Recycled Carpet Polymer Separation Using Terpene Solvent Extraction
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Solution Overview
Problem
Current carpet recycling methods are inefficient, resulting in low yields of reclaimed fibers and requiring large quantities of organic solvents, making it difficult to recycle carpet waste effectively and economically.
Innovation Solution
A method involving a terpene-containing solvent system is used to dissolve polymer components from carpet waste, allowing for the separation and reuse of these components, which can then be processed into new carpet materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If mechanical removal methods are used to separate carpet fibers from adhesive and backing, then fiber recovery is achieved, but the yield of recycled carpet fiber is low
Solution Approach 1:
The patent changes the physical-chemical parameters of the adhesive by treating it with aqueous alkaline solutions (changing pH and chemical composition) to modify its bonding properties. This allows the adhesive to be selectively removed or softened, enabling high-yield fiber recovery while maintaining fiber integrity. The parameter change approach transforms the adhesive from a strong binder into a removable substance, resolving the contradiction between fiber recovery and recycling efficiency.
2Ease of manufacture
If grinding and washing methods are used to separate carpet materials by density, then material separation is achieved, but the process requires large quantities of water and produces significant waste
Solution Approach 1:
The patent extracts and removes the adhesive component from the carpet assembly through chemical treatment before fiber recovery. By taking out the adhesive separately using aqueous alkaline solutions, the process eliminates the need for large-scale washing and density-based separation that would otherwise be required. This extraction approach reduces water consumption and minimizes waste generation while maintaining effective material separation.
3Loss of substance
If dissolution methods using alcohol-water or caprolactam-water agents are used to extract nylon from carpet waste, then fiber recovery is improved, but large quantities of organic solvent are required
Solution Approach 1:
The patent employs aqueous alkaline solutions (cheap, water-based) instead of expensive organic solvents like alcohol-water or caprolactam-water mixtures. The alkaline solution can be easily disposed of or regenerated, and its water-based composition eliminates the need for large quantities of organic solvents. This approach achieves effective fiber recovery while dramatically reducing solvent quantity and environmental impact.
4Ease of operation
If multiple steps of shredding, impact forces, screen separating, and hydrocyclone separation are used to recover face fiber, then fiber separation is achieved, but the process complexity increases
Solution Approach 1:
The patent applies preliminary chemical treatment with aqueous alkaline solutions to remove or soften the adhesive before mechanical separation steps. This preliminary action weakens the bonding between fibers and adhesive, making subsequent mechanical separation much more efficient. By performing the chemical preparation first, the process requires fewer and simpler mechanical separation steps, reducing overall process complexity while maintaining effective fiber recovery.
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 approach enables the efficient recovery and reuse of polymer components from carpet waste, reducing environmental impact and financial loss, while producing high-quality materials suitable for manufacturing second-generation carpets.
Implementation Method 1
A method involving a terpene-containing solvent system is used to dissolve polymer components from carpet waste
Data Source
AI summary
The present invention pertains to carpet and methods of making and recycling carpet. In one aspect, the carpet includes: a primary backing which has a face and a back surface; a plurality of fibers attached to the primary backing and extending from the face of the primary backing and exposed at the back surface of the primary backing; an adhesive composition backing; and an optional secondary backing adjacent to the adhesive backing. The method of making carpet includes extrusion coating the adhesive composition onto the back surface of a primary backing to form the adhesive composition backing. The method of recycling carpet can recover one or more polymeric carpet components.