Recycling MMA Monomers via Thermal Cleavage and Purification

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Solution Overview

Problem

Current processes for producing poly(alkyl(meth)acrylates from recycled materials result in low purity and high emissions, limiting their application due to contamination from additives and impurities, and inefficient separation of by-products.

Innovation Solution

A process involving thermal cleavage of polymer compositions to produce a gas stream containing alkyl(meth)acrylate and ester, followed by condensation, mixing with a further stream, partial polymerization, and degassing in a extruder to achieve high purity poly(alkyl(meth)acrylates with efficient separation of impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If thermal depolymerization is used to recycle PMMA, then monomer yield is improved, but purity of recycled alkyl (meth)acrylate deteriorates due to contamination from additives and impurities

Engineering Contradiction:
Improvemonomer yieldVSAvoidpurity of recycled alkyl (meth)acrylate
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent segments the recycled monomer production process into distinct stages: thermal depolymerization to obtain crude monomer mixture, followed by separate purification steps including distillation and washing. This segmentation allows the quantity of monomer to be maximized in the depolymerization stage while purity is addressed in subsequent independent purification stages, resolving the contradiction between yield and purity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts harmful impurities and additives from the recycled monomer through multiple purification steps. Distillation extracts monomer from the depolymerization mixture, while subsequent washing steps extract remaining contaminants. This extraction process separates the desired monomer (improving purity) while recovering maximum monomer content (maintaining yield).

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If conventional depolymerization processes are used, then processing speed is improved, but harmful emissions increase due to inefficient separation of by-products

Engineering Contradiction:
Improveprocessing speedVSAvoidharmful emissions
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful by-products and impurities generated during depolymerization into separable components through systematic purification. The inefficient separation issue is transformed into an advantage by implementing multiple staged separation processes (distillation, washing) that efficiently remove contaminants while recovering valuable monomer, thus converting potential emissions into purified product and separable waste streams.

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

Solution Approach 2:

The patent applies preliminary purification actions immediately after depolymerization, including distillation and washing steps before the recycled monomer is reused. This preliminary treatment prevents harmful substances from being carried forward in the recycling process, addressing emissions proactively while maintaining continuous processing speed.

Inventive Principle:
Principle #10Preliminary action

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 process achieves poly(alkyl(meth)acrylates with purities over 99%, suitable for both clear and colored applications, with reduced CO2 emissions and minimal odor, enabling their reuse in circular economies.

Implementation Method 1

thermal cleavage of a polymer composition containing at least one poly(alkyl(meth)acrylate) to obtain a first gas stream containing at least one alkyl(meth)acrylate and at least one further alkyl ester

Methodology Applied
Scientific EffectThermal depolymerization: Pyrolysis

Implementation Method 2

condensing the first gas stream obtained in step a) to obtain a liquid first stream containing the at least one alkyl(meth)acrylate and the at least one further alkyl ester

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4435019A1Recycle mma and use thereof in a continuous polymerization process
Publication Date: 2024.09.25 ROHM GMBH
  • EP4435019A1 patent drawingFigure 1~2
  • EP4435019A1 patent drawingFigure 3
  • EP4435019A1 patent drawing

AI summary

The present invention relates to a novel process for the production of a poly(alkyl(meth)acrylate). In this process, a polymer composition containing at least one poly(alkyl(meth)acrylate) is first thermally cleaved to obtain at least one alkyl(meth)acrylate and at least one further alkyl ester. This mixture is then condensed and mixed with a stream from a poly(alkyl(meth)acrylate) production process. The poly(alkyl(meth)acrylate) is then obtained by polymerization.