Epoxy Curing Blend for Wind Turbine Blade Fabrication
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Solution Overview
Problem
Existing epoxy resin curing agents often cause a sharp increase in viscosity, leading to reduced flowability and prolonged cycle times in composite fabrication, which is undesirable for maintaining processing efficiency and producing high-quality composite articles.
Innovation Solution
A curable composition comprising an epoxy resin and a curing component that includes a polyetheramine, an accelerant selected from imidazole or tertiary amines, and optionally a second amine, which is substantially free of cyclic carbonate, guanidine derivatives, and aromatic amines, allowing for extended working life and rapid curing while maintaining low viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional curing agents (amines, acid anhydrides, Lewis acids) are used to cure epoxy resins, then the epoxy resin can be converted into a cured composite article, but the viscosity increases sharply, reducing flowability and prolonging cycle times
Solution Approach 1:
The patent changes the chemical parameters of the curing agent system by using a specific blend of polyetheramine (50-90 wt%), cycloaliphatic amine (5-40 wt%), and imidazole accelerator (0.1-5 wt%). This parameter optimization resolves the contradiction by achieving rapid curing (reduced cycle time) while controlling viscosity increase, unlike conventional single-agent systems that cause sharp viscosity rises
Solution Approach 2:
The patent applies composite materials principle by creating a multi-component curing agent system rather than using a single curing agent. The synergistic combination of polyetheramine, cycloaliphatic amine, and imidazole accelerator produces a curing system that maintains low viscosity during processing while achieving complete cure, thereby reducing cycle time without sacrificing curing effectiveness
2Speed
If aliphatic amines are used as curing agents, then rapid reaction with epoxy resin occurs at room temperature, but the working life becomes very short (approximately 30 minutes)
Solution Approach 1:
The patent uses polyetheramine as the primary curing agent which reacts more slowly than aliphatic amines, providing a preliminary extended working life. The imidazole accelerator is then added to trigger and accelerate the curing reaction at the appropriate time, thus achieving both extended working life and rapid curing reaction
Solution Approach 2:
The imidazole accelerator acts as an intermediary substance that mediates between the slow-reacting polyetheramine/cycloaliphatic amine system and the epoxy resin. It triggers and accelerates the curing reaction without being consumed in the main reaction, thereby enabling rapid curing while maintaining extended working life
3Duration of action of moving object
If cycloaliphatic amines are used as curing agents, then the working life is extended compared to aliphatic amines, but the reaction rate decreases and mild heat is required for curing
Solution Approach 1:
The imidazole accelerator serves as an intermediary that triggers and accelerates the curing reaction of cycloaliphatic amines with epoxy resin. This allows the system to maintain the extended working life characteristic of cycloaliphatic amines while achieving rapid curing rates through the catalytic action of imidazole, eliminating the need for mild heat
4Speed
If Lewis acids such as boron trifluoride are used as curing agents, then rapid and highly exothermic polymerization occurs, but blocking techniques must be used to halt the reaction
Solution Approach 1:
The patent changes the chemical parameters by using organic amine-based curing agents instead of inorganic Lewis acids like boron trifluoride. This parameter change achieves rapid and exothermic polymerization through the amine-epoxy reaction mechanism while avoiding the uncontrolled reaction and blocking issues associated with Lewis acids, thereby simplifying the processing procedure
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 solution extends the working life of the curable composition, enables rapid curing with excellent thermal and mechanical properties, and is suitable for composite fabrication processes such as filament winding and resin infusion, particularly for applications like wind turbine blades.
Implementation Method 1
Curing agents function by reacting with or causing the reaction of the epoxide or hydroxyl groups in the epoxy resin
Implementation Method 2
All of the amines, as well as the acid anhydrides, react with the epoxy ring by nucleophilic addition to the terminal carbon atom of the epoxide
Implementation Method 3
an accelerant selected from an imidazole and/or a tertiary amine
Implementation Method 4
convert epoxy resins into useful products, they must be 'cured' or cross-linked by chemical reaction into a three-dimensional, infusible network
Data Source
AI summary
The present disclosure provides a curable composition that includes an epoxy resin and a curing component comprising a blend of at least two amines. The curable composition may be combined with reinforced fibers and cured to form a composite article which can be used in various applications, such as in wind turbine blades.