EPDM/PP Elastomer Damping for Vehicle Noise
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Solution Overview
Problem
EPDM/PP thermoplastic elastomers used in inner belt weather strips for vehicles exhibit low material damping properties at low temperatures, leading to noise and vibration issues, and increased compression set, which compromises sealing performance.
Innovation Solution
A thermoplastic elastomer composition comprising 80 parts by weight of EPDM with 5-ethylidene-2-norbornene and polyethylene, 30-70 parts by weight of polypropylene, 20-40 parts by weight of filler, and 60-90 parts by weight of plasticizer, with specific crosslinking density and molecular weight distribution, is developed to improve material damping and compression set, reducing friction noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the material damping is increased to reduce noise and vibration, then the friction noise and vibration are reduced, but the compression set is also increased which adversely affects the sealing performance
Solution Approach 1:
The patent changes the chemical composition parameters of the elastomer by incorporating specific ratios of EPDM (50-70 parts), PP (20-40 parts), and plasticizer (30-50 parts), along with controlled crosslinking density (2.00×10^-4 to 2.68×10^-4 mol/ml), to simultaneously optimize both damping properties and compression set characteristics
Solution Approach 2:
The patent creates a composite thermoplastic elastomer material by blending EPDM and PP polymers with controlled crosslinking, where the composite structure allows the material to exhibit both high damping properties for noise reduction and appropriate compression set for sealing performance
2Weight of moving object
If the EPDM/PP thermoplastic elastomer is used to improve recyclability and reduce density, then environmental friendliness and weight reduction are achieved, but the material damping property becomes low causing noise and vibration at low temperatures
Solution Approach 1:
The patent adjusts the compositional parameters within the EPDM/PP blend system, specifically optimizing the ratio of elastomer to plasticizer and controlling the crosslinking density, to enhance material damping properties while preserving the low density and recyclability characteristics of the thermoplastic elastomer
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 composition enhances sealing performance by simultaneously improving material damping and compression set, reducing friction noise and vibration, thereby improving the emotional quality of the vehicle's interior by minimizing noise and vibration at low temperatures.
Implementation Method 1
an EPDM/PP thermoplastic elastomer is prepared through a blend process of a thermosetting elastomer (EPDM) and a thermoplastic plastic (PP), specifically, through dynamical crosslinking in which EPDM is crosslinked during the blending process
Implementation Method 2
The composition enhances sealing performance by simultaneously improving material damping and compression set, reducing friction noise and vibration
Data Source
AI summary
A thermoplastic elastomer composition includes about 80 parts by weight of an ethylene propylene diene monomer (EPDM) including 5-ethylidene-2-norbornene (ENB) and polyethylene, about 30 parts by weight to about 70 parts by weight of polypropylene, about 20 parts by weight to about 40 parts by weight of a filler, and about 60 parts by weight to about 90 parts by weight of a plasticizer.