PBT Buffer Tube Flame Retardant Composition

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Solution Overview

Problem

Current flame retardant compositions for optical fiber cables compromise mechanical properties, making installation difficult and failing to meet stringent flame retardancy standards like B2 rating.

Innovation Solution

A flame retardant composition comprising 70-90 wt% PBT resin, 15-25 wt% flame retardant additive, ethylene vinyl alcohol (EVOH), and an organoclay synergist, with optional PBT chain extenders or reactive compounds, is used to create buffer tubes that maintain mechanical properties while achieving B2 rating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional flame retardant compositions are used to achieve flame retardancy, then flame retardant performance is improved, but mechanical properties deteriorate

Engineering Contradiction:

Improveflame retardancyVSAvoidmechanical properties

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent employs a composite material system comprising PBT resin as base polymer, dialkylphosphinic salt as flame retardant additive, organoclay synergist for enhanced flame resistance, and EVOH for mechanical property enhancement. This multi-component composite achieves B2 flame rating while maintaining mechanical integrity through synergistic interactions between components

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the concentration parameters of each component within specific ranges: PBT resin (70-90 wt%), dialkylphosphinic salt (15-25 wt%), and controlled amounts of organoclay synergist and EVOH. This parameter optimization ensures adequate flame retardancy while preserving mechanical properties by preventing excessive additive loading that would compromise structural integrity

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If flame retardant additives are added to achieve B2 rating, then flame retardant performance is improved, but installation difficulty increases

Engineering Contradiction:

Improveflame retardant performanceVSAvoidinstallation ease

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent maintains the PBT resin content at 70-90 wt% within the composition, ensuring the buffer tube retains the flexibility and mechanical properties necessary for easy installation and handling, while still achieving B2 flame rating through the optimized flame retardant system

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The inclusion of EVOH (ethylene vinyl alcohol) in the composite formulation specifically addresses mechanical property enhancement, providing the buffer tube with adequate toughness and flexibility for installation while maintaining the flame retardant performance through the dialkylphosphinic salt and organoclay synergist system

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20250208364A1Flame retardant compositions for buffer tubes and method of making same

Publication Date: 2025.06.26 CORNING RES & DEV CORP

AI summary

Embodiments of the disclosure relate to a flame retardant composition. The flame retardant composition includes 70 wt % to 90 wt % of at least one polybutylene terephthalate (PBT) resin, 15 wt % to 25 wt % of a flame retardant additive, an ethylene vinyl alcohol (EVOH), an organoclay synergist, and at least one of a PBT chain extender having epoxide functional groups or a reactive compound including at least two functional groups selected from the group consisting of an epoxide, a maleic anhydride, an isocyanate, an acrylate, and an acetate. The flame retardant composition is particularly suitable for buffer tubes of optical fiber cables.