High Temperature Foam Surface Melting Resin Absorption
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Solution Overview
Problem
Current methods for producing high-temperature foams for sandwich materials face challenges in achieving a closed surface, leading to resin absorption and potential mechanical failures due to imperfections and cavities, which complicates lightweight construction and increases production costs.
Innovation Solution
A novel process involving the sintering of high-temperature polymer particles in a mold at a specific temperature, followed by heating the mold cavity to a higher temperature for a short duration to create a compact, impermeable surface, reducing resin absorption and cavity formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If particle foams are used for sandwich structures, then production cost is reduced and lightweight potential is maximized, but the foam surface contains voids and defects that lead to resin absorption and mechanical failure
Solution Approach 1:
The patent applies preliminary action by forming a closed-skin surface layer during the foaming process itself, before the sandwich structure assembly. The mold design with heated zones and pressure application creates a defect-free surface layer that prevents resin absorption in subsequent processing steps, thereby ensuring mechanical reliability while maintaining the cost advantages of particle foam manufacturing
2Object-affected harmful factors
If the foam surface is melted at high temperature to create a closed skin, then resin absorption is prevented, but additional process steps and energy consumption are required
Solution Approach 1:
The patent merges the surface closing function into the existing foaming process by integrating heated zones and pressure application into the mold design. This combines multiple functions (foaming, surface melting, and defect elimination) into a single integrated process step, preventing resin absorption without requiring separate additional process steps or complex equipment modifications
3Manufacturing precision
If inliners are used to modify the foam surface, then surface quality is improved, but additional materials and manufacturing steps are required
Solution Approach 1:
The patent applies self-service by enabling the foam particles themselves to form a closed-skin surface layer through controlled heating and pressure during the foaming process. The polymer material transforms and consolidates on its own to create the desired surface quality, eliminating the need for external inliners or additional coating materials and their associated manufacturing steps
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
This process results in a lightweight, mechanically stable foam core with improved surface quality, reducing resin absorption and enhancing the connection between the foam core and cover layers, while simplifying the production process and reducing energy consumption.
Implementation Method 1
the mold cavity is subsequently heated for 5 to 120 sec to a temperature T2 which is at least 10 °C above the sintering temperature and at most 20 °C above the glass transition temperature of the polymer
Implementation Method 2
heating the mold cavity to such a high temperature that the surface of the molded part becomes fluid, forming a compact skin on the foam
Implementation Method 3
Particle foams consist of numerous individual polymer foam beads that sinter together at their interfaces in a contour-defining tool under the application of energy
Data Source
Figure 1
Figure 2~3
AI summary
The present invention relates to the field of producing high- temperature foams, such as are used in the construction of aircraft, ships and rail and other vehicles, in particular further processed into sandwich materials by joining together with two outer layers. Provided for this is a novel process for producing high-temperature foams (HT foams) that are particularly suitable for producing such sandwich components for lightweight construction. This process achieves an improvement in the processability of the HT foams produced according to the invention and a weight reduction of the sandwich materials. The HT foams are furthermore rigid particle foams which, can be produced much more economically than rigid block foams. The present invention brings about in particular a reduction in the resin absorption in fibre composite processes by a process-related optimization of the surface finish.