Fire-Resistant Cable Using Phosphonate-Silicon Oxide Fillers
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Solution Overview
Problem
Current fire-resistant cable technologies face challenges in achieving effective flame retardation, mechanical flexibility, and cost efficiency, particularly due to the high quantities of fillers required and the toxicity of halogenated compounds, which also impact productivity and mechanical properties.
Innovation Solution
A fire-resistant cable with an electrically insulating layer composed of an organic polymer matrix dispersed with a silicon oxide macromolecular network functionalized by phosphonate functions, formed through a sol-gel process, eliminating the need for additional fillers and ensuring uniform dispersion within the polymer matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large quantities of metal hydroxide fillers are incorporated to achieve satisfactory fire resistance, then flame retardation efficiency is improved, but viscosity of the material increases considerably and extrusion speed decreases
Solution Approach 1:
The invention changes the chemical composition and molecular structure of the flame retardant from simple metal hydroxides to macromolecular network fillers with silicon oxide backbone and phosphonate functions. This structural parameter change allows the filler to provide equivalent or superior fire resistance at much lower quantities (5-50 parts by weight versus 150-250 parts by weight of metal hydroxides), thereby maintaining extrusion speed and productivity.
Solution Approach 2:
The invention uses composite macromolecular network fillers combining silicon oxide framework with phosphonate functional groups, creating a synergistic structure where silicon oxide provides thermal stability and phosphonate groups enhance flame retardation efficiency. This composite structure achieves superior fire resistance at lower filler loadings compared to simple metal hydroxides, resolving the contradiction between fire resistance and extrusion productivity.
2Reliability
If excessive amounts of fire retardant additives are added to improve flame retardation, then fire resistance is improved, but mechanical and electrical properties of the cable deteriorate significantly
Solution Approach 1:
The invention changes the filler morphology from fine metal hydroxide particles to macromolecular network structures with larger molecular weight and three-dimensional architecture. This parameter change reduces the total filler quantity needed while maintaining fire resistance, thereby preserving the polymer matrix integrity and mechanical properties.
Solution Approach 2:
The macromolecular network filler structure mimics and reinforces the polymer matrix structure rather than disrupting it. The silicon oxide network acts as a structural analog to the organic polymer chains, creating a hybrid network that maintains mechanical integrity while providing fire resistance at lower loadings.
3Reliability
If halogenated compounds are used to improve fire resistance, then flame retardation efficiency is improved, but toxicity and corrosiveness increase
Solution Approach 1:
The invention replaces harmful halogenated compounds with benign phosphonate-functionalized silicon oxide fillers. The phosphonate groups provide effective flame retardation through a different mechanism (forming protective char layers and releasing phosphoric acid) that does not produce toxic halogenated gases, thus converting the harmful halogen-based approach into a beneficial halogen-free alternative.
Solution Approach 2:
The silicon oxide macromolecular network creates an inert protective barrier during combustion, forming a stable char layer that prevents oxygen access to the polymer matrix and releases non-toxic substances. This inert environment approach replaces the reactive toxic mechanism of halogenated compounds with a safe, non-corrosive flame retardation system.
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 provides excellent fire resistance, mechanical flexibility, and cost-effectiveness by uniformly dispersing the flame-retardant filler within the polymer matrix, meeting fire resistance standards while maintaining good mechanical properties.
Implementation Method 1
formed through a sol-gel process
Implementation Method 2
flame-retardant filler comprising a macromolecular network of silicon oxide functionalized by phosphonate functions
Data Source
Figure 1
AI summary
The invention relates to a fire-resistant cable comprising an electrically insulating fire-resistant layer comprising an organic polymer matrix in which a flame-retardant filler comprising a macromolecular network of silicon oxide functionalized by phosphonate functions is dispersed, the electrically insulating layer being obtained from a composition comprising at least one organic thermoplastic polymer and at least one precursor of said flame-retardant filler comprising silicon and phosphorus; and also to a process for preparing said cable.