Thermosetting Epoxy Adhesion on Metal Substrates
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Solution Overview
Problem
Existing thermally expandable thermosetting epoxy resin compositions lack sufficient adhesion, particularly on metal substrates, which is crucial for reinforcing hollow structures and structural foams.
Innovation Solution
A one-component thermosetting epoxy resin composition is developed, comprising 20-55 weight% epoxy resin with multiple epoxide groups, 1-6 weight% latent hardener, 0-3 weight% accelerator, 10-50 weight% impact modifier, 0.01-5 weight% blowing agent, and 2-35 weight% fibrous anhydrous magnesium oxysulfate, which enhances adhesion and mechanical properties when cured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermally expandable thermosetting epoxy resin composition is used to reinforce hollow structures, then volume expansion and structural reinforcement are achieved, but adhesion on metal substrates is insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the epoxy resin system by incorporating specific adhesion promoters and optimizing the ratio of epoxy resin to curing agent. This changes the chemical properties of the base resin to improve its affinity for metal substrates, directly addressing the adhesion deficiency while maintaining the thermally expandable characteristics
Solution Approach 2:
The patent creates a composite epoxy composition by combining multiple components: base epoxy resin, adhesion promoters, curing agents, and optional fillers. This composite approach integrates materials with complementary properties, where the adhesion promoter specifically enhances metal substrate bonding while the other components maintain structural reinforcement and expansion capabilities
2Weight of moving object
If hollow parts are used for weight reduction, then weight is reduced, but mechanical stress resistance is compromised
Solution Approach 1:
The epoxy resin composition is applied to hollow structures in an uncured state before final assembly, allowing it to conform to the hollow geometry. Upon thermal curing, the material hardens and expands to create internal reinforcement, preliminarily strengthening the structure before it undergoes mechanical stress during vehicle operation
Solution Approach 2:
The patent utilizes the phase transition of the thermally expandable epoxy resin from a soft, uncured state to a hardened, cured state. This phase change occurs when the resin is exposed to heat during curing, transforming the material properties to provide mechanical strength while maintaining the hollow structure's weight advantages
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 composition exhibits improved adhesion and mechanical properties, including increased lap shear values and enhanced failure mode, particularly on metal substrates, while maintaining volume expansion properties.
Implementation Method 1
improved adhesion, especially on metal substrates
Implementation Method 2
thermally expandable one-component thermosetting epoxy resin composition
Implementation Method 3
one-component thermosetting epoxy composition
Data Source
AI summary
The present invention relates to a one-component thermosetting epoxy resin composition, comprising at least one epoxy resin A having on average more than one epoxide group per molecule, at least one latent hardener B for epoxy resins, at least one impact modifier D, at least one physical or chemical blowing agent E and fibrous anhydrous magnesium oxysulfate MOS. The invention provides thermally expandable epoxy resin compositions with improved adhesion, especially on metal substrates.