Recycled Polyethylene Pipe Melt Flow Rate Control
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Solution Overview
Problem
Existing methods for producing pipes from recycled polyethylene face challenges in achieving a broad range of melt viscosity and controlled melt flow rate (MFR), which limits their suitability for pipe manufacturing due to high MFR values in recycled materials from consumer packaging and film applications.
Innovation Solution
A process involving the extrusion of recycled polyethylene with a free radical generator, such as organic peroxides, to modify the polyethylene, reducing MFR to values comparable to virgin materials, while maintaining lower torque and energy consumption, using the equation MFRf = MFR0 × e^(-µX) to achieve desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If recycled polyethylene with high MFR is used for pipe production, then the availability of recyclate volume increases, but the melt flow rate becomes too high for suitable pipe manufacturing
Solution Approach 1:
The patent applies parameter changes by systematically varying the peroxide concentration (from 200 ppm to 4000 ppm) to control the MFR of modified recycled polyethylene. The exponential decay relationship MFRf = MFR0 × e^(-µX) demonstrates how changing the peroxide concentration parameter directly controls the final MFR parameter, enabling recycled polyethylene with initially high MFR to be transformed into suitable pipe production material.
2Manufacturing precision
If peroxide is added to modify polyethylene MFR, then the melt flow rate is reduced to suitable levels, but the processing characteristics and energy consumption must be optimized
Solution Approach 1:
The patent implements feedback control through the exponential decay equation MFRf = MFR0 × e^(-µX), where the final MFR is directly related to the peroxide concentration. This allows for precise control and optimization of the modification process, enabling operators to select the minimum necessary peroxide dosage to achieve target MFR values, thereby optimizing energy consumption while maintaining processing characteristics.
3Ease of manufacture
If recycled polyethylene is used instead of virgin material, then ecological benefits and cost reduction are achieved, but the molecular weight distribution and melt viscosity are insufficient for pipe production
Solution Approach 1:
The patent uses peroxide as an intermediary substance that mediates between recycled polyethylene with unsuitable molecular weight distribution and the required pipe production specifications. The peroxide initiates free radical reactions that modify the polymer chains, effectively acting as a bridge that transforms the recyclate into a material with appropriate rheological properties while maintaining the ecological and economic advantages of using recycled content.
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 successfully produces pipes with a broad range of MFR, comparable to those made from virgin materials, with lower energy consumption and improved processing characteristics, enabling the use of recycled polyethylene in pipe production.
Implementation Method 1
extruding the recycled polyethylene in the presence of a free radical generator so as to form a modified polyethylene
Implementation Method 2
a free radical generator, such as organic peroxides
Data Source
AI summary
The invention is related to a pipe produced by a reactive modification of a recycled polyethylene in the presence of a free radical generator. Further, the present invention is also directed to a process in a controlled manner for producing pipes from modified polyethylene recyclates having broader MFR range.