Crosslinked Polyethylene Pipe Composition for High Pressure Resistance
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Solution Overview
Problem
Existing crosslinked polyethylene pipes, particularly PE-Xa, face challenges in achieving high melt index and density while maintaining a sufficient degree of crosslinking, which affects pressure resistance and physical properties.
Innovation Solution
A crosslinked polyethylene pipe is developed with specific molecular weight and density ranges, using a hybrid metallocene catalyst system to enhance melt index and density, ensuring a high degree of crosslinking and improved pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If polyethylene with high melt index is used to increase density and improve pressure resistance, then pressure resistance is improved, but the degree of crosslinking is lowered
Solution Approach 1:
The patent applies parameter changes by precisely controlling the melt index within the range of 1-20 g/10min and density within 0.940-0.960 g/cm³. This optimization balances the chain mobility needed for high density with sufficient molecular weight to maintain crosslinking degree, resolving the contradiction between pressure resistance and crosslinking quality
Solution Approach 2:
The patent uses a composite approach by combining polyethylene with specific molecular weight distribution and controlled low molecular weight content with optimized crosslinking agents. This creates a composite material system where the polyethylene base provides density and pressure resistance while the controlled composition ensures adequate crosslinking degree
2Stress or pressure
If polyethylene with high density is used to improve pressure resistance, then pressure resistance is improved, but chain mobility is reduced
Solution Approach 1:
The patent optimizes the melt index parameter within 1-20 g/10min to balance density and chain mobility. This controlled parameter range ensures sufficient chain mobility for processing and flexibility while achieving the required density for pressure resistance, resolving the contradiction between these two properties
3Quantity of substance
If a large amount of low molecular weight is produced to increase chain mobility and density, then density is improved, but the degree of crosslinking is lowered
Solution Approach 1:
The patent controls the low molecular weight content within 20-40% of the total molecular weight distribution. This parameter optimization ensures sufficient chain mobility and density while maintaining enough high molecular weight content to achieve adequate crosslinking degree, resolving the contradiction between quantity and quality
Solution Approach 2:
The patent applies local quality by creating a bimodal molecular weight distribution where different portions of the polymer chains serve different functions: lower molecular weight portions provide chain mobility and density, while higher molecular weight portions ensure crosslinking degree. This local differentiation of molecular weight qualities resolves the contradiction
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 polyethylene exhibits excellent strength and pressure resistance, suitable for producing flexible PE-Xa pipes with enhanced crosslinking properties.
Implementation Method 1
a first metallocene compound and a second metallocene compound
Implementation Method 2
crosslinked polyethylene which is modified into polyethylene having a three-dimensional network structure by crosslinking
Data Source
AI summary
The present disclosure relates to a polyethylene having high pressure resistance and a crosslinked polyethylene pipe including the same. The polyethylene according to the present disclosure has high melt index and density and exhibits a sufficient degree of crosslinking, thereby exhibiting excellent strength and pressure resistance characteristics.