Melt-Phase Thermoplastic Cleaning by Shear and Aqueous Separation

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Solution Overview

Problem

Existing methods for removing contaminants from recycled polymers often require solvents, caustics, or complex processes, failing to effectively address multiple types of contaminants in a simple and solvent-free manner.

Innovation Solution

A method involving shearing a combination of contaminated thermoplastic in melt form with water and a dispersing agent, followed by separation to remove contaminants, which are then separated from the thermoplastic phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If solvent extraction methods are used to remove contaminants from recycled polymers, then contaminant removal effectiveness is improved, but the process complexity and use of harmful solvents increases

Engineering Contradiction:

Improvecontaminant removal effectivenessVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes contaminants from recycled polymers using a simplified mechanical shearing process combined with water and dispersing agents, eliminating the need for complex solvent extraction systems while achieving effective contaminant removal through phase separation

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces water and dispersing agents as intermediary substances that facilitate contaminant removal through shearing and phase separation, replacing harmful organic solvents with environmentally benign alternatives that achieve similar or better removal effectiveness

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If multiple cleaning steps are used to remove different types of contaminants, then contaminant removal effectiveness is improved, but the process time and complexity increases

Engineering Contradiction:

Improvecontaminant removal effectivenessVSAvoidprocess time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent merges multiple contaminant removal functions into a single shearing step that simultaneously handles volatile organic species, solid impurities, and ash through the combined action of mechanical shearing, water extraction, and dispersing agents, eliminating the need for sequential cleaning steps

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical parameters of the cleaning process by using melt temperature conditions and mechanical shearing energy to achieve contaminant removal in a single step, replacing multiple temperature and chemical treatment stages with a unified thermal-mechanical process

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If caustic chemicals are used to remove contaminants, then contaminant removal effectiveness is improved, but environmental harm and safety risks increase

Engineering Contradiction:

Improvecontaminant removal effectivenessVSAvoidenvironmental harm

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces persistent harmful caustic chemicals with water and biodegradable dispersing agents that can be easily separated and disposed of through phase separation, eliminating long-term environmental contamination while maintaining effective contaminant removal

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the potential harm of water contact with molten polymer into a beneficial extraction mechanism, where water acts as a selective solvent that extracts contaminants from the polymer melt through shearing and phase separation, turning a potentially harmful interaction into a useful cleaning mechanism

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Achieves significant reduction in contaminants, including volatile organic species, solid impurities, and ash, while maintaining the thermoplastic's quality, without using solvents or complex processes.

Implementation Method 1

a dispersing agent

Methodology Applied

Scientific EffectSurface tension reduction: Surfactant

Implementation Method 2

subjecting to shear (i.e. shearing) a combination comprising a contaminated thermoplastic polymer in melt form

Methodology Applied

Scientific EffectShear stress: Shear Stress

Implementation Method 3

separating the thermoplastic polymer from the water, dispersing agent, contaminants that were removed from the contaminated thermoplastic during shearing

Methodology Applied

Scientific EffectDensity differential separation: Density Gradient

Data Source

PatentEP4182050B1Process for removal of contaminants from contaminated thermoplastic

Publication Date: 2025.12.24 DOW GLOBAL TECHNOLOGIES LLC

Figure 1

AI summary

A method for reducing an amount of a contaminant in a thermoplastic polymer comprising shearing a combination comprising a contaminated thermoplastic polymer in melt form, water, and a dispersing agent where the shearing causes a portion of the contaminant to be removed from the contaminated thermoplastic polymer (e.g. moved into an aqueous phase with the water or into another separate phase from the water and the polymer), and after shearing, separating the thermoplastic from the aqueous phase to recover thermoplastic polymer.