Interpolymer Cable Insulation Cross-Linking Efficiency
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Solution Overview
Problem
Current cross-linkable polyethylene-based insulators for power cables have limitations in efficiency and extent of cross-linking due to insufficient labile unsaturation sites, necessitating improvements in interpolymer formulations for enhanced performance.
Innovation Solution
A cable or wire insulation material comprising an interpolymer with ethylene monomer residues and a non-conjugated diene comonomer, where the diene comonomer constitutes 0.001 to 1 mole percent, polymerized in the presence of a free-radical initiator at temperatures ranging from 120 to 360 °C, to enhance cross-linking and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyethylene or EPR is used as insulation material, then the material is easy to manufacture and process, but the cross-linking efficiency and extent are insufficient due to inadequate labile unsaturation sites
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyethylene by incorporating small amounts (0.001-1 mole percent) of non-conjugated diene comonomers with specific structures (divinyl, vinylidene, or allyl groups). This parameter change introduces labile unsaturation sites that enhance cross-linking efficiency while maintaining the base polymer's ease of manufacture.
Solution Approach 2:
The invention creates a composite polymer structure by combining conventional polyethylene chains with incorporated non-conjugated diene units. This composite approach allows the material to retain the processability of polyethylene while gaining the cross-linking capability from the diene residues, resolving the contradiction between manufacturing ease and cross-linking performance.
2Reliability
If the amount of non-conjugated diene comonomer is increased to improve cross-linking, then cross-linking efficiency improves, but the polymerization process complexity and cost increase
Solution Approach 1:
The patent applies partial action by incorporating only small amounts (0.001-1 mole percent) of non-conjugated diene comonomer, which is sufficient to provide the necessary labile unsaturation sites for effective cross-linking without requiring large additions that would complicate the polymerization process or increase costs significantly.
Solution Approach 2:
By optimizing the diene comonomer content to a specific range (0.001-1 mole percent), the patent finds the optimal parameter balance where cross-linking efficiency is substantially improved without proportionally increasing process complexity. This parameter optimization resolves the contradiction between extent of cross-linking and process complexity.
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 proposed interpolymer composition results in improved cross-linking efficiency and mechanical properties, such as reduced hot-creep and increased dielectric breakdown voltage, leading to enhanced performance in cable insulation applications.
Implementation Method 1
polymerizing in a reaction zone ethylene with at least one type of non-conjugated diene comonomer in the presence of a free-radical initiator under conditions sufficient to effect incorporation
Implementation Method 2
The polyethylene can be any one or more of a number of various polyethylenes... are typically cross-linked, usually through the action of a peroxide initiator
Data Source
AI summary
Interpolymer resins having ethylene monomer residues and residues of a non-conjugated diene comonomer. The non-conjugated diene comonomer can be a dialkenyl phthalate. Incorporation of non-conjugated diene comonomers into interpolymers can provide additional labile unsaturation sites for cross-linking. The interpolymers and cross-linked variations thereof can be employed in a variety of articles of manufacture, such as, for example, as insulation material for power cables.