Hydrogenated Styrenic Block Copolymer for Broad Damping Adhesion
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Solution Overview
Problem
There is a need for a polymer that combines broad tan delta peak and adhesion over a broad temperature range with low peel adhesion build-up over time, particularly in applications requiring high sound or vibration damping performance and surface protection.
Innovation Solution
A hydrogenated styrenic block copolymer (HSBC) is developed, comprising specific polymer blocks derived from vinyl aromatic and conjugated diene monomers, with controlled hydrogenation levels and aromatic blockiness, achieving a tan delta peak height of 0.7 to 2 and a temperature width of 17 to 40°C, suitable for applications requiring broad adhesion and damping performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional SBCs are used to achieve high damping performance, then tan delta peak is improved, but adhesion stability over time deteriorates with peel adhesion build-up
Solution Approach 1:
The patent applies parameter changes by precisely controlling the hydrogenation level of conjugated diene units (90-99%) and adjusting the aromatic blockiness index (20-80%) to optimize both damping performance and adhesion stability. This chemical parameter modification transforms the polymer properties to achieve the desired balance between energy dissipation and adhesive performance over time
Solution Approach 2:
The patent creates a composite block copolymer structure consisting of hydrogenated styrenic blocks (A) and hydrogenated conjugated diene blocks (B) with specific architectural arrangements. This composite structure combines the rigid aromatic segments for structural integrity and adhesion with the flexible aliphatic segments for damping, resolving the contradiction between these opposing requirements
2Temperature
If SBCs are designed for broad tan delta peak, then damping temperature range is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct blocks with different functions: block A (vinyl aromatic) provides mechanical strength and structural rigidity, while block B (conjugated diene) provides flexibility and damping. The specific arrangement and composition of these blocks allow the material to exhibit both high mechanical strength and broad damping temperature range simultaneously
3Reliability
If hydrogenation level is increased to improve adhesion, then adhesion performance is improved, but processing difficulty increases
Solution Approach 1:
The patent optimizes the hydrogenation level parameter to a specific range (90-99%) that balances adhesion performance and processing ease. This precise parameter control ensures sufficient adhesion while maintaining processability, avoiding the extremes that would cause either poor adhesion or difficult processing
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 HSBC exhibits improved mechanical properties, broad adhesion temperature range, and high damping performance, making it suitable for applications such as adhesives, protective films, and over-molding thermoplastic compounds.
Implementation Method 1
Tan delta (δ) peak is the ratio of the loss to the storage modulus, characterizing the efficiency of the material to dissipate energy when deformed
Implementation Method 2
high sound or vibration damping performance over a large range of vibration frequencies and broad temperature ranges
Data Source
AI summary
A hydrogenated styrenic block copolymer (HSBC) is disclosed comprising, prior to hydrogenation, a polymer block A of at least one vinyl aromatic monomer, a polymer block B of at least one conjugated diene, and a copolymer block C of at least one vinyl aromatic monomer and 1,3-butadiene monomer. The HSBC has a total vinyl aromatic content of 15 to 60 wt. % and an aromatic blockiness index of 20 to 80%. The viscoelastic properties of HSBC show a value of a tan δ peak height of 0.7 to 2, a tan δ peak temperature of −40 to 25° C., and a temperature width value (in ° C.) at half the tan δ peak height of 17 to 40. The HSBC provides improved mechanical properties and can be used in preparation of adhesives and protective films applications.