Microduct Optical Cable Sheath for Flame Retardancy and Air Blowing
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Solution Overview
Problem
The challenge is to develop an optical cable with high flame retardancy and good air-blowing performance for installation in microducts, which are small-diameter ducts, while reducing installation costs and increasing blowing distance.
Innovation Solution
The optical cable features a sheath layer with a density of 2.0 g/cm3 or less, composed of an olefin-based resin, silicone, and a non-halogen flame retardant, with specific mass ratios and molecular weights, enhancing flame retardancy and air-blowing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the sheath layer uses conventional materials with high flame retardancy, then flame safety is improved, but the density increases and air-blowing performance deteriorates
Solution Approach 1:
The sheath layer uses a composite material system comprising a polyolefin resin base material combined with specific flame retardant additives. This composite approach achieves high flame retardancy (passing vertical combustion test) while maintaining low density (2.0 g/cm³ or less), resolving the contradiction between flame safety and air-blowing performance in microduct installation.
Solution Approach 2:
The patent optimizes the density parameter of the sheath layer to 2.0 g/cm³ or less through careful selection of polyolefin resin and flame retardant combinations. This parameter change enables the cable to achieve both high flame retardancy and good air-blowing performance, allowing installation in small-diameter microducts without sacrificing safety.
2Length of moving object
If the sheath layer density is reduced to improve air-blowing performance, then blowing distance is improved, but flame retardancy may deteriorate
Solution Approach 1:
By using composite materials consisting of polyolefin resin with optimized flame retardant additives, the patent achieves the dual benefit of low density (improving blowing distance) and high flame retardancy. The composite structure allows the sheath layer to pass vertical combustion tests while maintaining density at 2.0 g/cm³ or less for effective microduct installation.
Solution Approach 2:
The patent employs cost-effective polyolefin resin materials that provide sufficient flame retardancy for indoor installation requirements while maintaining low density. This approach achieves the necessary safety performance without excessive cost, enabling widespread deployment in FTTH networks.
3Object-affected harmful factors
If the sheath layer uses flame retardant materials, then flame safety is improved, but the cable weight increases affecting installation efficiency
Solution Approach 1:
The patent optimizes the sheath layer density parameter to 2.0 g/cm³ or less through selective use of polyolefin resin and flame retardant combinations. This parameter optimization reduces cable weight for improved installation efficiency while maintaining high flame safety standards for indoor use.
Solution Approach 2:
The composite material system of polyolefin resin with flame retardant additives provides high flame safety (passing vertical combustion test) without significantly increasing cable weight. This composite approach enables the cable to meet safety requirements while maintaining light weight for efficient installation in microducts.
Data Source
AI summary
An optical cable according to an embodiment of the present disclosure is an optical cable for installation in a microduct, the optical cable including one or more optical-fiber core wires, and a sheath layer covering an outer peripheral side of the one or more optical-fiber core wires. The sheath layer has a density of 2.0 g/cm3 or less. The sheath layer contains an olefin-based resin, a silicone, and a non-halogen flame retardant. A mass ratio of the non-halogen flame retardant to the olefin-based resin is 0.90 to 2.00. A mass ratio of the silicone to the olefin-based resin is 0.005 to 0.100. The olefin-based resin contains a polyethylene, and an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer. The silicone has a weight-average molecular weight of 50,000 to 1,000,000.