Glass-Fiber Reinforced Plastic Recycling by Depolymerization
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Solution Overview
Problem
Existing recycling methods for glass fiber reinforced plastics (GRP) fail to produce high-quality recyclates due to issues like fiber shortening, additive degradation, and contamination, making large-scale recycling economically unviable and environmentally harmful.
Innovation Solution
A process that depolymerizes up to 80% of the polymer matrix in GRP without water, separates glass fibers from polymer residues, and uses the remaining organic fraction's combustion heat to melt and purify the glass, effectively removing contaminants and additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical recycling processes (shredding, melting, compounding) are used to recycle GRP, then the plastic waste can be processed into recyclates, but the glass fibers are mechanically shortened and the quality of the recyclate deteriorates
Solution Approach 1:
The invention changes the fundamental parameter of the recycling approach from mechanical processing to chemical processing. By using depolymerization conditions (temperature, catalyst, time), the polymer matrix is selectively broken down into monomers while leaving the glass fibers intact, thus avoiding mechanical fiber shortening and maintaining manufacturing precision
Solution Approach 2:
The invention utilizes phase transitions in the chemical sense - the polymer matrix transitions from a high molecular weight solid to low molecular weight monomers through depolymerization. This chemical phase change allows separation of the polymer from the glass fibers without mechanical force, preserving fiber length and quality
2Manufacturing precision
If melt filters are used to improve recyclate quality in mechanical recycling, then contamination is reduced, but glass fibers prevent effective use of melt filters
Solution Approach 1:
The invention changes the processing parameter from mechanical melting and filtration to chemical depolymerization. This fundamental parameter change makes the process adaptable to GRP materials, as the polymer matrix is chemically converted to soluble monomers that can be separated from glass fibers through filtration without the issues associated with melt filtration of fiber-reinforced plastics
3Ease of manufacture
If physical processes alone are used for recycling GRP, then the process is simple and energy-efficient, but the quality level of the recyclate is insufficient and downgrading occurs
Solution Approach 1:
The invention introduces chemical parameters (catalyst, temperature, time) to the recycling process, transforming it from a purely physical process to a chemical process. This parameter change enables high-quality recyclate production by selectively depolymerizing the polymer matrix while preserving the glass fibers, achieving both process efficiency and high manufacturing precision
Solution Approach 2:
The invention replaces the mechanical recycling system (shredding, melting, filtration) with a chemical system based on depolymerization. This substitution eliminates the need for complex mechanical processing steps while achieving superior separations and recyclate quality, maintaining ease of manufacture through a single integrated chemical process
4Strength
If glass fiber content in GRP is increased to improve strength and stiffness, then mechanical properties are enhanced, but recycling becomes more difficult and downgrading is encouraged
Solution Approach 1:
The invention changes the recycling approach from mechanical to chemical processing, with the parameter change being the use of depolymerization conditions. This enables effective recycling of high glass fiber content materials by selectively breaking down the polymer matrix chemically, thereby maintaining the reinforcing effect of glass fibers in the recyclate without increasing process complexity
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
Produces high-quality glass fibers and polymer monomers suitable for virgin-grade recycling, maintaining product quality and reducing environmental impact.
Implementation Method 1
the cleavage product is ε-caprolactam and the polymer matrix is based on polyamide 6, wherein at least 50 wt.-% of the polymer matrix is depolymerized, Depolymerization means the heating of the glass fiber reinforced plastic, the addition of additives and the pyrolytic cleavage under exclusion of air
Implementation Method 2
using the organic portion remaining in the residue at the end of process step a) as an energy supplier using its heat of combustion to heat and melt the glass-based component
Implementation Method 3
using its heat of combustion to heat and melt the glass-based component and at the same time to remove the organic components by converting it into gaseous combustion products and c) separating the glass melt for further processing
Data Source
AI summary
The invention relates to a method for recycling glass fibre reinforced plastic, in particular plastic based on polyamide, polybutylene terephthalate or polyethylene terephthalate, in order to obtain monomers from the polymers as well as for retrieving the glass used for the glass fibre.