Aqueous Epoxy Binder Composition for Fray-Resistant Fiber Preforms
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Solution Overview
Problem
Conventional binders for fiber-reinforced polymer composites are not environmentally friendly and struggle with automated laydown processes due to issues like fraying and uneven application, which affect the handling and shaping of fibrous materials in complex shapes and resin infusion processes.
Innovation Solution
A liquid binder composition comprising multifunctional epoxy resins, thermoplastic polymers, surfactants, and water, free of organic solvents, designed for dip-coating or spraying at ambient temperatures, enhancing the handling and slitting of fibrous materials while maintaining compatibility with epoxy-based resin matrices and supporting automated laydown processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional solvent-borne binders or powder binders are used, then binding function is achieved, but environmental friendliness deteriorates and handling properties worsen
Solution Approach 1:
The patent changes the fundamental parameter of binder composition from solvent-borne or powder form to an aqueous dispersion system. This substitution of the liquid carrier (water instead of organic solvents) resolves the environmental harm issue while the specific formulation of the aqueous dispersion maintains adequate viscosity and application properties for handling and shaping fibrous materials.
Solution Approach 2:
The binder is formulated as a composite aqueous dispersion containing multiple components including epoxy resins, thermoplastic polymers, and other additives. This composite structure allows the binder to simultaneously provide environmental benefits (water-based) while maintaining the complex functional requirements for binding, handling, and shaping through the synergistic combination of different material components.
2Extent of automation
If dry fibrous materials are cut and laid up manually, then complex shapes can be formed, but automation is limited due to fraying and deformation
Solution Approach 1:
The binder is applied to the fibrous materials in advance (pre-coating) before the layup and cutting operations. This preliminary binding action strengthens the fibers and edges beforehand, preventing fraying and deformation during subsequent automated cutting and handling processes, thereby enabling reliable automation.
Solution Approach 2:
The application of binder changes the physical state and mechanical properties of the fibrous material surface, creating a cohesive layer that resists fraying. This parameter change in the material properties (from loose fibers to bound structure) enables the material to withstand automated processing forces without deformation.
3Strength
If high resin content prepregs are used, then composite strength is improved, but resin waste increases and processing complexity increases
Solution Approach 1:
The resin application process is segmented into two distinct stages: (1) light preliminary impregnation during layup using the aqueous binder, and (2) complete resin infusion afterward using resin transfer molding or vacuum infusion. This segmentation allows minimal resin to be used initially (reducing waste) while ensuring complete saturation and strength through the second stage.
Solution Approach 2:
A light preliminary impregnation with binder is applied before the main resin infusion process. This preliminary action provides initial fiber cohesion and handling properties with minimal resin, allowing the bulk of the resin to be efficiently infused later under vacuum or pressure, thereby reducing overall resin waste while maintaining composite strength.
4Reliability
If binder is applied at high temperature, then binding efficiency is improved, but energy consumption increases and fiber damage risk increases
Solution Approach 1:
The binder formulation parameters are specifically adjusted to enable effective binding at lower temperatures. The aqueous dispersion composition and viscosity are optimized so that adequate binding occurs at ambient or mildly elevated temperatures, significantly reducing energy consumption compared to conventional high-temperature binder applications.
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 binder composition improves the integrity and cohesion of fibrous materials, reduces fraying, and allows for uniform application, enhancing the processing efficiency and mechanical performance of composite parts without significantly impacting their thermo-mechanical properties.
Implementation Method 1
The liquid binder composition is an aqueous dispersion containing (a) one or more multifunctional epoxy resins, (b) at least one thermoplastic polymer, (c) one or more surfactants selected from anionic surfactants, nonionic surfactants, and combination thereof, and (d) water
Implementation Method 2
one or more surfactants selected from anionic surfactants, nonionic surfactants, and combination thereof
Data Source
AI summary
A liquid binder composition for binding fibrous materials in the fabrication of resin-infusible preform is disclosed. The binder composition is an aqueous dispersion containing (a) one or more multifunctional epoxy resins, (b) at least one thermoplastic polymer, (c) one or more surfactants selected from anionic surfactants, nonionic surfactants, and combinations thereof, (d) water, and is essentially free of organic solvents. Also disclosed is an emulsification process for producing the liquid binder composition.