Multilayer Halogen-Free Optical Fiber Cable Jacket

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Solution Overview

Problem

Existing optical fiber cables face challenges in achieving effective fire protection without complex manufacturing steps, as traditional single-material layer cable jackets are insufficient in preventing fire propagation.

Innovation Solution

A multilayered cable jacket design using two or more layers of flame-retardant materials with different modes of action, such as intumescent-acting materials and mineral fillers, to enhance fire protection performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional single-material layer cable jacket is used, then manufacturing process is simple, but fire protection performance is insufficient

Engineering Contradiction:
Improvefire protection performanceVSAvoidcable jacket structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining multiple flame-retardant material layers with different fire protection mechanisms (intumescent-acting materials, mineral fillers, phosphorous and/or nitrogen gas phase active materials) to create a multilayered cable jacket that provides enhanced fire protection performance through synergistic effects of different materials

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The cable jacket is segmented into multiple layers, each with specific thickness and material composition, allowing different flame-retardant mechanisms to operate at different levels and provide comprehensive fire protection that a single homogeneous layer cannot achieve

Inventive Principle:
Principle #1Segmentation

2Reliability

If traditional cable materials are replaced with high performance flame-retardant materials, then fire protection performance improves, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveflame retardant protectionVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple flame-retardant material layers into a unified cable jacket structure that can be manufactured using conventional extrusion techniques, combining the fire protection benefits of different material types while maintaining compatibility with existing manufacturing infrastructure

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent optimizes parameters such as layer thickness, material composition ratios, and extrusion conditions to achieve high fire protection performance while ensuring the multilayered structure can be produced using traditional manufacturing methods without requiring completely new production lines

Inventive Principle:
Principle #35Parameter changes

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 multilayered structure provides 100% halogen-free, non-corrosive, high flame retardant protection, effectively delaying and slowing down cable combustion, and preventing fire from reaching the cable core.

Implementation Method 1

The different flame-retardant additives included in a base material of the various layers of the cable jacket may include intumescent-acting materials

Methodology Applied
Scientific EffectIntumescent action: Intumescent Materials

Implementation Method 2

materials to provide an inorganic barrier protection or other highly filled materials

Methodology Applied
Scientific EffectHeat absorption and dehydration: Mineral Hydration

Implementation Method 3

phosphorous and/or nitrogen gas phase active materials

Methodology Applied
Scientific EffectGas phase flame inhibition:

Data Source

PatentEP3540487B1Optical fiber cable with improved fire protection performance
Publication Date: 2025.03.05 CORNING RES & DEV CORP
  • EP3540487B1 patent drawingFigure 1
  • EP3540487B1 patent drawingFigure 2
  • EP3540487B1 patent drawingFigure 3

AI summary

An optical fiber cable (10, 20, 30, 40, 50) comprises a cable core (100) including at least one optical transmission element (110) to transfer light, and a cable jacket (200) surrounding the cable core (100). The cable jacket (200) is embodied as a multilayered structure having a first sheath layer (210) and at least a second sheath layer (220) being surrounded by the first sheath layer (210). The material of the first and the second sheath layer (210, 220) is halogen free. The material of the first sheath layer (210) and the material of the second sheath layer (220) have a different flame retardant additive providing different flame retardant mechanisms.