Supercritical CO2 Polymer Powder Purification Process

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Solution Overview

Problem

Existing methods, such as sieving and solvent cleaning systems, fail to effectively remove particulate contaminants from polymer powders due to similar particle sizes, affecting the aesthetic appearance and functionality of polymer-based articles.

Innovation Solution

A process involving suspending a mixture of polymer powder and particulate material in supercritical carbon dioxide, adjusting the fluid's density to separate the contaminants from the polymer powder based on specific gravity differences, forming distinct fractions for separation and purification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If sieving is used to separate particulate contaminants from polymer powder, then the separation process is simple, but the separation effectiveness is poor due to similar particle sizes

Engineering Contradiction:
Improvesimplicity of separation processVSAvoidseparation effectiveness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the physical state parameter of the separating medium from solid (sieving) to supercritical fluid. By adjusting temperature and pressure parameters, the supercritical carbon dioxide achieves a density that enables effective separation based on specific gravity differences, resolving the contradiction between process simplicity and separation effectiveness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical sieving system with a supercritical fluid extraction system. Instead of using physical screens to separate particles, the process uses supercritical carbon dioxide to selectively dissolve and separate contaminants based on density differences, achieving better separation without complex mechanical structures

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If solvent cleaning systems are used to remove contaminants, then the cleaning capability is enhanced, but residual solvent contamination remains

Engineering Contradiction:
Improvecleaning capabilityVSAvoidresidual solvent contamination
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention utilizes the phase transition properties of carbon dioxide. By controlling pressure and temperature, carbon dioxide transitions to a supercritical state for cleaning, then returns to gaseous state for easy removal. This phase transition ensures complete evaporation without residual contamination, maintaining cleaning effectiveness while eliminating harmful residuals

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention uses carbon dioxide as a disposable cleaning medium that completely evaporates after use. Unlike traditional solvents that may remain as residues, the carbon dioxide is vented away after performing the cleaning function, ensuring no harmful residuals remain on the polymer powder

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If supercritical carbon dioxide density is adjusted for separation, then polymer purity is significantly increased, but process complexity increases due to temperature and pressure control

Engineering Contradiction:
Improvepolymer purityVSAvoidtemperature and pressure control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention exploits the unique property of supercritical carbon dioxide where small changes in temperature and pressure produce large changes in density. This allows precise control of the separating medium's density to match optimal separation conditions, achieving high polymer purity while using relatively simple pressure and temperature adjustment mechanisms

Inventive Principle:
Principle #35Parameter changes

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 process significantly increases polymer purity by effectively separating particulate contaminants from the polymer powder, resulting in a high-purity polymer powder extract.

Implementation Method 1

suspending the mixture in a fluid to form a fluid suspension, wherein the fluid is supercritical carbon dioxide

Methodology Applied
Scientific EffectSupercritical fluid: Supercritical Fluid

Implementation Method 2

adjusting the density of the fluid by adjusting the temperature or pressure of the fluid so that either the first particulate material has a specific gravity relative to the fluid of more than 1 and the polymer powder has a specific gravity relative to the fluid of less than 1

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 3

adjusting the density of the fluid by adjusting the temperature or pressure of the fluid

Methodology Applied
Scientific EffectDensity gradient: Density Gradient

Data Source

PatentEP2141182B1Process
Publication Date: 2014.08.13 ORTHOPLASTICS
  • EP2141182B1 patent drawingFigure 1

AI summary

The present invention relates to a process for preparing a polymer powder extract from a mixture of a polymer powder and a first particulate material.