Two-Part Adhesive High Toughener Loading Mixability
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Solution Overview
Problem
Existing two-part epoxy adhesives face challenges in achieving high loading of core/shell toughener and solid epoxy resin while maintaining mixability, which affects the quality and consistency of the adhesive bond, particularly at high temperatures.
Innovation Solution
A two-part adhesive system is developed, where the curative part includes a reaction intermediate formed by suspending core/shell rubber nanoparticles in a liquid epoxy resin with an excess epoxy curative, and the epoxy part contains a high percentage of core/shell rubber nanoparticles and optional solid epoxy resin, allowing for higher nanoparticle loading without compromising mixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high loading of core/shell rubber nanoparticles is used, then the strength and high-temperature performance of the adhesive bond is improved, but the mixability and handling of the adhesive components deteriorates
Solution Approach 1:
The adhesive system is divided into two separate parts: Part A (epoxy resin part) containing core/shell rubber nanoparticles suspended in liquid epoxy resin, and Part B (curative part) containing the curative agent. This segmentation allows each part to be optimized independently - Part A can contain high concentrations of nanoparticles for improved strength while Part B remains fluid for easy handling and mixing. The nanoparticles are pre-dispersed in the liquid epoxy resin before use, ensuring uniform distribution without compromising the flow properties of the curative part.
2Strength
If high loading of solid epoxy resin is used, then the strength and high-temperature performance of the adhesive bond is improved, but the mixability and handling of the adhesive components deteriorates
Solution Approach 1:
The patent utilizes the physical state difference between liquid epoxy resin and solid epoxy resin to resolve the contradiction. Solid epoxy resin particles are suspended in liquid epoxy resin, creating a heterogeneous mixture that maintains the flow and mixability characteristics of the liquid phase while incorporating the strength benefits of solid resin. The liquid epoxy resin acts as a carrier medium that allows easy handling and mixing, while the suspended solid particles provide enhanced mechanical properties and high-temperature performance when cured.
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 approach enables a higher loading of core/shell rubber nanoparticles and solid epoxy resin, improving the strength and high-temperature performance of the adhesive bond, while ensuring easy mixing and handling of the adhesive components.
Implementation Method 1
a reaction intermediate which is the reaction product of a suspension of core/shell rubber nanoparticles in a liquid epoxy resin and an excess of the epoxy curative
Data Source
AI summary
A two-part adhesive is provided comprising: A) a curative part comprising: i) an epoxy curative; and ii) a reaction intermediate which is the reaction product of a suspension of core/shell rubber nanoparticles in a liquid epoxy resin and an excess of the epoxy curative; wherein the curative part comprises greater than 1.1 wt % core/shell rubber nanoparticles; and B) an epoxy part comprising: iii) a liquid epoxy resin; and iv) greater than 9.1 wt % core/shell rubber nanoparticles. In some embodiments, the epoxy part additionally comprises greater than 5.1 wt % solid epoxy resin, such as, e.g., triglycidyl ether of trisphenol-methane. In some embodiments, the sum of the wt % solid epoxy resin and the wt % core/shell rubber nanoparticles in the epoxy part is greater than 41.0%. In some embodiments, the sum of the wt % solid epoxy resin and the wt % core/shell rubber nanoparticles in the mixed adhesive is greater than 26.0%.