EBENB Rubber Composition for High-Pressure Hydrogen Sealing
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Solution Overview
Problem
Conventional rubber materials, such as NBR, FKM, and EPDM, fail to provide sufficient low-temperature sealing and blister resistance for high-pressure hydrogen apparatuses, leading to potential leakage and rubber destruction due to inadequate hydrogen gas diffusion.
Innovation Solution
A rubber composition using an ethylene/butene/ethylidene norbornene terpolymer (EBENB) is developed, which offers excellent low-temperature sealing properties and blister resistance by allowing quick hydrogen gas diffusion, along with the incorporation of fillers, crosslinkers, and processing aids to enhance fabricability and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rubber materials (NBR, FKM, IIR) are used for sealing parts, then the sealing part can be manufactured with conventional materials, but the low-temperature sealing properties are insufficient leading to potential leakage
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber material by using EBENB (ethylene/butene/ethylidene norbornene terpolymer) with specific compositional ratios: ethylene units 40-80 mol%, butene units 10-50 mol%, and ethylidene norbornene units 1-10 mol%. This parameter change enables the material to maintain sealing properties at low temperatures down to -60°C while preventing hydrogen gas penetration that causes blisters.
2Reliability
If EPDM is used for sealing parts, then low-temperature sealing properties are improved, but blister resistance is insufficient due to low hydrogen gas diffusion coefficient
Solution Approach 1:
The patent creates a composite rubber material by combining EBENB polymer chains with specific molecular structure characteristics. The composite structure includes saturated main chains providing low-temperature flexibility and controlled unsaturation levels (iodine value 5-50) that regulate hydrogen gas diffusion. This composite material structure achieves both low-temperature sealing and blister resistance simultaneously.
3Productivity
If high pressure hydrogen gas is used for rapid filling, then the filling time is reduced to around three minutes, but the temperature of the high pressure tank increases due to adiabatic expansion
Solution Approach 1:
The patent converts the harmful effect of high-pressure hydrogen gas (which causes blisters due to rapid diffusion) into a beneficial effect. By controlling the rubber composition to achieve optimal hydrogen gas diffusion coefficient, the patent allows controlled hydrogen diffusion that prevents blister formation while maintaining the ability to withstand high-pressure rapid filling operations. The material transforms the potential harm of hydrogen penetration into a protective mechanism where controlled diffusion prevents pressure buildup and blister formation.
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 EBENB-based rubber composition achieves superior low-temperature sealing and blister resistance, reducing production costs and improving the durability of sealing parts for high-pressure hydrogen apparatuses, while maintaining equivalent gas barrier properties and sealing durability compared to EPDM-based compositions.
Implementation Method 1
When a sealing part is brought into contact with a high pressure hydrogen gas, a little amount of the hydrogen gas permeates the inner part the sealing part. In cases where the hydrogen gas rapidly diffuse in the inner part of the sealing part (i.e., the diffusion coefficient is large), rubber destruction is less likely to occur.
Implementation Method 2
the temperature of the high pressure tank carried on a vehicle increases due to adiabatic expansion of the gas
Data Source
AI summary
It is an object of the present invention to provide a rubber composition, in particular, suitable for producing a sealing part for a high pressure hydrogen apparatus having excellent low temperature sealing properties and blister resistance, and the sealing part for a high pressure hydrogen apparatus obtained by using the rubber composition. A rubber composition comprising an ethylene/butene/ethylidene norbornene terpolymer (EBENB), the rubber composition being for use in producing a sealing part for a high pressure hydrogen apparatus.