Two-Component Epoxy Premix for Structural Foam Injection Molding
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Solution Overview
Problem
Conventional expandable and curable epoxy resin mixtures for structural foams in metallic hollow structures face challenges with high viscosity and tackiness, limiting their use in injection molding and requiring costly modifications to equipment, which results in poor quality and high technical effort in production.
Innovation Solution
A two-component premix system is developed, where Component A contains isocyanate and Component B contains diol or polyol, along with epoxy prepolymers and heat-activatable hardeners and blowing agents, allowing for pre-curing at room temperature or above, reducing viscosity and enabling easier processing and improved storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional expandable and curable epoxy resin mixtures are used for structural foams, then structural integrity and expandability are maintained, but viscosity is high and tackiness is excessive, limiting use in injection molding
Solution Approach 1:
The epoxy resin mixture is divided into two separate components: Component A containing epoxy prepolymers and Component B containing polyol and isocyanate. This segmentation allows each component to be optimized independently, resulting in lower viscosity and reduced tackiness while maintaining the ability to form structural foams with high structural integrity when mixed and cured.
2Ease of manufacture
If conventional epoxy resin mixtures are used, then structural strength is achieved, but costly modifications to injection molding equipment are required
Solution Approach 1:
The invention changes the physical and chemical parameters of the epoxy system by using prepolymers with controlled molecular weight and functionality, along with specific polyol and isocyanate combinations. This results in a two-component system with optimized viscosity and reactivity, enabling standard injection molding equipment to be used without modifications while producing high-quality structural foam parts.
3Manufacturing precision
If high viscosity epoxy mixtures are used, then structural foam integrity is maintained, but production requires high technical effort and results in poor quality
Solution Approach 1:
The epoxy prepolymers are pre-synthesized with controlled molecular weight and functionality before use in the injection molding process. This preliminary preparation ensures that the components have optimal viscosity and reactivity characteristics, reducing the technical effort required during production and enabling consistent high-quality part manufacturing using standard equipment.
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 allows for the production of dimensionally stable moldings that can be easily introduced into molds, reducing production costs and improving the quality of injection-molded parts by lowering viscosity and minimizing tackiness, while maintaining structural integrity and expandability.
Implementation Method 1
Pre-curing is based on the formation of a polyurethane from an alcohol component in the one component and from an isocyanate component in the other component of the premix
Implementation Method 2
Final curing to form a structural foam takes place later on heating, based on the heat-induced curing reaction of epoxy resin prepolymers
Implementation Method 3
at least one of components A and B containing a heat-activatable blowing agent
Data Source
AI summary
A two-component premix for preparing a heat-expandable and heat-curable epoxy-based material, comprises an isocyanate, a diol or polyol, an epoxy prepolymer, a heat-activatable hardener for epoxy prepolymers, and a heat-activatable blowing agent.