Fibrous Web Foam Core for Closed Mold Resin Transfer
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Solution Overview
Problem
Existing core materials for fiber-reinforced plastics in closed mold systems lose compression resistance and drapability when subjected to elevated pressures, compromising their ability to maintain volume and facilitate resin flow.
Innovation Solution
A core material comprising a fibrous web with a foam structure and a polymer hardener, which provides enhanced compression resistance and permeability, allowing it to maintain shape and facilitate resin flow under pressure while retaining drapability properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If core material is used under elevated pressures in closed mold systems, then resin flow through the core material is improved, but the core material is compressed and loses volume, reducing its compression resistance and drapability
Solution Approach 1:
The core material uses a composite structure combining a foam core with a fibrous web overlay. The foam provides compressibility and volume reduction under pressure, while the fibrous web maintains structural integrity and compression resistance. This composite approach allows the material to flow resin effectively while maintaining its shape and mechanical properties under elevated pressures.
Solution Approach 2:
The invention changes the physical parameters of the core material by using a foam structure with specific cell sizes and densities. The foam cells are designed to collapse controllably under pressure, allowing volume reduction for resin flow while the fibrous reinforcement maintains overall structural stability. This parameter optimization enables both good resin permeability and compression resistance simultaneously.
2Productivity
If core material is compressed under elevated pressure, then resin can flow through the material, but the core material cannot recuperate its lost volume after pressure is released
Solution Approach 1:
The core material exhibits different local properties: the foam interior is designed to be compressible for volume reduction during resin injection, while the fibrous web surface maintains structural stability and shape retention. This local differentiation allows the material to be compressed locally for resin flow while maintaining overall volume stability and shape after pressure release.
3Productivity
If core material is made more compressible to allow resin flow, then permeability improves, but drapability and shape conformity are compromised
Solution Approach 1:
The core material is segmented into two functional layers: a foam layer that provides compressibility and resin permeability, and a fibrous web layer that provides drapability and shape conformity. This segmentation allows each layer to perform its specific function optimally - the foam enables resin flow while the fibrous web ensures the material can be draped and conforms to mold shapes.
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 core material achieves over 60% compression resistance at 6 bar and improved resin permeability, enabling efficient resin penetration and maintaining shape conformity, outperforming previous materials in terms of mechanical properties and flow characteristics.
Implementation Method 1
the core material will be compressed and thus be reduced in volume. Such pressure is only released after the mold is filled. As a result, the core material can not recuperate from the compression to regain its lost volume.
Implementation Method 2
allowing fast flow of the resin through the core materials in all directions without taking up too much resin
Data Source
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AI summary
The invention is in the field of core material for use in a closed mold system in the production of fiber reinforced plastic materials. The invention is particularly directed to core materials for use in press-forming or resin transfer and autoclave molding. In accordance with the invention there is provided a core material based on at least one fibrous web containing a foam structure within and/or on the web, wherein said foam structure is formed by a plurality of members that are separated by channels, wherein the core material further comprises a hardener based on a polymer dispersion.