Carpet Recycling by Selective Backing Pyrolysis and Fiber Separation
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Solution Overview
Problem
Current carpet recycling methods are inefficient and labor-intensive, with low yield and contamination issues, as they struggle to separate face fibers from backing materials without damaging the fibers or leaving contaminants behind.
Innovation Solution
A process involving heating the carpet to a temperature below the melting point of the face fibers but above the thermal decomposition temperature of the backing material, followed by mechanical liberation of the friable backing from the face fibers, allowing for effective separation and purification of the face fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shearing method is used to remove face fiber, then most of the non-face fiber portion is separated from the face fiber, but the method is labor intensive and yield is low
Solution Approach 1:
The patent replaces manual shearing operations with automated mechanical systems including conveyors, shearing blades, and sorting mechanisms that automatically process carpet through the recycling line, eliminating labor-intensive manual feeding and orientation tasks
Solution Approach 2:
The patent implements preliminary sorting and preparation steps where carpet is pre-sorted by fiber type, pre-cut into manageable sections, and pre-oriented before the main shearing process, increasing both automation efficiency and face fiber recovery yield
2Quantity of substance
If shearing method is used, then face fiber can be recovered, but the process is labor intensive requiring manual feeding
Solution Approach 1:
The patent replaces manual feeding operations with automated conveyor systems that transport carpet through the processing line, and automated cutting mechanisms that section carpet without human intervention, maintaining face fiber recovery while eliminating labor-intensive manual tasks
Solution Approach 2:
The patent implements self-aligning mechanisms and automatic feed systems where the carpet processing equipment automatically positions and feeds material through the shearing process without requiring manual orientation or feeding by operators
3Productivity
If deep cuts are made during shearing, then face fiber recovery is maximized, but cutting into the backing material contaminates the sheared fiber
Solution Approach 1:
The patent employs adjustable shearing blade systems that can be precisely positioned to cut at optimal depths for maximum face fiber recovery while preventing penetration into the backing material, with different cutting depths selectable based on carpet type and thickness
Solution Approach 2:
The patent implements dynamically adjustable cutting mechanisms where blade depth and position can be automatically adjusted based on real-time detection of carpet thickness and composition, optimizing the balance between face fiber recovery and contamination prevention for each piece of material processed
4Ease of manufacture
If whole carpet shredding is used, then processing is simplified, but the backing polypropylene fibers remain intermixed with the face fibers
Solution Approach 1:
The patent implements a segmented processing approach where the carpet recycling process is divided into distinct stages: initial shredding to break down the carpet structure, followed by separation zones where face fiber and backing material are divided using density-based separation, magnetic separation, or manual sorting stations, ensuring fiber type separation while maintaining overall process simplicity
Solution Approach 2:
The patent introduces intermediary separation steps between the initial shredding and final product formation, using intermediate processing zones with different separation mechanisms (such as air classification, water flotation, or magnetic separation) to selectively remove backing polypropylene fibers from the face fiber stream without complicating the overall process flow
5Productivity
If conventional shredding is used, then the entire carpet can be processed, but latex and inorganic filler remain attached to the face fibers
Solution Approach 1:
The patent implements extraction processes where face fibers are separated from the carpet matrix with the backing, binder, and filler materials removed or left behind in the processing line, using mechanisms such as screen sorting, density separation, or selective dissolution to extract clean face fiber while removing contaminants
Solution Approach 2:
The patent employs thermal treatment or chemical oxidation processes that selectively degrade or remove organic binders and inorganic fillers from the face fiber surface, using controlled burning, plasma treatment, or chemical baths to clean contaminants while preserving the integrity of the face fiber material
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 achieves higher recovery and quality of face fibers with reduced manpower and operating costs, while also removing contaminants and improving the hygiene of the recycled fibers.
Implementation Method 1
heating the carpet to a temperature lower than the melting point of the face fiber material, but higher than the thermal decomposition temperature of the backing material, for a time and at a temperature sufficient to decompose at least a portion of the backing material
Data Source
AI summary
Methods for the recycling of carpet are disclosed that produce clean face fiber suitable for industrial use. The methods allow the recovery of face fiber material, for example a polyester or a polyamide, from carpets that includes a face fiber material and a backing material, and include the steps of heating the carpet to a temperature lower than the melting point of the face fiber material, but higher than the initial thermal decomposition temperature of the backing material, for a time and at a temperature sufficient to thermally decompose, pyrolyze, or oxidize at least a portion of the backing material, rendering the backing material friable, that is more friable than the untreated backing; and applying mechanical force to the carpet so as to liberate the friable backing material from the face fiber material.