Capillary Rheometer Method for PCR Resin Extrudability Classification

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Solution Overview

Problem

Polyethylene post-consumer recycled (PCR) resins face challenges in classification and processing due to deteriorated physical properties and foreign matter content, making it difficult to distinguish between recyclable and non-recyclable grades, and existing analysis methods are costly and inefficient.

Innovation Solution

A method using a capillary rheometer to determine the extrudability of PCR resins by measuring initial pressure, piston and capillary diameter ratios, and sieve mesh sizes, allowing for the classification and blending of PCR resins with new materials to enhance processability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If PCR resin is processed through extrusion, then the resin can be reused for manufacturing, but foreign matter accumulates and blocks the filter, making continuous processing difficult

Engineering Contradiction:

Improvecontinuous processing capabilityVSAvoidfilter blockage resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary classification of PCR resin into grade A (low foreign matter) and grade C (high foreign matter) before extrusion processing. By separating resins based on foreign matter content in advance, the system prevents filter blockage before it occurs, enabling continuous processing of grade A resin without interruptions for filter maintenance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments PCR resin into different grades (grade A and grade C) based on foreign matter content. This segmentation allows the system to process only the suitable grade A resin through extrusion, while excluding grade C resin that would cause filter blockage, thereby maintaining continuous productivity.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If advanced analysis methods (ICP, TGA) are used to classify PCR resin grades, then classification accuracy improves, but analysis cost increases significantly

Engineering Contradiction:

Improveresin grade classification accuracyVSAvoidanalysis cost

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent replaces expensive, sophisticated analysis equipment (ICP, TGA) with a simple, low-cost viscosity measurement method using a rotational viscometer. This disposable-like approach uses inexpensive measurement tools that provide sufficient classification accuracy for practical purposes without the high costs of advanced analytical instruments.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes complex chemical and thermal analysis systems (ICP for elemental analysis, TGA for pyrolysis analysis) with a simple mechanical measurement system (rotational viscometer). This mechanical substitution achieves adequate classification accuracy at a fraction of the cost of sophisticated analytical methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If visual inspection is used to classify PCR resin, then cost is low, but classification accuracy is insufficient to distinguish grade A from grade C

Engineering Contradiction:

Improveclassification costVSAvoidgrade differentiation accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent replaces subjective visual inspection with an objective mechanical measurement system (rotational viscometer). This substitution provides quantifiable viscosity data that accurately reflects foreign matter content, enabling reliable differentiation between grade A and grade C resin without the cost of advanced analytical equipment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the classification parameter from visual appearance (subjective and insufficient) to viscosity measurement (objective and quantitative). By measuring viscosity at specific temperatures and shear rates, the system transforms an inadequate classification approach into a precise one that can reliably distinguish between resin grades.

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

Enables easy classification and processing of PCR resins, ensuring continuous extrudability and maintaining excellent physical properties, reducing the need for costly analysis and preventing foreign matter-induced blockages.

Implementation Method 1

passing the PCR resin through a capillary rheometer to determine whether: (1) a total capacity of the PCR resin at which an initial pressure (P0) becomes doubled (Pt)

Methodology Applied

Scientific EffectCapillary rheometry: Rheometer

Data Source

PatentUS20240410805A1Method for Measuring Easily Extrusion-Moldable PCR Resin and PCR Resin Composition

Publication Date: 2024.12.12 SK INNOVATION CO LTD

AI summary

Provided is a method for determining whether a post-consumer recycled (PCR) resin is an easily extrudable PCR resin by adding the PCR resin to a capillary rheometer and quantifying a volume value measured when a pressure is increased to a certain level, which is a method for providing determination information of the easily extrudable PCR resin.