Thermally Expandable Epoxy Binder Composition for Automotive Laminates
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Solution Overview
Problem
Existing thermally curable foam compositions for vehicle components face challenges such as incomplete expansion due to irregular temperature profiles in painting ovens, high costs due to the use of hollow glass microbeads, and manufacturing difficulties with tacky surfaces that complicate handling and storage.
Innovation Solution
A thermally curable binder composition comprising liquid and solid epoxy resins, a propellant, curing agents, and mica-containing fillers, which expands by 50-300% at low temperatures, providing high compressive strength and dimensional stability without hollow glass beads, allowing for efficient injection molding and reduced surface tack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermally curable foam compositions are used in painting ovens with irregular temperature profiles, then the curing process is affected, but the expansion is incomplete due to low temperatures in certain areas
Solution Approach 1:
The patent modifies the chemical composition parameters of the foam system by selecting curing agents and catalysts that remain active at lower temperatures (60-120°C), enabling complete curing even in the colder bottom areas of painting ovens. This parameter change allows the foam to cure reliably across the irregular temperature profile without requiring uniform high temperatures.
2Quantity of substance
If hollow glass microbeads are used as fillers to achieve high expansion, then the degree of expansion is sufficient, but the manufacturing costs increase significantly
Solution Approach 1:
The patent replaces expensive hollow glass microbeads with cheaper organic expandable beads or gas-generating systems that provide equivalent or superior expansion (50-300%) at lower cost. These alternative expandable agents achieve the required volume increase without the high material costs of glass beads, making the manufacturing process more economically viable.
3Volume of stationary object
If the composition uses conventional fillers and curing agents, then the expansion capability is achieved, but the surface becomes tacky complicating handling and storage
Solution Approach 1:
The patent adjusts the curing agent selection and formulation parameters to achieve non-tacky surfaces after curing. By selecting specific curing agents that produce crosslinked networks without residual tackiness, and by optimizing the curing temperature and time parameters, the foam achieves complete curing with a dry, non-sticky surface that is easy to handle and store.
4Volume of stationary object
If the foam composition is designed for high expansion at low temperatures, then expansion is achieved in painting ovens, but the curing completeness may be compromised
Solution Approach 1:
The patent introduces catalysts as intermediary substances that lower the activation energy required for curing reactions, enabling complete curing to occur at the lower temperatures (60-120°C) necessary for expansion. The catalyst acts as a mediator that facilitates both expansion and curing processes under the same low-temperature conditions, resolving the conflict between achieving expansion and ensuring curing completeness.
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 enables the production of lightweight, dimensionally stable, and non-tacky moldings that can withstand temperatures up to 50°C, facilitating cost-effective and reliable manufacturing, and maintaining adhesion properties over time, even with moisture and heat exposure.
Implementation Method 1
thermally expandable mouldings from heat curable binder compositions... which exhibit a high degree of expansion
Implementation Method 2
thermally curable binder composition comprising liquid and solid epoxy resins, a propellant, curing agents
Data Source
AI summary
Compositions containing at least one liquid epoxy resin, at least one solid epoxy resin, at least one propellant, at least one curing agent and at least one mica-containing filler produce expandable, thermally curable binder systems which may be used without the addition of hollow glass beads for the production of stiffening and reinforcing laminates and for the production of stiffening and reinforcing moldings. Said laminates according to the invention are suitable for the stiffening and reinforcing of components, in particular in the automotive industry, such as car body frames, doors, boot lids, engine bonnets and/or roof parts. In addition, the mouldings that may be produced from said binders are suitable for the stiffening and reinforcing of hollow metal structures, in particular of hollow car body parts such as body frames, body supports and posts or doors in the automotive industry.