Composite Board Expanded Microspheres Uniform Cell Distribution
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Solution Overview
Problem
Existing composite panels in the construction sector face challenges with density and mechanical strength due to uneven cell distribution and open-cell foams, particularly in thicker panels, leading to instability and reduced insulation properties.
Innovation Solution
A composite panel design featuring a core layer of foamed plastic with expanded microspheres and a composite layer on both sides, where the microspheres inflate to form closed-cell foams with uniform cell sizes, achieving higher degrees of foaming and improved mechanical stability, and using a masterbatch with a carrier material for homogeneous distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If chemical foaming agents are used to achieve high degrees of foaming, then the core layer density can be reduced to 550 kg/m³, but the cell distribution becomes uneven and open-cell foams form in thicker panels
Solution Approach 1:
The patent changes the physical state and properties of the foaming agent from chemical decomposition products to expanded microspheres with controlled physical expansion. The microspheres are pre-expanded to specific sizes (30-200 μm) and then incorporated into the polymer matrix, allowing controlled foam formation without the uncontrolled cell growth and open-cell structures caused by chemical foaming agents in thick panels.
Solution Approach 2:
The patent creates a composite foam structure by combining expanded microspheres with a polymer matrix (thermoplastic or thermosetting). This composite approach allows the microspheres to provide uniform cell distribution while the polymer matrix binds them together, preventing the open-cell foam formation that occurs with chemical foaming alone in thicker panels.
2Reliability
If thermoplastics are foamed by injecting pressurized liquids or gases, then the polymer-gas mixture can be kept in solution under pressure, but the process requires very high levels of technical effort and immediate cooling
Solution Approach 1:
The microspheres are pre-expanded to the desired size range (30-200 μm) before being incorporated into the polymer matrix. This preliminary expansion action eliminates the need for complex in-process foaming control systems, as the cell structure is already formed and stabilized when the microspheres are mixed into the matrix, significantly reducing process complexity.
Solution Approach 2:
The expanded microspheres serve as their own foaming agents, providing both the gas phase and the cell structure simultaneously. This self-service approach eliminates the need for separate pressurized liquid or gas injection systems, chemical foaming agents, and complex cooling systems, dramatically simplifying the overall process.
3Manufacturing precision
If the polymer-gas mixture viscosity is increased by cooling to enable proper shaping, then the foam can be molded, but the center of thick panels cannot be cooled, causing unstable cells to burst
Solution Approach 1:
The patent segments the foaming process into two distinct stages: (1) pre-expansion of microspheres to target sizes, and (2) incorporation into the polymer matrix where they serve as stable cell structures. This segmentation eliminates the need for cooling during foaming, as the cell structure is formed and stabilized before matrix incorporation, preventing cell bursting in thick panel centers.
4Stability of the object's composition
If crosslinking the polymer matrix is used to achieve closed-cell foams, then stable cell walls can be formed, but the process becomes more complex and mechanical strengths are reduced
Solution Approach 1:
The patent uses expanded microspheres as temporary, disposable cell structures that provide the foam architecture without requiring permanent crosslinked cell walls. The microspheres serve their purpose of creating stable cell structures during processing and then remain as the final cell walls, eliminating the need for complex crosslinking reactions that would reduce mechanical strength.
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 results in a lighter, more stable panel with enhanced mechanical properties and improved insulation, achieving up to 70% foaming degrees and a core layer density of 300 kg/m³, maintaining stability across the panel thickness and offering better thermal and electrical insulation.
Implementation Method 1
Microspheres are gas-filled polymer shells that inflate like a balloon when exposed to temperature and thus form foam structures in a polymer or in the core layer
Implementation Method 2
The gas-tight sealing polymer shells of the microspheres soften during thermoplastic processing, the low-boiling liquid in the microspheres evaporates, the internal gas pressure increases and inflates the microspheres like a balloon
Implementation Method 3
The polymer-gas mixture has a very low viscosity and must be cooled so that the viscosity increases again and proper shaping is possible
Implementation Method 4
the low-boiling liquid in the microspheres evaporates, the internal gas pressure increases and inflates the microspheres like a balloon
Implementation Method 5
Various foam technologies are already being used to reduce the density of panels, thereby making them lighter
Implementation Method 6
In the case of chemically foamed thick panels, degrees of foaming of approx. 40% are usually achieved today, which leads to a core layer density of 550 kg/m³
Data Source
Figure 1
Figure 2a~2d
Figure 2e~2f
AI summary
The invention relates to a composite board (1) comprising a core layer (2) and at least one composite layer (3) connected to the core layer (2), wherein the core layer (2) is made of foamed plastic, and wherein the foamed plastic contains expanded microspheres (4), and on both sides of said core layer (2) a composite layer (3) is disposed, which in each case comprises a reinforcing layer (3b) and a cover layer (3a).