Liquid Polyene Rubber Damping via Pendant Group Control
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Solution Overview
Problem
Existing liquid rubber compositions face challenges in balancing damping characteristics and hardness, with lower molecular weight liquid rubbers having slower crosslinking speeds and increased viscosity when blended with solid rubber, limiting their application as adhesives and dampening materials.
Innovation Solution
Development of curable liquid rubber compositions with a liquid polyene component having a high percentage of C2-C13, C2-C5, and C6-C13 pendant groups, along with a weight average molecular weight greater than 2000 g/mol, which are cured with heat-activated crosslinking agents to achieve enhanced damping properties and reduced viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If lower molecular weight liquid rubber is used to improve crosslinking speed, then crosslinking speed is improved, but viscosity decreases uncontrollably and hardness is compromised
Solution Approach 1:
The patent changes the molecular weight parameter of the liquid rubber from conventional low values to a specific range (2000-10000 g/mol), and adjusts the pendant group content parameter (20-40%) to achieve the optimal balance between crosslinking speed and viscosity control
Solution Approach 2:
The patent creates a composite liquid rubber system by combining specific polyene structures with controlled pendant groups (C2-C5 and C6-C13), forming a new material class that simultaneously achieves fast crosslinking and manageable viscosity
2Strength
If solid rubber is added to improve hardness, then hardness is improved, but viscosity increases significantly
Solution Approach 1:
The patent changes the approach from adding solid rubber to using liquid rubber with controlled molecular weight (2000-10000 g/mol) and pendant group content (20-40%), achieving hardness through molecular structure rather than phase mixing
Solution Approach 2:
The patent replaces solid rubber additives with a specifically designed liquid rubber component that provides both hardness and processability, eliminating the need for separate solid rubber additions
3Ease of operation
If higher molecular weight liquid rubber is used to reduce viscosity, then viscosity is reduced, but crosslinking speed decreases
Solution Approach 1:
The patent identifies an optimal molecular weight window (2000-10000 g/mol) that balances viscosity and crosslinking speed, neither too low nor too high, achieving both processability and reaction kinetics
4Reliability
If liquid rubber with high pendant group content is used to improve damping, then damping is improved, but molecular weight distribution becomes complex
Solution Approach 1:
The patent introduces local pendant groups (C2-C5 and C6-C13) at specific positions along the polyene backbone, creating localized damping zones without complicating the overall molecular architecture
Solution Approach 2:
The patent controls the pendant group content within a specific range (20-40%) to achieve optimal damping while maintaining manageable molecular structure and synthesis complexity
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 compositions exhibit improved damping performance with a loss factor greater than 0.51 across a wide temperature range and a swelling ratio from 40% to 170%, while maintaining suitable hardness and lower viscosity, enabling easier application at ambient conditions.
Implementation Method 1
capable of being cured by crosslinking reactions to provide solid elastomeric compositions
Implementation Method 2
loss factor value (tan δ)
Data Source
AI summary
A curable liquid rubber composition including at least one liquid polyene component and at least one heat activated crosslinking agent. The liquid polyene component may be a single polyene or a blend of polyenes. In one embodiment, the liquid polyene component may contain on a molar basis, at least one monomer that results in at least 45 molar percent of C2-C13 pendant groups. In another embodiment, the liquid polyene component may contain on a molar basis at least one monomer that results in at least 20 molar percent of C2-C5 pendant groups, and at least one monomer that results in at least 7 molar percent of C6-C13 pendant groups. After curing, the liquid rubber composition may have a loss factor greater than 0.51, a maximum loss factor temperature greater than -10°C, and a swelling ratio in toluene from 40% to 170% by weight.