Olefin Interpolymer Sheath for Medium Voltage Cable
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Solution Overview
Problem
Olefin-based polymers made with constrained geometry catalysts have poor dielectric properties, making them unsuitable for use as sheaths for medium voltage cables due to high dissipation factors, which restrict their application to low voltage uses.
Innovation Solution
Developing olefin-based interpolymers using a single-site catalyst system activated with a boron-containing cocatalyst and an aluminum-containing cocatalyst, resulting in residual boron and aluminum at a molar ratio of less than one, which improves the dielectric properties of the polymers, specifically reducing the dissipation factor to less than 0.05 radians at 130°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If olefin-based polymers are made with constrained geometry catalysts activated with boron-containing cocatalyst and aluminum-containing cocatalyst, then the polymer exhibits good processability and mechanical properties, but the dielectric properties deteriorate due to high dissipation factors
Solution Approach 1:
The invention changes the chemical composition parameters of the catalyst system by controlling the molar ratio of boron to aluminum residues to be less than 1. This parameter change reduces the dissipation factor from typically high values to less than 0.05 radians at 130°C, thereby improving dielectric properties while maintaining the processability benefits of CGC-catalyzed polymers
Solution Approach 2:
The invention creates a composite catalyst system using both boron-containing cocatalyst (such as tris(pentafluorophenyl)borane) and aluminum-containing cocatalyst (such as modified methyl aluminoxane). This composite approach allows the polymer to inherit good processability from CGC catalysis while the specific composition ratio controls residual catalyst content to achieve acceptable dielectric properties for medium voltage applications
2Productivity
If conventional CGC catalyst systems are used with traditional cocatalyst ratios, then the polymer production is efficient and mechanical properties are good, but the dissipation factor remains too high for medium voltage cable applications
Solution Approach 1:
The invention modifies the cocatalyst activation parameters by establishing a specific molar ratio relationship between boron and aluminum residues (B:Al < 1). This parameter optimization maintains high polymer production efficiency through CGC catalysis while reducing the dissipation factor to acceptable levels for medium voltage cables, eliminating the harmful effect without sacrificing productivity
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 improved dielectric properties enable the use of these polymers as effective insulation layers for medium voltage cables, enhancing their suitability and performance in electrical applications.
Implementation Method 1
olefin-based polymer made with a constrained geometry catalyst (CGC) activated with a boron-containing cocatalyst and aluminium-containing cocatalyst
Implementation Method 2
The metal coordination complex typically comprises (a) an atom of titanium, hafnium or zirconium, and (b) a mono- or dicyclopentadienyl or indenyl ligand
Implementation Method 3
The improved dielectric properties enable the use of these polymers as effective insulation layers for medium voltage cables, enhancing their suitability and performance in electrical applications
Data Source
AI summary
Olefin-based polymers containing boron and aluminum at a B: Al molar ratio of less than one are useful in the manufacture of medium and high voltage wire and cable sheath coverings. Such polymers exhibit good dielectric properties, e.g., a dissipation factor less than 0.05 radians as measured by ASTM D-150-98. The typical source of the boron and aluminum in these polymers are the cocatalysts used to make the polymers, i.e., cocatalysts containing boron and/or aluminum.