Photocurable Sealing Material for Fast Cure and Low Compression Set
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Solution Overview
Problem
Conventional photocurable resin compositions used in CIPGs for fuel cells fail to maintain low compression set under stringent conditions of high compression rates and elevated temperatures for extended periods, necessitating a method that can cure quickly while ensuring durability and sag resistance.
Innovation Solution
A method involving irradiation of a photocurable resin composition with specific wavelengths and ratios of photoradical polymerization initiators, combined with specific components such as urethane (meth)acrylates and monofunctional (meth)acrylates, to achieve rapid curing and low compression set under high compression rates and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photocurable resin compositions are used for CIPG sealing in fuel cells, then the sealing material can be applied and cured, but the compression set increases excessively under high temperature and high compression rate conditions
Solution Approach 1:
The patent changes the chemical composition parameters of the photocurable resin by incorporating specific components: a polyfunctional (meth)acrylate component, a monofunctional (meth)acrylate component with specific glass transition temperature, and a photopolymerization initiator. These parameter changes in material composition result in a cured product that maintains low compression set (35% or less) under high temperature (140°C) and high compression rate conditions while achieving excellent sag resistance.
2Reliability
If conventional photocurable resin compositions are used, then the sealing material can be cured, but the curing time is excessively long
Solution Approach 1:
The patent optimizes the photopolymerization system by selecting specific photopolymerization initiators and adjusting their concentration (0.01-5 parts by mass based on total (meth)acrylate components). This parameter optimization enables the resin to cure completely within 10 seconds or less under UV irradiation, achieving both rapid curing and reliable sealing performance.
3Measurement precision
If the compression rate is increased to 50% for stringent testing, then the sag resistance can be evaluated more stringently, but the compression set becomes excessively large
Solution Approach 1:
The patent creates a composite resin system combining polyfunctional (meth)acrylate components (providing crosslinking and structural integrity) with monofunctional (meth)acrylate components (providing flexibility and low glass transition temperature). This composite material structure enables the sealing material to withstand 50% compression rate testing while maintaining compression set at 35% or less, achieving both rigorous evaluation capability and excellent mechanical performance.
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 method produces a sealing material with a compression set of 35% or less at 50% compression rate and 140°C for 72 hours, enhancing durability and productivity.
Implementation Method 1
a curable resin composition which is curable by a photoradical polymerization upon being irradiated with light
Implementation Method 2
a photoradical polymerization initiator having a molar absorption coefficient of 10 L/(mol·cm) or more at the wavelength (I)
Data Source
AI summary
A method of producing a sealing material according to the present disclosure includes the step of irradiating a photocurable resin composition with light (a) including at least one wavelength (I) from 395 nm to 435 nm, and then irradiating the composition with light (b) including at least one wavelength (II) from 200 nm to 385 nm. In the light (a), the irradiation energy in the wavelength range of from 200 nm to 385 nm is equal to or less than 0.2 times the irradiation energy in the wavelength range of from 395 nm to 435 nm. The photocurable resin composition includes a specific component (A), a specific component (B), a specific component (C) and a specific component (D), in specific proportions.