing operations into an integrated process flow where the bonding mass layer is extruded, calendared to desired thickness, cut to shape, and vacuum formed in sequence. The material formulation enables these operations to be performed efficiently with standard equipment, reducing overall process complexity while maintaining production completeness.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If variable thickness is required in the trim part, then acoustic performance is improved, but achieving variable thickness becomes difficult with current processes

Engineering Contradiction:
Improvethickness controlVSAvoidvariable thickness capability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent enables local quality variations in the bonding mass layer by using calendaring to create regions of different thickness. The material formulation with controlled viscosity and filler content allows the calendaring process to achieve precise thickness control in different areas, enabling variable thickness designs that optimize acoustic performance in specific regions.

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 enables easier processing, reduced material costs, and improved durability by maintaining acoustic performance and stiffness, while allowing for variable thickness and weight distribution, reducing the risk of cracking and delamination.

Implementation Method 1

a bonding mass layer (B) composed of a thermoplastic elastomeric polyolefin-based compound material (TPO) with an inert filler content between 55 and 70% by weight and a fatty acid content between 0.2 and 0.8% by weight based on the weight of the overall bonding mass layer, wherein the bonding mass layer is able to bond to the adjacent layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3812151B1Noise attenuating trim part for a vehicle
Publication Date: 2022.08.03 AUTONEUM MANAGEMENT AG
  • EP3812151B1 patent drawingFigure 1~3
  • EP3812151B1 patent drawingFigure 4

AI summary

Noise attenuating trim part for a vehicle comprising a pile layer, a bonding mass layer and a backing layer whereby the bonding mass layer is bonded to the adjacent layers whereby the bonding mass layer is comprising at least thermoplastic elastomeric polyolefin based compound material (TPO) with a filler content of at least 55%, and whereby the bonding mass layer has a density of between 1.4 and 1.75kg/dm3, a viscosity of less than 50.000mPa.s and a MFI above 250 and whereby the bonding mass layer is adjacent the pile layer and partly penetrated into the lower area of the pile thereby binding the fibers and/or filaments and/or the tufts within the pile.