Polyurea Oligomer Curing Agent for Epoxy Fracture Toughness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional curing agents for epoxy resins often increase viscosity and require additional processing steps to enhance fracture toughness, which complicates production and increases costs, while high viscosity toughening agents like CTBN are not ideal for processability.
Innovation Solution
A partially reacted product of an isocyanate and amine, forming polyurea oligomers, is used as a curing agent that does not increase viscosity and is soluble in the amine component, forming a network within the cured epoxy resin to improve fracture toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a dispersed phase is added to the epoxy resin to improve fracture toughness, then the fracture toughness is improved, but the viscosity of the resin increases and additional processing steps are required
Solution Approach 1:
The patent combines the toughening function with the curing agent function into a single component. The polyurea oligomer serves both as a curing agent for the epoxy resin and as a toughening agent, eliminating the need for separate dispersed phase additions and reducing processing complexity while maintaining improved fracture toughness
Solution Approach 2:
The curing agent is designed to perform multiple functions simultaneously: it cures the epoxy resin and provides fracture toughness enhancement. This multi-functional curing agent eliminates the need for separate toughening agents and their associated processing steps
2Strength
If a dispersed phase is added to the epoxy resin to improve fracture toughness, then the fracture toughness is improved, but the viscosity of the resin increases
Solution Approach 1:
The patent combines the toughening function with the curing agent function into a single component. The polyurea oligomer serves both as a curing agent for the epoxy resin and as a toughening agent, eliminating the need for separate dispersed phase additions and reducing processing complexity while maintaining improved fracture toughness
Solution Approach 2:
The patent changes the chemical structure and properties of the curing agent to achieve low viscosity while maintaining toughening capability. The polyurea oligomer is specifically designed with molecular characteristics that provide fracture toughness enhancement without the viscosity increase associated with conventional dispersed phase toughening agents
3Strength
If high viscosity toughening agents like CTBN are used to improve fracture toughness, then the fracture toughness is improved, but the processability is reduced
Solution Approach 1:
The patent changes the chemical structure and properties of the curing agent to achieve low viscosity while maintaining toughening capability. The polyurea oligomer is specifically designed with molecular characteristics that provide fracture toughness enhancement without the viscosity increase associated with conventional dispersed phase toughening agents
Solution Approach 2:
The curing agent is designed to perform multiple functions simultaneously: it cures the epoxy resin and provides fracture toughness enhancement. This multi-functional curing agent eliminates the need for separate toughening agents and their associated processing steps
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 provides epoxy resins with enhanced fracture toughness without additional processing steps or increased viscosity, maintaining improved processability and mechanical properties, such as resistance to crack propagation and thermal stability.
Implementation Method 1
when the curing agent reacts with epoxy resin, oligomers present in curing agent form a network with micro domains or phases within the cured epoxy resin that imparts ductility thereby increasing the fracture toughness of the cured epoxy
Implementation Method 2
The at least partially reacted product does not increase the viscosity of the curing agent and is at least partially soluble in the amine component of the curing agent
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The disclosure relates toat least one partially reacted product of an isocyanate and an amine (e.g., a reaction product comprising at least one adducted compound). The reaction product comprises polyurea oligomers. The reaction product can be combined with at least one amine in order to formulate a curing agent for epoxy resins wherein the cured epoxy resin has enhanced fracture toughness. The at least partially reacted product does not increase the viscosity of the curing agent and is at least partially soluble in the amine component of the curing agent.