Epoxy Resin Composition Balancing Curing Speed and Storage Stability
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Solution Overview
Problem
Conventional epoxy resin compositions for fiber-reinforced composite materials face challenges in achieving a balance between fast curability, storage stability, and handleability during the preforming step, with existing solutions either prioritizing one aspect over others or failing to provide simultaneous high performance in all areas.
Innovation Solution
An epoxy resin composition comprising epoxy resin, dicyandiamide, aromatic urea, and borate ester, specifically formulated to meet certain ratios and requirements that enhance both fast curability and storage stability, while maintaining high handleability and demolding properties, is developed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an epoxy resin composition with increased reactivity is used to achieve fast curing, then curing time is shortened, but storage stability deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the molecular weight distribution and chemical structure parameters of the epoxy resin to achieve optimal balance between reactivity and stability. Specifically, it uses epoxy resins with controlled glass transition temperatures and specific hydroxyl value ranges to optimize both curing speed and storage stability simultaneously
Solution Approach 2:
The patent employs composite materials by combining epoxy resin with specific curing agents and additives in predetermined ratios. The formulation includes epoxy resin, curing agent, and optional additives in specific proportions to create a composite system that achieves both fast curing and high storage stability, resolving the contradiction between these two properties
2Productivity
If aromatic urea with high activity is used to achieve fast curability, then curing rate increases, but handleability deteriorates due to premature curing during storage
Solution Approach 1:
The patent applies parameter changes by selecting aromatic urea with specific activity levels and molecular weights, and by controlling the ratio of aromatic urea to other curing agents. This parameter optimization ensures fast curing when needed while preventing premature curing during storage, thereby maintaining handleability
Solution Approach 2:
The patent uses an intermediary approach by introducing a blocking agent or controlled-release curing mechanism that prevents premature reaction during storage but allows fast curing when activated. This intermediary substance mediates between the high reactivity needed for fast curing and the stability needed for handleability
3Stability of the object's composition
If epoxy resin composition is formulated for high storage stability, then quality changes during preforming are reduced, but curing time increases
Solution Approach 1:
The patent applies preliminary action by pre-formulating the epoxy resin composition with curing agents and additives in optimal ratios during manufacturing. This preliminary preparation ensures that the composition maintains stability during storage and transport but rapidly cures when activated during actual use, resolving the time-stability contradiction
Solution Approach 2:
The patent uses parameter changes by adjusting the molecular weight, hydroxyl value, and glass transition temperature of the epoxy resin to achieve optimal balance. These parameter optimizations enable the resin to remain stable during storage while curing rapidly when activated, eliminating the trade-off between stability and curing time
4Productivity
If fast cure type prepreg is used to reduce molding cycle time, then productivity increases, but storage stability and quality changes during preforming worsen
Solution Approach 1:
The patent employs composite materials by creating a specialized prepreg composition that combines epoxy resin with specific curing agents, additives, and fiber reinforcements in optimized ratios. This composite formulation achieves fast curing for reduced molding cycle time while maintaining storage stability through controlled reactivity and quality additives
Solution Approach 2:
The patent applies parameter changes by optimizing the molecular weight distribution, hydroxyl value, and curing agent ratios in the prepreg composition. These parameter adjustments enable the prepreg to cure rapidly during molding while remaining stable during storage and preforming operations, resolving the contradiction between productivity and stability
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 composition achieves a balance between fast curing, storage stability, and good mechanical properties, ensuring high-quality fiber-reinforced composite materials with improved appearance and demolding properties.
Implementation Method 1
epoxy resin composition comprising epoxy resin, dicyandiamide, aromatic urea, and borate ester
Data Source
AI summary
The present invention aims to provide an epoxy resin composition that is high in both fast curability and storage stability, a prepreg prepared by using the epoxy resin composition, and a fiber reinforced composite material prepared by curing the prepreg.The epoxy resin composition contains the following components [A], [B], [C], and [D] and meets the following requirements [a], [b], and [c]:[A]: epoxy resin,[B]: dicyandiamide,[C]: aromatic urea,[D]: borate ester,[a]: 0.014≤(content of component [D]/content of component [C])≤0.045,[b]: 0.9≤(number of moles of active groups in component [A]/number of moles of active hydrogen in component [B])≤1.2, and[c]: 14≤(content of component [A]/content of component [C])≤25.