Sequential Polymer Degradation in Extruder Sections
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Solution Overview
Problem
Existing methods for degrading polymers in extruders using free-radical generators like peroxides face safety concerns, inefficiencies, and high costs, while using oxygen alone struggles with reproducibility and achieving low viscosity polymers.
Innovation Solution
A sequential degradation process in an extruder with two sections, where the first section uses a free-radical generator to reduce polymer molecular weight, followed by oxygen gas in the second section to further degrade the polymer, with a sealant preventing oxygen escape and ensuring controlled degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If peroxides are used as free-radical generators to degrade polymers, then degradation efficiency is improved, but safety risks and cost increase
Solution Approach 1:
The degradation process is divided into two sequential sections: first using peroxides for initial degradation, then using oxygen for further degradation. This segmentation allows each agent to work optimally without the full risks and costs of using only one agent throughout the entire process.
Solution Approach 2:
The patent uses a reduced amount of peroxide compared to traditional single-stage processes, applying it only in the first section. The remaining degradation is achieved through oxygen in the second section, thus using partial action of the hazardous agent while still achieving complete degradation.
2Productivity
If peroxides are used as free-radical generators, then degradation efficiency is improved, but process cost increases
Solution Approach 1:
The degradation process is divided into two sequential sections: first using peroxides for initial degradation, then using oxygen for further degradation. This segmentation allows each agent to work optimally without the full risks and costs of using only one agent throughout the entire process.
Solution Approach 2:
The patent uses a reduced amount of peroxide compared to traditional single-stage processes, applying it only in the first section. The remaining degradation is achieved through oxygen in the second section, thus using partial action of the hazardous agent while still achieving complete degradation.
3Reliability
If oxygen is used alone to degrade polymers, then safety is improved, but degradation effectiveness decreases
Solution Approach 1:
The degradation process is divided into two sequential sections: first using peroxides for initial degradation, then using oxygen for further degradation. This segmentation allows each agent to work optimally without the full risks and costs of using only one agent throughout the entire process.
Solution Approach 2:
The patent combines two degradation mechanisms (peroxide-based free-radical degradation and oxygen-based oxidation) into a single sequential process, merging the advantages of both methods while mitigating their individual disadvantages.
4Productivity
If oxygen is supplied into the extruder, then degradation continues, but uncontrolled foaming occurs
Solution Approach 1:
The extruder is divided into two sections separated by a sealant. Oxygen is supplied only in the second section after the sealant, preventing it from reaching the first section where volatile components are present, thus avoiding foaming while maintaining degradation effectiveness.
Solution Approach 2:
A sealant is introduced as an intermediary element between the first and second sections. This sealant blocks the passage of oxygen into the first section, preventing the harmful interaction between oxygen and volatile components that would cause foaming.
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 achieves a significant reduction in polymer molecular weight and viscosity efficiently and safely, using minimal radical formers and lower temperatures, while avoiding undesirable foaming and reducing energy consumption.
Implementation Method 1
Degrading the (co)polymer under shearing stress in the first extrusion section in the presence of at least one free-radical generator
Implementation Method 2
degraded in a first extrusion section by the action of at least one free-radical generator, while in a second extruder section there is further degradation of the (co)polymer is achieved by means of an oxygen gas
Implementation Method 3
further degradation of the (co)polymer is achieved by means of an oxygen gas
Implementation Method 4
the sealant is capable of preventing the oxygen gas from escaping from the charging port
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method for degrading (co)polymers in an extruder and an extruder suitable for performing said method.