Toughened Epoxy Adhesive for Vehicle Assembly Impact Peel Strength
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Solution Overview
Problem
Epoxy-based adhesive compositions used in vehicle assembly have low impact peel strength at low temperatures, failing to meet safety requirements and showing limited effectiveness on high-strength metals across varying temperature conditions.
Innovation Solution
A composition comprising a first epoxy resin, a second epoxy resin modified with acrylonitrile-butadiene rubber, and a toughener, with the total weight percentage of the latter two exceeding 30% and a weight ratio greater than 1:1, enhancing impact peel strength and mechanical properties at both room and low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additional flexibilizers and/or tougheners are added to the epoxy adhesive composition to improve dynamic strength, then impact peel strength is improved, but storage stability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the toughener by selecting specific compounds with defined molecular weights and functional groups. The toughener comprises a polyol and a polyisocyanate in specific weight ratios (0.5-5 wt% polyol, 0.5-5 wt% polyisocyanate), creating a controlled polyurethane polymer that improves impact strength while maintaining storage stability through optimized composition parameters.
Solution Approach 2:
The patent creates a composite adhesive system combining epoxy resin, curing agent, accelerator, and a specifically designed toughener comprising polyol and polyisocyanate. This multi-component composite formulation achieves synergistic effects where the toughener enhances impact peel strength while the controlled composition maintains storage stability, resolving the contradiction between these two properties.
2Strength
If conventional epoxy adhesive compositions are used to assemble high strength metal parts, then static strength is achieved, but impact behavior at extreme temperatures deteriorates
Solution Approach 1:
The patent modifies the thermal parameters of the adhesive by incorporating a toughener with specific glass transition temperature characteristics. The polyol and polyisocyanate components create a polyurethane network that maintains flexibility and impact resistance at extreme temperatures while preserving the high static strength required for high strength metal assembly, thus improving reliability across temperature ranges.
3Ease of manufacture
If known epoxy adhesive compositions are used for vehicle assembly, then assembly is enabled, but safety requirements in crash tests are not fully met due to low impact peel strength at low temperatures
Solution Approach 1:
The patent develops a specialized composite adhesive formulation tailored for vehicle assembly safety. The toughener comprising polyol and polyisocyanate in optimized ratios creates a polyurethane-enhanced epoxy adhesive that provides both assembly capability and crash safety performance, meeting stringent safety requirements in crash tests while maintaining ease of manufacture.
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 resulting adhesive achieves high impact peel strength, crash resistance, and excellent adhesion on high-strength metals, maintaining strength values even after artificial aging, thus meeting stringent safety and mechanical requirements.
Implementation Method 1
the epoxy groups of the epoxy resin react with the curing agent linking the epoxy resin compounds by a polyaddition reaction to obtain a cured product
Implementation Method 2
a second epoxy resin modified with an acrylonitrile-butadiene rubber, the latter comprising on average less than about 25 weight percent acrylonitrile
Implementation Method 3
a toughener, the total amount of component b) and component c) being more than about 30 percent based on the total weight of the composition
Data Source
AI summary
The invention relates to an epoxy adhesive composition comprisinga) a first epoxy resin,b) a second epoxy resin modified with an acrylonitrile-butadiene rubber, the latter comprising on average less than about 25 weight percent acrylonitrile, andc) a toughener.The total amount of component b) and component c) is higher than about 30 percent based on the total weight of the composition, and the weight ratio of component c) to component b) is greater than about 1:1.The invention further relates to the use of said epoxy adhesive composition for the assembly of parts of a vehicle. It also relates to a vehicle, parts of which are assembled by said epoxy adhesive composition.