Hydrogenated Block Copolymer Composition for Wide-Range Vibration Damping
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Solution Overview
Problem
Conventional aromatic vinyl-based elastomers do not consistently exhibit vibration damping properties across different types, particularly failing to provide sufficient performance as non-restraint type vibration damping materials, which require a wide temperature range capability.
Innovation Solution
A block copolymer with a polymer block A containing over 70 mol% of structural units from aromatic vinyl compounds and a polymer block B with 30 mol% or more from conjugated diene compounds, specifically designed to have a tan δ of 1.0 or more in a narrow temperature region, a peak tan δ within 0° C. to +50° C., and a mobility parameter M between 0.01 to 0.25 sec, ensuring effective vibration damping in non-restraint applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional aromatic vinyl-based elastomers are used, then mechanical strength and heat resistance are improved, but vibration damping performance across wide temperature range deteriorates
Solution Approach 1:
The invention uses a block copolymer composed of two distinct polymer blocks: block A containing aromatic vinyl compound units (for mechanical strength and heat resistance) and block B containing conjugated diene compound units with vinyl bonds (for vibration damping). This composite structure at the molecular level allows the material to simultaneously achieve high mechanical strength from the aromatic vinyl block and excellent vibration damping across wide temperature ranges from the conjugated diene block with vinyl bonds.
Solution Approach 2:
The invention applies local quality by creating distinct functional regions within the polymer chain through block copolymerization. Block A provides localized mechanical strength and heat resistance, while block B with vinyl bonds provides localized vibration damping capability. This spatial separation of functions within the molecular structure enables the material to exhibit both properties simultaneously without compromise.
2Reliability
If block copolymer with high vinyl bond content (30% or more) is used, then vibration damping performance is improved, but consistency across different types deteriorates
Solution Approach 1:
The invention controls the parameters of vinyl bond content in block B within a specific range (30% or more but not exceeding 60% of all isoprene units) and aromatic vinyl compound content in block A (70-100% of the block). By precisely controlling these compositional parameters, the invention achieves consistent vibration damping performance across different types of block copolymers while maintaining the required performance level.
3Temperature
If hydrogenation of conjugated diene block is performed, then heat resistance is improved, but vibration damping performance may deteriorate
Solution Approach 1:
The invention applies partial hydrogenation to the conjugated diene block B, where the hydrogenation rate is controlled to be 60% or more but not complete. This partial hydrogenation approach removes enough double bonds to improve heat resistance while retaining sufficient vinyl bond content (30% or more of isoprene units) to maintain excellent vibration damping performance. Complete hydrogenation would eliminate the vibration damping capability, so partial hydrogenation is the optimal solution.
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 block copolymer achieves high vibration damping performance across a wide temperature range, enhancing the non-restraint type vibration damping material's effectiveness by maintaining a large loss modulus G″, thus addressing the limitations of conventional elastomers.
Implementation Method 1
a block copolymer including: a polymer block (A) containing more than 70 mol % of a structural unit derived from an aromatic vinyl compound, and a polymer block (B) containing 30 mol % or more of a structural unit derived from a conjugated diene compound
Implementation Method 2
tan δ measured in accordance with JIS K7244-10 (2005), under conditions including a strain amount of 0.1 %, a frequency of 1 Hz, a measurement temperature of −70 to 100° C., and a temperature rise rate of 3° C./min, is 1.0 or more
Data Source
AI summary
A block copolymer including a polymer block (A) containing more than 70 mol % of a unit derived from an aromatic vinyl compound, and a polymer block (B) containing 30 mol % or more of a unit derived from a conjugated diene compound is provided. The block copolymer satisfies the conditions: (1): a content of the polymer block (A) in the block copolymer is 1 to 70% by mass; (2): a maximum width of a series of temperature regions where tan δ measured in accordance with JIS K7244-10 (2005), under conditions including a strain amount of 0.1%, a frequency of 1 a measurement temperature of −70 to 100° C., and a temperature rise rate of 3° C./min, is 1.0 or more is less than 16° C.; (3): a temperature at a peak position of tan δ in the condition (2) is 0° C. to +50° C.; and (4): a mobility parameter M indicating a mobility of the polymer block (B) is 0.01 to 0.25 sec.