Epoxy Patch Adhesion to Contaminated Metallic Surfaces
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Solution Overview
Problem
Current panel stiffeners used in the automotive industry face challenges with delamination due to contamination, high pressure, and chemical baths, leading to inadequate adhesion and contamination of chemical baths, particularly when exposed to elevated temperatures and lubricants during vehicle manufacture.
Innovation Solution
A patch comprising an activatable adhesive material made of epoxy, core shell polymer dispersed in liquid epoxy, thermoplastic phenoxy, and epoxidized cashew nut shell oil, combined with a fiberglass mesh, which adheres to metallic surfaces in its green state and maintains adhesion through exposure to chemical baths, high pressure sprays, and extreme temperatures without requiring additional fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the glass transition temperature of the adhesive is increased to prevent wash-off, then adhesion resistance to chemical baths and high pressure sprays is improved, but green state adhesion is reduced
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive system by incorporating epoxy resin, polyamide resin, and rubber particles in specific proportions. This changes the rheological and thermal properties of the adhesive to achieve both high green state adhesion and wash-off resistance simultaneously, resolving the contradiction between early adhesion strength and later thermal stability.
Solution Approach 2:
The adhesive is formulated as a composite material system combining epoxy resin (for strength and adhesion), polyamide resin (for flexibility and green state bonding), and rubber particles (for toughness and wash-off resistance). This multi-component composite approach allows the adhesive to exhibit both high green state adhesion and resistance to chemical baths and high pressure sprays.
2Weight of moving object
If panel gauge is reduced to meet fuel economy requirements, then vehicle weight is reduced, but structural reinforcement needs increase
Solution Approach 1:
The patent uses a composite adhesive system combining epoxy resin, polyamide resin, and rubber particles that provides exceptional bond strength and structural reinforcement. This allows ultra-thin panels (14-18 gauge) to achieve the structural strength of thicker panels, enabling weight reduction while maintaining or improving structural integrity.
Solution Approach 2:
The adhesive is applied locally at specific panel locations (door edges, tailgate perimeters, quarter panels) where structural reinforcement is most needed. This localized application provides targeted structural support to thin-gauge panels without requiring overall panel thickening, thus maintaining weight savings while achieving necessary strength.
3Reliability
If adhesive formulation is changed to increase glass transition temperature, then resistance to chemical baths and high pressure sprays is improved, but adhesion to contaminated surfaces deteriorates
Solution Approach 1:
The patent adjusts the chemical composition parameters including the ratio of epoxy to polyamide resin, the type and amount of rubber particles, and the presence of specific functional groups. These parameter changes create an adhesive that maintains tack and adhesion to oily/contaminated surfaces while developing high wash-off resistance after curing, resolving the contradiction between initial adhesion and subsequent thermal/chemical stability.
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 provides robust adhesion to metallic surfaces, including aluminum, and withstands high heat and humidity, preventing wash-off during chemical coating treatments and maintaining adhesion even when surfaces are contaminated with oils and lubricants, thus enhancing structural reinforcement without additional fastening steps.
Implementation Method 1
core shell polymer dispersed in liquid epoxy
Implementation Method 2
an activatable adhesive material comprising an epoxy... adheres to metallic surfaces
Implementation Method 3
an activatable adhesive material comprising an epoxy... activated adhesive material
Data Source
AI summary
A device comprising an adhesive material and a fiberglass mesh located in direct planar contact with the adhesive material. The adhesive material is tacky in its green state and includes an epoxy, an epoxidized cashew nut shell oil, and at least about 20% by weight of a component containing a core shell polymer material to improve the adhesion capability to surfaces that are contaminated and/or exposed to high pressure spraying or chemical treatments, heat and humidity.