Optical Fiber Cable LBL Coating for Flame Retardance Without Bulk Fillers
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Solution Overview
Problem
Optical fiber cables face challenges in incorporating sufficient flame retardant materials without degrading mechanical properties or increasing cable thickness, especially in small diameter cables where size constraints limit the amount of filler needed for enhanced flame retardant performance.
Innovation Solution
A layer-by-layer (LBL) flame retardant coating technique is applied using positively and negatively charged ionic solutions to form multiple thin layers on the cable components, such as the jacket and buffer tubes, enhancing flame retardance without compromising mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flame retardant filler materials are incorporated into cable components, then flame retardant performance is improved, but mechanical properties of the polymer are degraded
Solution Approach 1:
The flame retardant functionality is segmented from the structural polymer matrix. Instead of mixing filler materials throughout the polymer, the invention applies a separate flame retardant coating layer on the surface of the cable components, dividing the system into structural and protective functional layers.
Solution Approach 2:
The flame retardant filler materials are extracted from the polymer bulk and placed in a separate coating layer. This extraction eliminates the degradation of mechanical properties caused by filler incorporation while maintaining flame retardant performance through the dedicated coating layer.
2Reliability
If the thickness of cable components is increased to provide sufficient flame retardant material, then flame retardant performance is improved, but the overall cable thickness increases
Solution Approach 1:
The invention uses thin film coatings applied to the surface of cable components to provide flame retardant protection. These thin films deliver sufficient flame retardant performance without requiring increases in the base cable component thickness, thereby maintaining compact cable dimensions.
3Reliability
If the thickness of cable components is increased to incorporate enough filler material, then flame retardant performance is improved, but the cable size increases
Solution Approach 1:
The invention creates a composite structure consisting of the base polymer component and an applied flame retardant coating layer. This composite approach concentrates flame retardant materials in a thin external layer rather than dispersing them throughout the bulk, achieving high flame retardant performance with minimal volume increase.
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 LBL coating provides significant flame retardant performance while maintaining the cable's mechanical integrity and reducing the overall cable size by minimizing the need for thick, highly filled polymer components.
Implementation Method 1
a flame retardant coating having at least one layer is applied to one or both of the jacket outer surface of the cable jacket or the outer buffer tube surface of the buffer tube... the polymeric component is sprayed with at least one coating sequence including a polycation spray, water, a polyanion spray, and water
Data Source
AI summary
Disclosed herein are embodiments of an optical fiber cable. The optical fiber cable includes a cable jacket having a jacket inner surface and a jacket outer surface in which the jacket inner surface defines a central bore extending along a longitudinal axis of the optical fiber cable. The optical fiber cable also includes a buffer tube having an inner buffer tube surface and an outer buffer tube surface, and the buffer tube is disposed within the central bore of the cable jacket. At least one optical fiber is disposed within the buffer tube. A flame retardant coating having at least one layer is applied to one or both of the jacket outer surface of the cable jacket or the outer buffer tube surface of the buffer tube.