Epoxy Resin Hardener Blend for Rotor Blade Infusion
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Solution Overview
Problem
The production of large components such as rotor blades using epoxy resins faces challenges with rapid viscosity increase during curing, leading to incomplete infusion and prolonged cure times, which hinder productivity and energy efficiency.
Innovation Solution
A blend of epoxy resins with a hardener component comprising amines having a functionality of ≥2 and a compound of the formula I, where R1 to R6 are organic radicals, is used, allowing for controlled curing and reduced viscosity, enabling complete mold filling and uniform impregnation without premature curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If polyetheramines and isophoronediamine are used as hardener mixture, then cure rate and glass transition temperature are improved, but viscosity increases rapidly reducing processing time
Solution Approach 1:
The patent modifies the chemical composition parameters of the hardener system by introducing guanidine compounds with specific molecular structures (formula I) and controlling the ratio of different amine components. This changes the reaction kinetics parameters to achieve faster curing without excessive viscosity increase, allowing processing at elevated temperatures while maintaining complete mold filling capability.
Solution Approach 2:
The invention creates a composite hardening system combining multiple components: polyetheramines, isophoronediamine, and guanidine compounds (formula I). This composite approach leverages the fast curing capability of guanidine compounds while the polyetheramine matrix maintains processability, achieving both high cure rate and adequate processing time through synergistic interaction of components.
2Reliability
If stoichiometric amounts of amine hardener are used, then complete curing is achieved, but viscosity rises sharply preventing complete mold filling
Solution Approach 1:
The patent applies local quality by using guanidine compounds that provide localized fast curing activity, while the bulk polyetheramine matrix maintains uniform processability throughout the mixture. This localized acceleration ensures complete curing without causing premature gelation that would prevent mold filling, as the fast-reacting guanidine compounds are distributed throughout the system rather than concentrated.
Solution Approach 2:
The invention introduces dynamic control of the curing process by utilizing the temperature-dependent reactivity of the hardener components. At elevated temperatures during processing, the guanidine compounds remain sufficiently reactive to ensure complete curing, while the overall viscosity remains manageable due to the polyetheramine matrix. The system dynamically adapts its curing rate based on temperature conditions, allowing complete mold filling followed by complete curing.
3Ease of operation
If processing is performed at elevated temperatures, then viscosity is reduced improving flowability, but cure time is extended
Solution Approach 1:
The patent changes the thermal parameters of the curing system by formulating a hardener mixture specifically for elevated temperature processing. The guanidine compounds (formula I) are selected and dosed to maintain high reactivity at elevated temperatures, ensuring that even though the overall process occurs at higher temperatures for improved flowability, the cure time remains acceptable due to the accelerated reaction kinetics provided by the guanidine compounds.
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 blend achieves a comparable or higher cure rate at elevated temperatures, extending processing time and ensuring complete curing of large components like rotor blades, while maintaining low viscosity for efficient infusion processes.
Implementation Method 1
the amine curing of epoxy resins is utilized in a very wide variety of segments
Data Source
AI summary
The present invention provides a blend comprising one or more epoxy resins and a mixture which comprises 0.3 to 0.9 amine equivalent, per equivalent of epoxide of the epoxy resin used, of a hardener component a) and as hardener component b) a compound of the formula I, a process for preparing this blend, the use of the blend of the invention for producing cured epoxy resin, and an epoxy resin cured with the blend of the invention.