Filled Polymer Mixing Under Vacuum to Prevent Hydrolytic Degradation

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Solution Overview

Problem

The production of thermoplastic polymer materials like PET filled with fillers, such as calcium carbonate, is hindered by hydrolytic degradation due to residual moisture, making recycling and processing economically inefficient and quality control challenging, especially when pre-drying fillers is complex and costly.

Innovation Solution

A process involving the mixing of not yet molten, optionally softened PET with fillers under vacuum conditions and constant agitation at elevated temperatures, using fillers with residual moisture above 500 ppm, eliminates the need for pre-drying and reduces hydrolytic degradation, allowing for efficient and cost-effective production of high-quality filled polymers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fillers are pre-dried before addition to polymer, then hydrolytic degradation is prevented, but process complexity and cost increase

Engineering Contradiction:

Improveprevention of hydrolytic degradationVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The polymer material is pre-softened or pre-heated before filler addition, creating optimal conditions for immediate mixing and subsequent drying, thereby eliminating the need for separate pre-drying of fillers while preventing hydrolytic degradation through timely moisture removal

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The filler addition and drying operations are merged into a single integrated process step, where fillers are added to softened polymer and moisture is removed simultaneously through vacuum or gas flow, eliminating the need for separate pre-drying operation

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If fillers with high residual moisture are used, then production cost decreases, but hydrolytic degradation occurs

Engineering Contradiction:

Improveproduction costVSAvoidpolymer chain integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The temperature and vacuum parameters are optimized during the mixing process to enable effective moisture removal from fillers with high residual moisture content, allowing use of cost-effective non-pre-dried fillers while maintaining polymer integrity through controlled drying conditions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

A protective atmosphere (nitrogen or carbon dioxide) is introduced as an intermediary medium to displace oxygen and prevent oxidative degradation while facilitating moisture removal from fillers, enabling cost reduction without compromising product quality

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If mixing is performed at elevated temperature, then mixing efficiency improves, but thermal degradation may occur

Engineering Contradiction:

Improvemixing efficiencyVSAvoidthermal degradation

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

An inert atmosphere (nitrogen or carbon dioxide) is maintained during high-temperature mixing to exclude oxygen and prevent oxidative degradation, allowing elevated temperature processing to improve mixing efficiency without causing thermal or oxidative damage to the polymer

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The mixing process is performed continuously under optimized temperature and vacuum conditions, maintaining consistent shear forces and thermal energy input to ensure complete filler dispersion and moisture removal while preventing localized thermal degradation through continuous motion

Inventive Principle:

Principle #20Continuity of useful 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

This method prevents hydrolytic and oxidative degradation, enables the use of non-pre-dried fillers, simplifies the production process, and results in qualitatively better end products by maintaining polymer chain length and viscosity, while reducing processing time and costs.

Implementation Method 1

mixing of not yet molten, optionally softened polymer material with the filler under vacuum conditions

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

constant agitation and thorough mixing and elevated temperature

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

constant agitation and thorough mixing

Methodology Applied

Scientific EffectMixing: Stirring

Data Source

PatentUS8901224B2Process for producing a filled polymer material

Publication Date: 2014.12.02 EREMA ENGINEERING RECYCLING MASCHINEN & ANLAGEN GMBH

AI summary

The invention relates to a method for producing a thermoplastic polymer material that is filled with at least one filler, preferably calcium carbonate CaCO3, sensitive to hydrolytic degradation and optionally hygroscopic, and produced by way of polycondensation, particularly PET, wherein under vacuum conditions, constant stirring or mixing and an increased temperature, a mixture of not yet melted, optionally softened, polymer material comprising the filler is produced, wherein for this purpose a filler, which at the time of addition has not been pre-dried and has a residual moisture (H2O) of more than 500 ppm, particularly more than 1000 ppm, is used.