Water-Based Epoxy Primer with Graphene for Adhesive Bonding
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Solution Overview
Problem
Conventional bonding methods in aerospace and automotive industries face challenges with adhesive strength degradation due to hydrolysis of metal surfaces during inactive periods, and existing non-chromated corrosion inhibitors fail to provide adequate durability and performance in harsh environmental conditions.
Innovation Solution
A water-based bonding primer composition containing epoxy resins, curing agents, silane compounds, and low amounts of graphene or graphite nano-sized platelets, which forms a synergistic barrier against corrosion without compromising mechanical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cleaning methods are used to prepare metal surfaces for bonding, then adhesive strength is improved, but the surface becomes vulnerable to hydrolysis and corrosion during inactive periods
Solution Approach 1:
The patent applies a primer composition to the metal surface immediately after cleaning, before bonding. This preliminary action creates a protective layer that prevents hydrolysis and corrosion during inactive periods, while also providing a base for subsequent adhesive bonding. The primer contains corrosion inhibitors and adhesion promoters that are applied in advance to prepare the surface for both corrosion resistance and bonding strength.
Solution Approach 2:
The primer composition is a composite material containing multiple functional components: corrosion inhibitors (such as zinc phosphate, molybdenum zinc phosphate, calcium borosilicate), adhesion promoters, and resin matrices. This composite structure provides both corrosion protection and bonding capability simultaneously, resolving the contradiction between adhesive strength and corrosion resistance.
2Reliability
If chromated primers are used to protect metals from corrosion, then corrosion resistance is improved, but environmental harm increases due to chromium restrictions
Solution Approach 1:
The patent removes harmful chromium-based corrosion inhibitors from the primer composition and replaces them with environmentally friendly alternatives such as zinc phosphate, molybdenum zinc phosphate, and calcium borosilicate. This extraction of the harmful component while retaining the corrosion protection function resolves the contradiction between corrosion resistance and environmental harm.
Solution Approach 2:
The patent changes the chemical composition parameters of the corrosion inhibitors from chromium-based to non-chromium-based compounds. This parameter change maintains the corrosion inhibition mechanism while eliminating the environmental toxicity associated with chromium, thus resolving the contradiction between effective corrosion protection and environmental safety.
3Ease of manufacture
If passive corrosion inhibitors are used in the primer, then ease of manufacture is improved, but durability and performance in harsh environments deteriorate
Solution Approach 1:
The patent creates a composite primer system that combines passive corrosion inhibitors with active corrosion protection mechanisms. The formulation includes multiple corrosion inhibitor types and adhesion promoters work synergistically to provide both ease of manufacture and superior durability in harsh environments, resolving the contradiction between simplicity and performance.
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 primer composition significantly enhances corrosion resistance and mechanical properties, maintaining adhesive strength and toughness even in extreme conditions, as demonstrated by improved performance in scribe corrosion and floating roller peel tests.
Implementation Method 1
Failure of these joints often starts with diffusion of water through the adhesive followed by corrosion of the underlying metal structure. The carbon-based material is selected from graphene, graphite... a low amount of carbon-based material in particulate form
Implementation Method 2
one or more epoxy resins, one or more curing agents... the bonding primer composition is a water-based (or aqueous) dispersion containing water, one or more epoxy resins, one or more curing agents
Implementation Method 3
a silane compound... (iii) a silane compound
Data Source
Figure 1A~2
AI summary
A water-based bonding primer composition and a method of applying the same onto a metallic surface prior to adhesive bonding. The bonding primer composition is a water- based dispersion containing water, one or more epoxy resins, at least one curing agent, a silane compound, a low amount of a carbon-based material in particulate form, and optional additives. The carbon-based material is selected from graphene, graphene oxide(GO), graphite, carbon with various structures in micron-scale or nanoscale size, and combination thereof.