Vibration-absorbing Rubber Composition for Engine Mounts
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Solution Overview
Problem
Current vibration-absorbing rubber compositions used in automotive applications, such as torsional dampers and engine mounts, face challenges in achieving adequate heat resistance while maintaining good dynamic and tensile properties, particularly due to inferior static spring and compression set properties.
Innovation Solution
A rubber composition combining natural rubber or a blend of natural and diene synthetic rubber with bismaleimide and a dithiocarbamic acid metal salt, specifically with a benzene ring, is used, along with sulfur, to enhance hardness and compression set properties, and improve heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural rubber or diene rubber is used as main component for good vibration-absorbing properties, then vibration-absorbing performance is improved, but heat resistance becomes inferior
Solution Approach 1:
The patent uses a composite rubber composition combining natural rubber (NR) with diene synthetic rubber (BR or SBR) in specific ratios (NR 40-90 parts, BR 10-60 parts, or SBR 10-60 parts per 100 parts total rubber). This composite approach allows the formulation to achieve both good vibration-absorbing properties from NR and improved heat resistance through the diene rubber component, while also incorporating bismaleimide and dithiocarbamic acid metal salt for crosslinking enhancement.
2Temperature
If bismaleimide with thiazole or thiuram accelerator is used to improve static spring and compression set, then heat resistance is improved, but formulation complexity increases
Solution Approach 1:
The patent specifies precise parameter ranges for the formulation: bismaleimide at 0.2-10 parts per 100 parts rubber, dithiocarbamic acid metal salt at 0.2-5 parts per 100 parts rubber composition, and sulfur at 0.1-5 parts per 100 parts rubber composition. These controlled parameter changes optimize the crosslinking system to achieve improved heat resistance and compression set properties while maintaining manageable formulation complexity through defined dosage ranges.
3Temperature
If crosslinking agents are increased to improve compression set property, then heat resistance is improved, but tensile physical properties may deteriorate
Solution Approach 1:
The patent employs a multi-component crosslinking system where bismaleimide (0.2-10 parts), dithiocarbamic acid metal salt (0.2-5 parts), and sulfur (0.1-5 parts) work in complementary roles. This localized functional distribution within the crosslinking network allows different crosslinking mechanisms to operate synergistically, improving compression set and heat resistance while the controlled ratios prevent excessive crosslinking that would harm tensile properties. The dithiocarbamic acid metal salt specifically targets compression set improvement without compromising overall tensile strength.
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 proposed composition effectively improves static spring and compression set properties while maintaining low dynamic magnification and tensile strength, making it suitable for high-temperature automotive applications like engine mounts.
Implementation Method 1
a dithiocarbamic acid metal salt having a benzene ring... when a bismaleimide and a specific type of dithiocarbamic acid metal salt vulcanization accelerator are used in combination and formulated in natural rubber
Implementation Method 2
a bismaleimide serving as a crosslinking agent is formulated in rubber
Implementation Method 3
Most of vibration-absorbing rubber members make use, as a main component, of natural rubber or a diene rubber such as butadiene rubber, which shows good vibration-absorbing properties
Data Source
AI summary
The present invention provides a vibration-absorbing rubber composition that is characterized by containing: a rubber component which contains natural rubber or a mixture of natural rubber and a diene-based synthetic rubber as a primary component; bismaleimide; and a metal salt of a dithiocarbamic acid having a benzene ring. According to this vibration-absorbing rubber composition, it is possible to improve changes in static spring and improve permanent compression set while maintaining inherent characteristics such as low dynamic magnification and strength characteristics (hardness, tensile elongation, tensile strength and the like), and this vibration-absorbing rubber composition is useful as a vibration-absorbing member which requires extreme heat resistance, such as an engine mount.