Polyurethane Overmold for Fiber Optic Cable Splicing Protection
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Solution Overview
Problem
The existing methods for manufacturing optical cable assemblies with branch lines create vulnerabilities in the protective jacket, leading to mechanical and environmental damage, and are costly and time-consuming, especially when splicing occurs in the field.
Innovation Solution
A polyurethane composition is developed, comprising a first part of a first polytetramethylene oxide, a second polytetramethylene oxide with higher viscosity, a castor oil-based polyol, and methylene diphenyl diisocyanate, which is used to create an overmold that protects the splicing location of fiber optic cable assemblies, providing enhanced mechanical and environmental protection without the need for flame-treating the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If field splicing is performed to create branch lines, then cable assembly flexibility is improved, but mechanical strength and reliability deteriorate due to vulnerabilities in the protective jacket
Solution Approach 1:
The patent applies preliminary action by pre-positioning branch line vulnerabilities at predetermined locations during manufacturing, allowing branch lines to be created at factory-defined points rather than requiring field splicing. This maintains protective jacket integrity while enabling cable assembly flexibility through pre-planned branching points.
Solution Approach 2:
The patent implements beforehand cushioning by creating controlled vulnerabilities at predetermined locations during manufacturing, which are then protected by strategic placement of strength members and protective structures at these known weak points. This approach cushions against future damage by anticipating where vulnerabilities will occur and preparing protective measures in advance.
2Adaptability or versatility
If field splicing is performed to create branch lines, then cable adaptability is improved, but manufacturing cost and time consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-positioning branch line vulnerabilities at predetermined locations during manufacturing, allowing branch lines to be created at factory-defined points rather than requiring field splicing. This maintains protective jacket integrity while enabling cable assembly flexibility through pre-planned branching points.
Solution Approach 2:
The patent replaces the mechanical field splicing process with a manufacturing-phase approach where branch lines are created during cable assembly production using controlled vulnerabilities and automated placement of protective components, eliminating the need for manual field splicing operations.
3Ease of manufacture
If traditional polyurethane formulations are used for overmolds, then material availability is improved, but bonding strength and environmental resistance worsen
Solution Approach 1:
The patent applies parameter changes by modifying the polyurethane formulation to include specific ratios of polyether polyols (20-50 parts), ester polyols (30-60 parts), and extender polyols (10-30 parts), along with controlled amounts of catalysts and processing aids. These parameter adjustments optimize both bonding strength and environmental resistance while maintaining manufacturing feasibility.
Solution Approach 2:
The patent implements composite materials by creating a multi-component polyurethane system that combines different types of polyols (polyether, ester, and extender) with diisocyanate, catalysts, and processing aids. This composite formulation achieves superior bonding strength and chemical resistance compared to traditional single-component polyurethanes.
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 polyurethane overmold exhibits strong bonding with the cable jacket, excellent mechanical and chemical resistance, and flexibility across a wide temperature range, significantly reducing the risk of damage and maintaining integrity under various environmental conditions.
Implementation Method 1
a polyurethane composition is provided. The polyurethane composition includes a first part of a first polytetramethylene oxide, a second polytetramethylene oxide, and a castor oil based polyol... a second part of methylene diphenyl diisocyanate
Implementation Method 2
The polyurethane overmold exhibits strong bonding with the cable jacket
Data Source
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AI summary
A polyurethane composition is provided. The polyurethane composition includes a first part of a first polytetramethylene oxide, a second polytetramethylene oxide, and a castor oil based polyol. The second polytetramethylene oxide has a higher viscosity than the first polytetramethylene oxide. The polyurethane composition also includes a second part of methylene diphenyl diisocyanate. Also provided is a fiber optic cable assembly incorporating the polyurethane composition as an overmold. The overmold has a glass transition temperature of less than -40 C measured according to differential scanning calorimetry. Further provided is a method of applying an overmold to a fiber optic cable assembly.