PVB-Modified EPDM Rubber for High Damping Vibration Control
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Solution Overview
Problem
Ethylene-alpha-olefin rubber compositions used in vibration control devices have limited damping capabilities, with typical tan δ values ranging from 0.05 to 0.1, which is insufficient for high-performance applications, and existing methods to increase damping often degrade other desirable properties or are unpredictable.
Innovation Solution
Incorporating polyvinylbutyral (PVB) and a compatibilizer like chlorinated polyethylene (CPE) into ethylene-alpha-olefin elastomer compositions, such as EPDM, to significantly increase damping characteristics, as measured by tan δ, while maintaining or improving other properties like heat resistance and compatibility with metal adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional ethylene-alpha-olefin rubber compositions are used, then heat resistance and ease of incorporation of fillers are maintained, but damping capability is insufficient with tan δ values only in the 0.05 to 0.1 range
Solution Approach 1:
The patent combines ethylene-alpha-olefin elastomer with polyvinyl butyral and peroxide curative to create a composite rubber composition. This composite structure enables the material to achieve high damping capability (tan δ ≥ 0.2) while maintaining heat resistance, as the peroxide-cured ethylene-alpha-olefin matrix provides thermal stability while the polyvinyl butyral phase contributes to energy dissipation through its viscoelastic properties.
2Loss of energy
If known methods such as adding more filler or changing curative amounts are used to increase damping, then damping may increase, but other properties of the rubber or overall balance of properties are negatively affected
Solution Approach 1:
The patent changes the chemical composition parameters by introducing polyvinyl butyral as a specific additive (5-50 parts by weight per 100 parts of elastomer) and using peroxide curative systems. This parameter change achieves significant damping improvement (tan δ ≥ 0.2) without compromising other properties, as the polyvinyl butyral phase enhances energy dissipation while the peroxide-cured matrix maintains structural integrity and overall property balance.
3Reliability
If ethylene-alpha-olefin elastomers are used, then peroxide curing provides better compression set and heat resistance, but the elastomers are very resilient with low damping characteristics
Solution Approach 1:
The patent creates a composite system where peroxide-cured ethylene-alpha-olefin elastomer serves as the continuous matrix providing excellent compression set resistance and heat resistance, while dispersed polyvinyl butyral phases (5-50 parts per 100 parts elastomer) provide high damping capability. This composite structure reconciles the contradiction by allowing the matrix to maintain structural reliability while the dispersed phase contributes energy dissipation through its viscoelastic behavior.
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 addition of PVB and CPE increases damping by at least 30% over a temperature range of 50 to 100° C., providing improved vibration absorption without degrading other properties, thus enhancing the performance of vibration control devices like torsional vibration dampers and engine mounts.
Implementation Method 1
The polyvinylbutyral may be present in an amount effective for substantially increasing the vibration damping character of the composition as indicated by at least a 30% increase in tan δ at a temperature in the range from 50 to 100° C.
Implementation Method 2
The present invention is directed to an ethylene-alpha-olefin rubber composition with sufficiently improved damping characteristics for use in torsional vibration dampers and other vibration absorbing devices
Data Source
AI summary
A torsional vibration damper or other vibration damping device with a rubber vibration absorbing element. The rubber element is a peroxide-cured composition based on 100 parts of ethylene-alpha-olefin elastomer, and 5 to 100 parts of polyvinyl butyral polymer which may have a molecular weight from about 40,000 to about 250,000. The composition may also include a compatibilizer or homogenizer, such as chlorinated polyethylene. The polyvinyl butyral increases the damping of the composition, and the compatibilizer improves the temperature stability of the damping.