Crosslinked Cable Covering Composition for Shrinkback Resistance
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Solution Overview
Problem
Cables with coverings crosslinked by silane processes suffer from shrinkback when exposed to high temperatures or fast extrusion line speeds, leading to exposed conductive elements and system failures, and existing solutions do not adequately address this issue while maintaining ambient temperature curing efficiency.
Innovation Solution
A cable covering composition comprising a blend of polyethylene and 10-20% polyolefin elastomer, such as ethylene-octene copolymer, combined with a silane coupling agent, which is crosslinked to prevent shrinkback and improve curing at ambient temperatures, meeting industry standards like UL 44 ed. 19 (2018).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silane crosslinking processes are used to form cable coverings, then crosslinking simplicity and low manufacturing cost are achieved, but shrinkback occurs when exposed to high temperatures or fast extrusion line speeds
Solution Approach 1:
The patent modifies the polymer composition parameters by incorporating specific polyethylene-polyolefin elastomer blends (10-20% polyolefin elastomer content) to change the thermal and mechanical properties of the covering material, enabling it to resist shrinkback while maintaining crosslinking simplicity
Solution Approach 2:
The patent creates a composite material system combining polyethylene base polymer with polyolefin elastomer additives and silane coupling agents, where each component contributes specific properties: polyethylene provides structural basis, polyolefin elastomer provides shrinkback resistance, and silane enables crosslinking
2Reliability
If polyethylene-polypropylene blend is used to reduce contraction, then some shrinkback reduction is achieved, but adequate shrinkback prevention at high temperatures is not sufficient
Solution Approach 1:
The patent changes the polymer blend composition from polyethylene-polypropylene to polyethylene-polyolefin elastomer with specific ratios (10-20% elastomer content), which fundamentally alters the thermal response characteristics and enables adequate shrinkback resistance at high temperatures
Solution Approach 2:
The patent adopts and improves upon the concept of using polymer blends for shrinkback reduction, copying the approach from Goncalves but replacing polypropylene with polyolefin elastomers to achieve superior high-temperature performance
3Productivity
If conventional polymer compositions are used, then standard extrusion processes are maintained, but ambient temperature curing efficiency is insufficient
Solution Approach 1:
The patent introduces silane coupling agents as intermediary substances that enable crosslinking reactions to proceed efficiently at ambient temperatures, acting as a bridge between the polymer chains and facilitating curing without requiring high temperature or pressure conditions
Solution Approach 2:
The silane coupling agents are incorporated into the polymer composition during compounding, performing preliminary preparation for crosslinking before the actual extrusion and curing processes, enabling ambient temperature curing to occur efficiently
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 composition significantly reduces shrinkback and achieves improved curing at ambient temperatures, passing the Hot Creep Test at 150° C. and Deformation Test, ensuring the cable meets strict qualifications and maintains performance without excessive leakage or system failures.
Implementation Method 1
Silane crosslinking processes are often employed to effect such crosslinking because of their relative simplicity and low manufacturing costs
Data Source
AI summary
A cable includes cable one or more conductors and a covering surrounding the one or more conductors. The covering is formed from a composition including polyethylene and a polyolefin elastomer, where the composition is crosslinked. A method of forming the cable is also provided.