Halogen-Free Optical Fiber Coating for Flame Retardancy

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Solution Overview

Problem

Existing optical fiber cables face challenges in achieving high flame retardancy while maintaining lightweight features and mechanical strength, particularly in indoor and vehicle applications, due to the use of halogen-containing resins which can lead to environmental contamination and additive migration affecting light transmission efficiency.

Innovation Solution

A halogen-free resin composition comprising polyolefin resin and a melt tension enhancer, combined with a halogen-free flame retardant, is used to form a multilayered coating for optical fiber cables, ensuring excellent flame retardancy and mechanical characteristics without increasing transmission loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogen-containing resins are used to achieve flame retardancy, then flame retardancy is improved, but environmental contamination and additive migration affecting light transmission efficiency occur

Engineering Contradiction:
Improveflame retardancyVSAvoidenvironmental contamination and additive migration
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the coating material by specifying precise ratios of polyolefin resin (70-99 mass%), melt tension enhancer (1-30 mass%), and halogen-free flame retardant (5-60 mass%). This parameter optimization enables achieving flame retardancy without halogen-containing resins, thereby eliminating environmental contamination and additive migration issues while maintaining light transmission efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating material combining polyolefin resin, melt tension enhancer, and halogen-free flame retardant in specific proportions. This composite formulation achieves the desired flame retardancy through synergistic effects while avoiding the harmful properties of halogen-containing resins, thus resolving the contradiction between flame retardancy and environmental contamination.

Inventive Principle:
Principle #40Composite materials

2Reliability

If flame retardant coating material is applied to optical fiber, then flame retardancy is improved, but transmission loss increases

Engineering Contradiction:
Improveflame retardancyVSAvoidtransmission loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies different functional properties to different components of the coating material: polyolefin resin provides mechanical strength and chemical stability, melt tension enhancer prevents dripping during combustion, and halogen-free flame retardant provides flame retardancy. This local functional assignment allows achieving flame retardancy while minimizing interference with light transmission, thus reducing transmission loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent optimizes the concentration ranges of each component in the coating material to balance flame retardancy and light transmission properties. By controlling the mass percentage of polyolefin resin (70-99%), melt tension enhancer (1-30%), and halogen-free flame retardant (5-60%), the patent achieves flame retardancy while minimizing transmission loss through precise parameter control.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If heavy flame retardant materials are used to achieve high flame retardancy, then flame retardancy is improved, but mechanical strength and lightweight features are compromised

Engineering Contradiction:
Improveflame retardancyVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the physical and chemical parameters of the coating material by selecting specific polymer types and their ratios. Using polyolefin resin with controlled molecular weight and combining it with melt tension enhancer and halogen-free flame retardant in optimized proportions achieves high flame retardancy while maintaining mechanical strength and lightweight characteristics, avoiding the need for heavy flame retardant materials.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent develops a composite coating system where polyolefin resin provides mechanical strength, melt tension enhancer provides fire resistance through melt dripping prevention, and halogen-free flame retardant provides flame retardancy. This composite approach achieves high flame retardancy without compromising mechanical strength or increasing weight, as each component contributes efficiently to the overall performance.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2977806B1Optical-fiber cable
Publication Date: 2016.11.16 MITSUBISHI CHEM CORP

AI summary

An optical fiber cable is formed with an optical fiber and a coating layer made up of at least one layer provided on the outer periphery of the optical fiber. The material for forming the coating layer is made of a halogen-free resin composition containing polyolefin resin (A) and melt tension enhancer (B).