Fuel Cell Sealing Member Bonding via Low-Temp Hydrosilicone Crosslinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for bonding ethylene propylene diene rubber (EPDM) with a modified polypropylene (PP) base material for fuel cell sealing parts face challenges such as the need for adhesive application, positioning difficulties, and poor production efficiency, especially due to the melting of the modified PP during vulcanization at high temperatures.
Innovation Solution
A method involving hydrosilicone crosslinking of EPDM, where vulcanization is performed at a temperature lower than the melting point of modified PP, allowing bonding without the need for adhesives and simplifying the positioning process, using a rubber composition with an ethylene/α-olefin/5-vinyl-2-norbornene random copolymer, hydrosilicone compound, and a catalyst, which controls the vulcanization start temperature to ensure strong bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vulcanization bonding is performed at high temperature (150-160°C), then the EPDM rubber achieves proper vulcanization, but the modified PP base material melts and deforms
Solution Approach 1:
The patent changes the vulcanization temperature parameter from the conventional 150-160°C to a lower range of 90-130°C, which is below the melting point of modified PP (140°C). This parameter change allows vulcanization to proceed while preventing the base material from melting, resolving the contradiction between achieving proper rubber vulcanization and maintaining base material integrity
Solution Approach 2:
The patent introduces a silane crosslinking system as an intermediary mechanism. Instead of relying on traditional sulfur vulcanization that requires high temperatures, the silane system enables crosslinking at lower temperatures through a different chemical pathway, allowing vulcanization to occur without melting the PP base material
2Strength
If adhesive bonding is used to bond EPDM with modified PP, then bonding is achieved, but the process complexity increases and production efficiency decreases
Solution Approach 1:
The patent merges the vulcanization process with the bonding process into a single simultaneous operation. The EPDM rubber is vulcanized and bonded to the modified PP base material in the same heating step, eliminating the need for separate adhesive application and curing steps. This integration improves production efficiency while maintaining bonding strength
Solution Approach 2:
The patent extracts the adhesive bonding step from the overall process and replaces it with direct vulcanization bonding. By removing the adhesive intermediary and using the vulcanization reaction itself to create the bond, the process is simplified and production efficiency is improved while still achieving strong bonding
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
This approach enables the production of a sealing member for fuel cells with enhanced peeling strength and improved bonding efficiency, eliminating the need for adhesive application and simplifying the bonding process, while preventing the modified PP from melting during vulcanization.
Implementation Method 1
a vulcanization start temperature in hydrosilicone crosslinking of EPDM is lower than 90° C. However, 90° C. is a temperature during kneading, for example, and vulcanization is generally performed at a vulcanization temperature of 150° C. to 160° C.
Data Source
AI summary
A method of producing a sealing member for a fuel cell includes: setting a base material made of a modified polypropylene in a mold; bringing a hydrosilicone crosslinked ethylene/α-olefin/non-conjugated diene copolymer into contact with the base material and performing molding in the mold; and vulcanizing the hydrosilicone crosslinked ethylene/α-olefin/non-conjugated diene copolymer and at the same time, bonding the hydrosilicone crosslinked ethylene/α-olefin/non-conjugated diene copolymer and the base material by vulcanization, in the mold with a molding temperature set to a temperature that is higher than a vulcanization start temperature of the hydrosilicone crosslinked ethylene/α-olefin/non-conjugated diene copolymer and lower than a melting point of the modified polypropylene.