Thermosetting Epoxy Resin Composition for Structural Reinforcement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thermosetting epoxy resin compositions used in structural reinforcements and foams typically remain liquid or pastelike at room temperature, making them unsuitable for storage in dimensionally stable form and lacking sufficient tack for self-adhesive applications until fully cured.
Innovation Solution
A thermosetting epoxy resin composition comprising 17.5 - 30 weight% liquid epoxy resin, 1 - 5 weight% heat-activated hardener, 0 - 2 weight% accelerator, 5 - 12 weight% terminally blocked polyurethane prepolymer impact modifier, 0 - 5 weight% polyisoprene, and 5 - 10 weight% carboxyl- or epoxide-terminated acrylonitrile/butadiene copolymer, which maintains minimal shape alteration and exhibits high surface tack at room temperature, achieving high impact strength and adhesion upon full curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermosetting epoxy resin compositions are used in structural reinforcements, then high impact strength and adhesion are achieved, but the composition remains liquid or pastelike at room temperature causing dimensional instability during storage
Solution Approach 1:
The patent changes the physical state parameter of the epoxy resin composition by incorporating specific ratios of liquid epoxy resin (17.5-30 wt%) combined with solid rubber modifiers (5-20 wt%) and other additives. This parameter change enables the composition to exhibit solid-like dimensional stability at room temperature while maintaining the chemical properties necessary for high impact strength after curing.
Solution Approach 2:
The invention creates a composite material system combining liquid epoxy resin with solid rubber modifiers (polyisoprene, nitrile rubber), terminally blocked polyurethane prepolymer, and heat-activated hardener. This composite approach allows the material to exhibit both solid-like dimensional stability in the uncured state and high impact strength in the cured state, resolving the contradiction between these two properties.
2Ease of operation
If thermosetting epoxy resin compositions are used for self-adhesive mounting, then sufficient tack is required, but liquid compositions lack the necessary surface tack for self-adhesive applications
Solution Approach 1:
The patent modifies the surface properties of the epoxy resin composition by incorporating solid rubber modifiers and terminally blocked polyurethane prepolymer in specific amounts. These modifications change the surface tack parameter, enabling the composition to exhibit sufficient adhesion for self-adhesive mounting operations while remaining workable at room temperature.
Solution Approach 2:
The terminally blocked polyurethane prepolymer and solid rubber modifiers act as intermediary substances that mediate between the liquid epoxy resin and the substrate surface. These intermediaries provide the necessary surface tack for self-adhesive mounting while not interfering with the final cured properties of the epoxy resin system.
3Ease of operation
If liquid epoxy resin compositions are used, then ease of application is improved, but dimensional stability during storage and handling deteriorates
Solution Approach 1:
The patent optimizes the viscosity and physical state parameters of the epoxy resin composition by carefully controlling the ratios of liquid epoxy resin (17.5-30 wt%) to solid modifiers (5-20 wt%). This parameter optimization enables the composition to maintain ease of application similar to liquid resins while achieving sufficient dimensional stability for practical storage and handling.
Solution Approach 2:
The invention introduces local quality differences within the composition by incorporating solid rubber modifiers and terminally blocked polyurethane prepolymer that provide dimensional stability throughout the bulk material, while the liquid epoxy resin component maintains ease of application at the surface and interface regions. This local differentiation resolves the contradiction between these two properties.
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 is dimensionally stable at room temperature, self-adhesive, and suitable for reinforcing structural components, including inaccessible areas, with high impact strength and adhesion to metallic substrates, and can be easily reshaped before full curing.
Implementation Method 1
1 - 5 weight%, more particularly 2 - 4 weight%, of at least one hardener B for epoxy resins which is activated by elevated temperature
Data Source
AI summary
The present invention relates to thermosetting epoxy resin compositions which on the one hand at room temperature in the incompletely cured state exhibit extremely slight alteration in shape and on the other hand develop a high surface tack, and which, moreover, in the fully cured state are of high impact strength and at the same time exhibits high adhesion, particularly to metallic substrates. These compositions are ideally suited to the production of self-adhesive reinforcing elements.