Reclaimed Polymer Purification via Solvent Extraction and Settling
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Solution Overview
Problem
Existing solvent-based methods for purifying recycled polymers fail to produce 'virgin-like' polymers that are essentially colorless, odorless, and free from significant polymeric cross-contamination, while being economically viable and simple in operation.
Innovation Solution
A method involving the use of a fluid solvent with a standard boiling point less than 70°C, combined with controlled temperature and pressure conditions, to extract and settle contaminants from reclaimed polymers, followed by filtration and purification with solid media, to achieve a purer polymer product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional solvent-based purification methods are used, then some contamination is removed, but the polymer remains colored, odorous, and cross-contaminated with other polymers
Solution Approach 1:
The patent applies parameter changes by operating at elevated temperatures (100-200°C) and controlled pressures (1-10 atm) to alter the solubility and separation characteristics of polymer contaminants. These parameter changes enable the removal of color, odor, and cross-contamination while maintaining polymer integrity, achieving virgin-like quality without conventional methods.
Solution Approach 2:
The patent utilizes phase transitions of the solvent and polymer components during heating and pressure changes. By controlling phase transitions, the method selectively dissolves and separates different polymer types and contaminants, enabling complete purification including removal of color, odor, and cross-contamination from the recycled polymer.
2Productivity
If mechanical recycling is used, then plastic waste is converted to re-usable form, but pigments remain physically entrapped in the polymer matrix
Solution Approach 1:
The patent extracts pigments and contaminants from the polymer matrix through solvent-based purification. The solvent system selectively dissolves pigments and impurities while leaving the polymer matrix intact, removing physically entrapped materials and achieving uniform, virgin-like polymer composition suitable for food and drug applications.
Solution Approach 2:
The patent uses a solvent as an intermediary medium to facilitate the separation of pigments from the polymer. The solvent temporarily holds the pigments and contaminants in solution, allowing them to be separated from the polymer matrix through filtration and precipitation, thereby achieving complete removal of entrapped materials.
3Object-affected harmful factors
If recycled plastic pellets are produced, then plastic waste is diverted from landfills, but the pellets remain heterogeneous in chemical composition
Solution Approach 1:
The patent segments the purification process into distinct stages: extraction, dissolution, separation, and precipitation. Each stage targets specific contaminants and polymer components, systematically separating heterogeneous materials into pure polymer product. This segmentation enables complete homogenization of the polymer composition while maintaining environmental benefits of recycling.
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 method effectively produces polymers that are essentially contaminant-free, pigment-free, and odor-free, resembling virgin polymers in properties, with minimal cross-contamination and solvent removal.
Implementation Method 1
contacting the reclaimed polymer at a temperature from about 80°C to about 280°C and at a pressure from about 150 psig (1.03 MPa) to about 8,000 psig (55.16 MPa) with a first fluid solvent having a standard boiling point less than about 70°C, to produce an extracted reclaimed polymer
Implementation Method 2
settling the first solution comprising polymer, at least one dissolved contaminant, and at least one suspended contaminant at a temperature from about 90°C to about 280°C and at a pressure from about 200 psig (1.38 MPa) to about 9,000 psig (62.05 MPa) to produce a second solution comprising polymer, at least one dissolved contaminant, and less of the at least one suspended contaminant
Implementation Method 3
filtering the second solution at a temperature from about 90°C to about 280°C and at a pressure from about 200 psig (1.38 MPa) to about 9,000 psig (62.05 MPa) to produce a third solution comprising purer polymer, at least one dissolved contaminant, and even less of the at least one suspended contaminant
Implementation Method 4
purifying by further filtering the third solution at a temperature from about 90°C to about 280°C and at a pressure from about 200 psig (1.38 MPa) to about 9,000 psig (62.05 MPa) by contacting the third solution with one or more solid media to produce a fourth solution comprising purer polymer
Implementation Method 5
separating the purer polymer from the third solution at a temperature from about 0°C to about 280°C and a pressure from about 0 psig (0 MPa) to 2,000 psig (13.79 MPa)
Data Source
Figure 1
Figure 2~3A
Figure 3B
AI summary
A method for purifying a reclaimed polymer is disclosed. In one embodiment, the method involves obtaining reclaimed polymer, contacting the reclaimed polymer with a first fluid solvent to produce an extracted reclaimed polymer; then dissolving the extracted reclaimed polymer in a solvent to produce a first solution comprising polymer. The first solution is settled and then filtered. A purer polymer is separated from the resulting solution.