Vibration-damping rubber composition and vibration-damping rubber member
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Solution Overview
Problem
Conventional vibration-damping rubber compositions using large-particle-size silica face durability issues and scorching problems during long-term storage, while compositions with silane coupling agents tend to scorch easily, compromising durability and dynamic-to-static modulus ratio.
Innovation Solution
A vibration-damping rubber composition incorporating a silica with a silanol group density of 4 groups/nm2 or greater, a BET specific surface area of 13 to 60 m2/g, and an average particle diameter of 3 to 10 μm, combined with a silane coupling agent having both sulfide and mercapto groups, which inhibits rapid vulcanization and enhances scorch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silane coupling agent is used to improve dispersion of silica and bonding, then dynamic-to-static modulus ratio is reduced, but rubber composition tends to scorch during long-term storage
Solution Approach 1:
The patent changes the chemical composition parameters of the silane coupling agent by selecting mercapto-silane with specific sulfur content (0.1-5 mass%), which modifies the vulcanization kinetics to reduce scorch tendency while maintaining low dynamic-to-static modulus ratio
Solution Approach 2:
The mercapto-silane coupling agent acts as an intermediary that mediates between silica dispersion requirements and scorch resistance, providing both good silica-rubber bonding and controlled vulcanization speed through its sulfur-containing functional groups
2Reliability
If sulfide-based or mercapto-based silane coupling agent is used to improve durability, then bonding between silica and rubber is enhanced, but scorching of rubber composition proceeds more easily
Solution Approach 1:
The patent optimizes the sulfur content parameter of the mercapto-silane coupling agent to be 0.1-5 mass%, which provides sufficient bonding strength while controlling the vulcanization speed to prevent excessive scorching
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 achieves high durability and a low dynamic-to-static modulus ratio while exhibiting excellent scorch resistance, outperforming comparative examples that used silane coupling agents without sulfide groups or silica outside the specified parameters.
Implementation Method 1
a silane coupling agent having a sulfide group and a mercapto group in the molecule
Implementation Method 2
the crosslinked structure of the polymer rubber and bonding between the silica and the polymer rubber using a silane coupling agent
Implementation Method 3
vibration-damping rubber composition and vibration-damping rubber member used for vibration-damping applications
Implementation Method 4
high durability and a low dynamic-to-static modulus ratio
Data Source
AI summary
Provided are a vibration-damping rubber composition and a vibration-damping rubber member which have excellent durability, can attain a reduction in dynamic-to-static modulus ratio, and can exhibit excellent scorch resistance even in wet-heat environments, etc. This vibration-damping rubber composition comprises a diene-based rubber composition comprising the following (A) to (C). (A) A diene-based rubber. (B) Silica having a silanol group density of four groups per nm2 or greater, a BET specific surface area of 13-60 m2/g, and an average particle diameter of 3-10 μm. (C) A silane coupling agent having a sulfide group and a mercapto group in the molecule.