Thermoplastic Composite Recycling via Layer Peeling
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Solution Overview
Problem
Current recycling methods for thermoplastic fiber composite materials, such as carbon fiber reinforced plastics, result in downcycling due to shortening of carbon fibers and inefficient separation of matrix and fiber materials, limiting the quality and extent of recyclable material.
Innovation Solution
A method involving the peeling off of fiber composite material in layers using the reversible melting properties of the thermoplastic matrix, allowing for the preservation of fiber length and avoiding the need for matrix separation and cutting, with the potential for multiple recyclate pieces from a single component and energy savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the composite material is shredded or cut up for recycling, then the material can be processed and separated, but the fiber length is shortened leading to downcycling and inferior quality
Solution Approach 1:
The patent utilizes the reversible melting behavior of thermoplastic matrix materials. By heating the composite material to the melting point of the matrix, the matrix transitions from solid to liquid state, enabling layer separation without mechanical cutting. This phase transition approach preserves fiber length while achieving the necessary material separation for recycling.
Solution Approach 2:
The patent separates the composite material layer by layer through controlled peeling after matrix melting. Instead of shredding the entire material at once, the process segments the material into individual layers that can be processed separately, maintaining fiber integrity in each layer while enabling systematic recycling.
2Loss of substance
If pyrolysis or carbonization is used to separate matrix and fibers, then the matrix can be decomposed, but the fibers still cannot retain their original length and energy is consumed
Solution Approach 1:
The patent employs reversible melting of the thermoplastic matrix instead of irreversible pyrolysis or carbonization. The matrix is heated to its melting point, transitions to liquid state for easy separation, and can potentially be recovered or reused. This approach achieves complete matrix separation while consuming significantly less energy compared to thermal decomposition methods.
3Loss of substance
If microwave radiation or hot gas is used to decompose the matrix, then fiber separation is achieved, but the composite material must be prepared in pieces reducing fiber length
Solution Approach 1:
The patent uses controlled heating to melt the thermoplastic matrix in situ within the composite structure. This allows the matrix to transition to liquid state and be removed while the reinforcing fibers remain intact and connected, preserving their original length and continuity without requiring pre-cutting or piecewise preparation.
4Productivity
If the fiber composite material is cut into pieces for recycling, then the material can be fed to injection molding, but only short carbon fibers are obtained limiting recyclate quality
Solution Approach 1:
The patent melts the thermoplastic matrix to enable layer-by-layer peeling and separation. This allows the composite material to be processed in a controlled manner that preserves fiber length, producing high-quality recyclate with long continuous fibers suitable for advanced applications, thereby improving both recyclate quality and potential productivity.
Solution Approach 2:
The patent performs matrix melting and layer separation as preliminary actions before any cutting or shaping operations. By first transitioning the matrix to liquid state and removing it, the fibers are exposed and can then be collected in their full length, enabling subsequent processing without compromising fiber integrity or recyclate quality.
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 method enables the production of longer, high-quality recyclate fibers with reduced energy consumption, allowing for the reuse of material in its original form or for new components, effectively reversing the manufacturing process and improving recycling efficiency.
Implementation Method 1
heating with at least one heating source until the matrix material has melted at least in the detachment area
Implementation Method 2
pressing with at least one pressing element onto the fiber composite material
Data Source
Figure 1~2
AI summary
In a method and a device for recycling a thermoplastic fibre-reinforced composite material, which is in at least one deposition layer in a component (1), it is suggested that said fibre-reinforced composite material should be pulled off from the remaining component (1), in the direction of a main fibre direction, in at least one pull-off layer (10) comprising fibres and matrix material.