Drop Cable Jacket Composition for Low Shrink and Small Bend
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Solution Overview
Problem
Conventional optical fiber cables experience buckling due to thermal expansion and contraction, leading to signal attenuation and premature degradation, and require slow processing speeds due to the use of stiff glass fibers for antibuckling.
Innovation Solution
A flexible tensile element made of thermoplastic elastomers and high aspect ratio fillers, combined with a low CTE exterior jacket, allows for improved bend performance and faster processing speeds by shifting antibuckling functions to the exterior jacket.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If glass fibers are used for antibuckling, then cable stability is improved, but processing speed deteriorates
Solution Approach 1:
The patent changes the material parameters of the tensile element from traditional stiff glass fibers to a composite material with specific properties: thermoplastic elastomer matrix (providing flexibility) combined with high aspect ratio fillers (providing antibuckling strength). This parameter change enables both fast processing speeds and effective antibuckling performance.
Solution Approach 2:
The patent employs a composite material structure for the tensile element, combining thermoplastic elastomer with high aspect ratio fillers. The elastomer provides flexibility for high-speed processing while the fillers provide the structural rigidity needed for antibuckling, thus resolving the contradiction between processing speed and cable stability.
2Stability of the object's composition
If stiff glass fibers are used, then antibuckling performance is improved, but bend performance deteriorates
Solution Approach 1:
The patent modifies the physical parameters of the tensile element by using a composite material with controlled stiffness. The thermoplastic elastomer matrix provides flexibility for good bend performance, while the high aspect ratio fillers maintain sufficient rigidity for antibuckling performance.
Solution Approach 2:
The composite structure of thermoplastic elastomer and high aspect ratio fillers creates a material that exhibits both flexibility (for bend performance) and structural stability (for antibuckling), resolving the contradiction between these two performance requirements.
3Ease of manufacture
If conventional cable jacket materials are used, then ease of manufacture is improved, but thermal expansion control deteriorates
Solution Approach 1:
The patent modifies the thermal properties of the cable jacket by incorporating a specific composition with controlled coefficient of thermal expansion (CTE). The jacket material is formulated to have a CTE that matches or complements the optical fiber, reducing thermal expansion/contraction differences that cause buckling, while maintaining ease of manufacture through extrusion processes.
Solution Approach 2:
The cable jacket uses a composite material formulation that combines polymers with specific thermal expansion characteristics. This composite approach allows control over the CTE parameter to minimize thermal buckling while maintaining manufacturability through standard extrusion techniques.
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 solution provides improved antibuckling and bend performance while enabling processing speeds up to 300 m/min, reducing production costs and enhancing cable durability.
Implementation Method 1
Because of their exposure to hot and cold temperatures, the cable jacket expands and contracts, which causes cable buckling
Implementation Method 2
the cable jacket expands and contracts
Data Source
Figure 1~2
Figure 3~4
AI summary
Embodiments of an optical fiber cable are provided. The optical fiber cable includes at least one optical fiber, a buffer tube surrounding the at least one optical fiber, and at least one tensile element wound around the buffer tube. The at least one tensile element has a laylength of at least 200 mm. The optical fiber cable also includes an exterior jacket surrounding the tensile element. The exterior jacket is made up of at least one polyolefin, at least one thermoplastic elastomer, and at least one high aspect ratio inorganic filler. Further, the exterior jacket has an averaged coefficient of thermal expansion of no more than 120(10-6) m/mK.