Fuel Cell Sealing Composition Without Silica Elution Cracking
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Solution Overview
Problem
Existing sealing members for fuel cells face challenges in compression crack resistance, and the use of silica as a material can lead to silica elution, affecting performance and stability, while balancing mechanical strength and elongation properties is difficult.
Innovation Solution
A radically curable sealing member composed of a crosslinked body containing a polyisobutylene polymer with a (meth)acryloyl group, a polyfunctional (meth)acrylic monomer with 5 or more functional groups, a monofunctional (meth)acrylic monomer, and a radical polymerization initiator, without silica, to enhance compression crack resistance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silica is added to the sealing member material to improve compression crack resistance, then compression crack resistance is improved, but silica elution occurs over time affecting performance and stability
Solution Approach 1:
The patent removes silica from the sealing member composition entirely, extracting the problematic component that causes elution while maintaining compression crack resistance through alternative means (polymer blend composition and crosslinking)
Solution Approach 2:
The patent uses a composite polymer system combining polyisobutylene polymer with polyfunctional acrylic monomers to achieve both mechanical strength and stability without silica, creating a new composite material system that eliminates the elution problem while maintaining performance
2Reliability
If the sealing member is highly compressed (50% compression ratio) to seal the fuel cell, then sealing performance is improved, but compression crack resistance becomes critical and difficult to maintain
Solution Approach 1:
The patent changes the material parameters of the sealing member by using a specific polymer blend ratio and crosslinking degree, enabling the material to maintain adequate compression crack resistance even under high compression conditions (50% compression ratio) required for fuel cell sealing
3Strength
If mechanical strength is increased to improve compression crack resistance, then compression crack resistance is improved, but elongation properties deteriorate
Solution Approach 1:
The patent creates a composite polymer system where polyisobutylene polymer provides elasticity and elongation properties, while polyfunctional acrylic monomers provide crosslinking for strength, achieving a balance where both compression crack resistance and elongation properties are maintained simultaneously
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 sealing member exhibits excellent compression crack resistance, maintains mechanical strength and elongation properties, and ensures stability without silica elution, improving productivity and quality.
Implementation Method 1
a radically curable sealing member which includes a crosslinked body of a radically curable composition
Data Source
AI summary
A radically curable sealing member for fuel cells is formed of a crosslinked body of a radically curable composition which contains the components (A) to (D) described below, with the content of the component (B) being 5 parts by mass to 20 parts by mass with respect to 100 parts by mass of the component (A): (A) a polyisobutylene polymer having a (meth)acryloyl group at a molecular chain end; (B) a polyfunctional (meth)acrylic monomer having 5 or more functional groups; (C) a monofunctional (meth)acrylic monomer; and (D) a radical polymerization initiator.