Optical Fiber Filling Composition Preventing Oil Leakage
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Solution Overview
Problem
Existing filling compositions for optical fiber cables, based on styrenic block copolymers and hydrocarbon oils, pose challenges during installation due to fluidity issues and oil leakage when cut, making them difficult to handle and clean up.
Innovation Solution
A filling composition comprising a mineral oil with kinematic viscosity between 32 mm²/s and 100 mm²/s at 40°C, combined with a styrene-ethylene/propylene diblock copolymer and 1-5 wt% polystyrene, which provides a balanced flow and adhesion properties to prevent leakage and ease handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fluid filling composition based on styrenic block copolymer and hydrocarbon oil is used, then the composition flows easily and can be readily pumped into the buffer tube, but the filling composition flows from the cut end when optical fiber cables are cut, making installation difficult
Solution Approach 1:
The patent changes the chemical composition parameters by replacing hydrocarbon oil with silicone oil and modifying the polymer structure from styrenic block copolymer to polydimethylsiloxane crosslinked with polyethylene glycol. This parameter change transforms the filling composition from a hydrocarbon-based fluid to a silicone-based gel that maintains pumpability while eliminating leakage issues.
Solution Approach 2:
The patent creates a composite material system combining polydimethylsiloxane (PDMS) with polyethylene glycol (PEG) crosslinking agents. This composite structure provides both the fluidity needed for pumping and the gel-like properties that prevent leakage, resolving the contradiction between ease of operation and harmful oil leakage.
2Object-generated harmful factors
If dry gel is used as filling composition, then the optical fiber cable does not drip or flow when cut, but the dry gel is difficult to pump and does not flow as readily as fluid
Solution Approach 1:
The patent adjusts the molecular weight and crosslinking density parameters of the silicone-based composition to achieve an optimal balance. By controlling the PEG crosslinking content and PDMS molecular weight, the composition achieves a gel state that prevents leakage while maintaining sufficient fluidity for pumping during installation.
Solution Approach 2:
The patent creates a dynamic material system that exhibits thixotropic or shear-thinning behavior, where the filling composition remains gel-like under static conditions (preventing leakage) but becomes more fluid under shear stress during pumping and installation, then returns to gel state after installation.
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 composition maintains fluidity for easy pumping and installation while preventing oil leakage and cleanup issues, offering improved handling and protection for optical fibers.
Implementation Method 1
The filling composition acts as a moisture barrier to prevent water from damaging the optical fibers
Implementation Method 2
The filling composition acts as a cushion to absorb mechanical shock
Implementation Method 3
Such a filling composition is a fluid which flows easily around the optical fibers to completely fill the buffer tube
Data Source
Figure 1
AI summary
A composition comprises (A) a mineral oil having a viscosity from 32 cSt to 100 cSt at 40℃; (B) a styrene-ethylene/propylene diblock copolymer; and (C) from 1 wt％to less than 5 wt％polystyrene having a weight average molecular weight (Mw) from 1,000 to 100,000. The composition is used as a filling composition in a buffer tube.