Polycarbonate Resin Recycling with Agglomeration for Color and Strength

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Solution Overview

Problem

Existing methods for recycling polycarbonate resins face challenges in achieving good color tone and mechanical properties due to the difficulty in separating additives and degraded components, limiting their practical use in applications requiring transparency and mechanical strength.

Innovation Solution

A method involving dissolving polycarbonate resin waste in a good solvent, contacting the solution with an agglomerating agent to remove undissolved substances, followed by precipitation with a poor solvent, and optionally using a filter aid to produce a recycled polycarbonate resin with improved color tone and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If material recycling is used to recycle polycarbonate resin, then the recycling process is simpler compared to chemical recycling, but the color tone and mechanical properties of the recycled resin are insufficient for practical use

Engineering Contradiction:

Improverecycling process simplicityVSAvoidcolor tone and mechanical properties

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The recycling process is divided into multiple sequential steps: dissolution in good solvent, filtration to remove undissolved substances, precipitation with poor solvent, and collection. This segmentation allows each step to target specific impurities while preserving the polycarbonate resin, achieving both process simplicity and high product quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Solvents are used as intermediary substances to facilitate separation. The good solvent dissolves the polycarbonate resin while leaving impurities undissolved, and the poor solvent induces precipitation of pure resin. This intermediary approach enables effective separation without complex chemical reactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If conventional material recycling without agglomerating agent is used, then the process is simpler, but additives and degraded components remain difficult to separate

Engineering Contradiction:

Improveprocess complexityVSAvoidseparation efficiency of additives and degraded components

Core Design Contradiction:

Device complexityVSLoss of substance

Solution Approach 1:

An agglomerating agent is introduced as an intermediary substance that bridges the gap between simple filtration and complex separation. The agent causes fine particles of additives and degraded components to clump together into larger agglomerates that can be easily removed by filtration, improving separation efficiency without significantly increasing process complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The method replaces complex mechanical separation systems with a chemical approach using the agglomerating agent. Instead of using sophisticated filtration systems or multiple separation stages, the chemical aggregation simplifies the physical separation process while achieving superior removal of impurities.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 removes impurities, resulting in a recycled polycarbonate resin with acceptable color tone and mechanical properties suitable for practical use, overcoming the limitations of conventional recycling methods.

Implementation Method 1

preparing a polycarbonate resin solution by dissolving the polycarbonate resin waste raw material in a good solvent in which the polycarbonate resin waste raw material is soluble

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

bringing the polycarbonate resin solution into contact with an agglomerating agent, and subsequently removing undissolved substances

Methodology Applied

Scientific EffectAgglomeration: Coagulation

Implementation Method 3

precipitating the recycled polycarbonate resin by mixing the solution (L) with a poor solvent

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentEP4644472A1Method for producing reclaimed polycarbonate resin

Publication Date: 2025.11.05 MITSUBISHI CHEM CORP

AI summary

Provided is a production method capable of producing a recycled polycarbonate resin having a good color tone and good mechanical properties. The method for producing a recycled polycarbonate resin according to the present invention includes step (S1) of preparing a polycarbonate resin solution by dissolving the polycarbonate resin waste raw material in a good solvent, step (S2) of bringing the polycarbonate resin solution into contact with an agglomerating agent, and subsequently removing undissolved substances to prepare a solution (L) free of undissolved substances, step (S3) of precipitating the recycled polycarbonate resin by mixing the solution (L) with a poor solvent, and step (S4) of recovering the precipitated recycled polycarbonate resin.