Self-Extinguishing Cable Coating to Prevent Flaming Drips
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Solution Overview
Problem
Current flame-retardant cables require high quantities of fillers like magnesium hydroxide and aluminium hydroxide to achieve effective flame retardation, leading to increased viscosity, decreased productivity, and impaired mechanical properties, while still allowing for flaming droplet formation during fires, which complicates certification and manufacturing.
Innovation Solution
A low-smoke zero-halogen (LSOH) flame-retardant cable with a polymer composition comprising less than 170 phr of metal hydroxide, 1 to 10 phr of phyllosilicate clay, at least 1 phr but less than 10 phr of melamine or its derivative, and 20 to 70 phr of alkali or alkaline-earth metal carbonate, which significantly reduces dripping and maintains mechanical properties during fires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large quantities of flame-retardant fillers (170-200 phr of metal hydroxide) are added to achieve satisfactory flame retardation and self-extinguishing properties, then flame-retardant effectiveness is improved, but viscosity increases considerably and extrusion speeds decrease significantly, leading to drop in productivity
Solution Approach 1:
The patent changes the concentration parameters of flame-retardant additives, reducing metal hydroxide to less than 170 phr and combining it with other flame-retardant agents in specific proportions to achieve effective flame retardation without excessive filler amounts that would increase viscosity and reduce extrusion speed
Solution Approach 2:
The patent uses a composite flame-retardant system combining multiple agents (metal hydroxide, phosphorus-containing flame retardant, nitrogen-containing flame retardant, and synergistic agent) rather than relying on a single filler, achieving effective flame protection with reduced overall filler content and better processability
2Reliability
If high quantities of flame-retardant additives (170-200 phr of metal hydroxide) are added to achieve flame-retardant properties, then flame propagation resistance is improved, but mechanical properties of the cable deteriorate substantially
Solution Approach 1:
The patent optimizes the concentration of metal hydroxide to less than 170 phr and balances it with other flame-retardant agents in specific ratios, maintaining flame propagation resistance while avoiding the mechanical property deterioration caused by excessive filler content
Solution Approach 2:
The patent employs a composite flame-retardant system where multiple agents work together synergistically, reducing the need for high quantities of any single filler and thereby preserving the mechanical integrity of the cable while achieving effective flame propagation resistance
3Reliability
If large amounts of flame-retardant filler are used to prevent flaming droplet formation, then self-extinguishing properties are improved, but manufacturing cost increases and mechanical features are impaired
Solution Approach 1:
The patent adjusts the concentration of flame-retardant agents to optimized levels (metal hydroxide less than 170 phr combined with phosphorus-containing, nitrogen-containing, and synergistic agents in specific proportions), achieving effective self-extinguishing properties without the need for excessive filler amounts that would impair mechanical features and increase manufacturing cost
4Reliability
If high quantities of filler are added to achieve flame retardation, then flame-retardant performance is improved, but the viscosity of the material increases and cable workability decreases
Solution Approach 1:
The patent optimizes the concentration of fillers by reducing metal hydroxide to less than 170 phr and balancing it with other flame-retardant agents, maintaining effective flame-retardant performance while keeping material viscosity at acceptable levels to ensure good cable workability during manufacturing
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 solution effectively prevents flaming droplets during fires, meets stringent certification standards, and ensures good workability and mechanical properties, particularly in extrusion processes, without the need for excessive filler amounts.
Implementation Method 1
a cable provided with a flame-retardant and self-extinguishing coating layer made from a polymer composition comprising at least one metal hydroxide as filler and a combination of flame-retardant aids based on phyllosilicate clay, melamine derivative and metal carbonate
Implementation Method 2
at least one metal hydroxide as filler... which confer flame-retardant properties to a cable coating layer
Data Source
Figure 1~2
Figure 3~4
AI summary
1. A flame-retardant cable (10;20;30;40) is disclosed, the cable having a core comprising at least one conductor (11;41), and a coating (13a;14;43a) made from a low smoke zero halogen flame-retardant polymer composition comprising a halogen free base polymer added with: a) less than 170 phr of at least one metal hydroxide; b) from 1 to 10 phr of a phyllosilicate clay; c) at least 1 phr and less than 10 phr of melamine or a derivate thereof; and d) an alkali or alkaline-earth metal carbonate. Such a cable has improved reaction to fire performances, especially absence of dripping during burning, which render it compliant with the requirements of the more recent international standards.