UV Resistant Epoxy Structural Adhesive via Aromatic-Free Formulation
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Solution Overview
Problem
Existing structural adhesives face issues with UV resistance, sag resistance, and slow curing at room temperature, often containing hazardous peroxides and exhibiting yellowing when exposed to UV radiation.
Innovation Solution
A two-part structural adhesive system comprising part (A) with a saturated epoxy resin and a compound having at least two epoxy groups and one hydroxy group, and part (B) with a metal salt catalyst and an amine hardener, which is substantially free of aromatic epoxy resins, allowing for rapid curing at ambient temperature and providing excellent UV resistance and sag resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aromatic epoxy resins are used in structural adhesives, then bond strength is improved, but UV resistance deteriorates (yellowing occurs)
Solution Approach 1:
The patent removes aromatic epoxy resins from the adhesive formulation to eliminate the source of UV-induced yellowing, while maintaining bond strength through alternative resin components that do not contain aromatic structures
Solution Approach 2:
The patent changes the chemical composition parameters by substituting aromatic epoxy resins with alternative resin systems, fundamentally altering the molecular structure to prevent UV absorption that causes yellowing while preserving adhesive performance
2Reliability
If conventional structural adhesives are used, then bonding capability is achieved, but curing speed at room temperature deteriorates (slow cure)
Solution Approach 1:
The patent incorporates pre-formulated catalyst and hardener components in specific ratios within the adhesive system, enabling the curing reaction to proceed rapidly at room temperature without requiring external activation or heating
Solution Approach 2:
The patent modifies the curing kinetics by selecting specific hardener and catalyst combinations that lower the activation energy of the curing reaction, allowing rapid crosslinking to occur at ambient temperatures
3Reliability
If conventional structural adhesives are used, then bonding is achieved, but sag resistance deteriorates
Solution Approach 1:
The patent adjusts the rheological parameters of the adhesive by modifying viscosity and gel time through component selection, creating a formulation that maintains adequate flow for bonding while resisting sag under gravity before curing
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 adhesive system exhibits superior shear performance, rapid cure speed, and remains non-yellow when exposed to UV radiation, making it suitable for both indoor and outdoor applications with strong bond strengths ranging from 2500-4000 psi in shear.
Implementation Method 1
part (B) containing a metal salt catalyst and an amine hardener
Implementation Method 2
rapid curing at ambient temperature
Data Source
AI summary
The present disclosure relates to UV resistant multi -component structural adhesive systems that are substantially free of aromatic epoxy resins, Also provided are methods of preparing the multi-component structural adhesive systems and methods of bonding substrates together with such adhesive systems.