Method for manufacturing bulked continuous filament
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost of pure virgin PET polymer and the environmental benefits of using recycled PET polymer make it desirable to produce bulked continuous carpet filament from 100% recycled PET polymer, but existing methods are inefficient in removing contaminants and require multiple melting and cooling cycles, resulting in suboptimal polymer quality.
Innovation Solution
A process involving sorting, washing, and extrusion of PET flakes from post-consumer bottles using a Multiple Rotating Screw (MRS) extruder to purify and melt the PET, removing contaminants and interstitial water, which maintains the polymer quality suitable for producing high-quality bulked continuous carpet filament without the need for multiple cooling cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple melting and cooling cycles are used to purify recycled PET polymer, then polymer quality is improved, but processing time and energy consumption increase significantly
Solution Approach 1:
The patent applies preliminary action by performing thorough washing and contaminant removal on PET flakes before the melting process. This pre-treatment eliminates the need for multiple melting and cooling cycles, as contaminants are removed in advance during the washing stage, thereby reducing processing time while maintaining polymer quality
Solution Approach 2:
The patent extracts and removes contaminants and interstitial water from recycled PET polymer during the extrusion process using a specialized extruder with filtration systems. This extraction of harmful impurities in a single pass eliminates the need for repeated melting and cooling cycles, resolving the contradiction between polymer quality improvement and processing time reduction
2Manufacturing precision
If multiple melting and cooling cycles are used to remove contaminants from recycled PET, then polymer purity is improved, but energy consumption increases
Solution Approach 1:
The patent performs preliminary washing and contaminant removal before melting, which reduces the need for multiple energy-intensive melting and cooling cycles. The pre-treatment stage removes most contaminants in advance, thereby reducing overall energy consumption while maintaining polymer purity
Solution Approach 2:
The patent extracts contaminants and interstitial water during a single extrusion process using filtration systems integrated into the extruder. This single-pass extraction eliminates the need for multiple repeated melting cycles, significantly reducing energy consumption while achieving the required polymer purity
3Ease of manufacture
If recycled PET polymer is used instead of virgin PET polymer, then cost is reduced and environmental benefits are achieved, but polymer quality and strength decrease
Solution Approach 1:
The patent extracts and removes contaminants and interstitial water from recycled PET polymer through a specialized extrusion process with integrated filtration. This thorough purification of recycled material restores its strength and quality properties, making it comparable to virgin PET while maintaining the cost and environmental advantages of using recycled content
Solution Approach 2:
The patent changes the physical and chemical parameters of recycled PET polymer during extrusion, including temperature control, shear rate, and filtration parameters, to optimize the purification process. These parameter adjustments ensure that recycled polymer achieves the necessary strength and quality standards for carpet filament production
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 process effectively removes contaminants and water, achieving an intrinsic viscosity of at least 0.79 dL/g, enabling the production of high-quality recycled PET polymer suitable for 100% recycled content carpet filament with improved strength and processing speed.
Implementation Method 1
passing the flakes through an extruder that melts the flakes and purifies the resulting PET polymer
Implementation Method 2
A MRS extruder receives the group of flakes and extrudes the flakes while maintaining a pressure within an MRS portion of the MRS extruder below about 1.5 millibars
Implementation Method 3
passing the resulting molten polymer through a filtration system
Implementation Method 4
maintaining the pressure within an MRS portion of the MRS extruder below about 1.5 millibars
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of recycling polymers and other plastics comprises: (A) grinding recycled PET bottles (or other suitable recycled polymer) into a group of flakes; (B) washing the flakes; (C) identifying and removing impurities, including impure flakes, from the group of flakes; (D) passing the group of flakes through an MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 5 millibars; (E) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (F) preparing the polymer melt for recycling into a new product. In various embodiments, the above process may be utilized in the recycling of, for example, polytrimethylene terephthalate (PTT), polypropylene, polyvinyl chloride (PVC), high-density polyethylene (HDPE), polystyrene (PS), expanded polystyrene (EPS), or any other suitable polymer or plastic