Two-Part Epoxy Adhesive Rapid Curing Toughening
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Solution Overview
Problem
Current 2K epoxy adhesives used in repair settings have longer curing times and reduced strength, lacking rapid strength build-up and dynamic toughness, which is essential for structural repairs, and adding low molecular weight additives to speed up curing often increases brittleness and reduces dynamic strength.
Innovation Solution
Incorporating a reactive blocked polyurethane-prepolymer in both the epoxy resin and hardener compositions of a 2K epoxy adhesive, with specific weight percentages of reactive tougheners, curing accelerators, polymeric amines, and low molecular weight amines, to achieve rapid curing and high dynamic impact peel strengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If low molecular weight additives are added to speed up curing, then curing time is reduced, but brittleness increases and dynamic strength decreases
Solution Approach 1:
The patent changes the molecular weight parameter of the amine hardener from conventional high molecular weight to low molecular weight (50-500 g/mol), which accelerates the curing reaction rate and reduces curing time while maintaining adequate dynamic strength through optimized composition ratios
Solution Approach 2:
The patent creates a composite hardener system combining low molecular weight amine (for rapid curing) with polymeric amine or amide (for toughness and dynamic strength), achieving both fast curing and high dynamic performance through synergistic material combination
2Strength
If reactive tougheners are added to improve dynamic strength, then toughness increases, but curing time increases
Solution Approach 1:
The patent optimizes the molecular weight parameter of the amine hardener to a specific range (50-500 g/mol) that provides sufficiently high reactivity to cure rapidly even in the presence of reactive tougheners, while also controlling the amount of polymeric amine/amide to balance toughness and cure speed
Solution Approach 2:
The patent uses a composite approach by combining low molecular weight amine (fast curing) with polymeric amine/amide (toughening) in specific ratios, creating a hardener system that simultaneously achieves rapid curing and high dynamic strength without the trade-off present in conventional formulations
3Strength
If polymeric amine or amide is added to reduce brittleness, then toughness improves, but curing time increases
Solution Approach 1:
The patent changes the molecular weight and structure parameters of the hardener components, using low molecular weight amine as the primary curing agent for speed, and limiting polymeric amine/amide to 5-30 phr to provide toughness enhancement without significantly retarding the cure rate
Solution Approach 2:
The patent creates a multi-component hardener system where low molecular weight amine provides rapid initial curing, and polymeric amine/amide provides subsequent toughness development, achieving both fast set time and high final toughness through controlled material composition
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 results in significantly increased strength build-up and rapid curing times, with set times less than 60 minutes and high lap shear and impact peel strengths, addressing the limitations of existing 2K epoxy adhesives in repair settings.
Implementation Method 1
a low molecular weight amine in the amount of 10 to 25 wt% of composition B
Implementation Method 2
Incorporating a reactive blocked polyurethane-prepolymer in both the epoxy resin and hardener compositions
Data Source
AI summary
A 2K epoxy adhesive is provided that has rapid cure time and good strength characteristics. Both the epoxy resin composition and the hardener composition of the 2K epoxy comprise a reactive toughener. Such adhesives are useful in the manufacture and/or repair of large machinery (e.g., automobiles), and are useful for bonding like or unlike materials, such as metal and composites (e.g., carbon fiber or glass fiber composites).