Frp tension member for drop optical fiber cable

Abstract

To resolve blister formation phenomenon. Drop optical fiber cable (1) comprises core optical fibers (2,3), tension member (4), supporting wire (5) and main body coating (6). The tension member (4) consists of an FRP tension member having an FRP portion comprising reinforcing fibers bound together with a thermosetting resin. In the FRP tension member, it is required for the residual styrene monomer content of the FRP portion to be 0.018 wt.% or less (based on the weight of FRP portion). When the amount of residual styrene monomer exceeds the above content, for example, contact with molten main body coating thermoplastic resin would occur during the main body coating step of the drop optical fiber cable production process to thereby cause evaporation of residual styrene monomer, resulting in abnormalities, such as blistering, in the coating portion or main body coating portion. Controlling of the content of residual styrene monomer so as to be given value or below can be accomplished by selections of highly reactive thermosetting resin and highly reactive catalyst, securement of curing time, post-treatment after curing, etc.

Description

technical field [0001] The present invention relates to a drop optical fiber cable obtained by coating an optical fiber core wire and a tensile member together with a thermoplastic resin, especially a non-metallic drop optical fiber cable capable of reducing weight and diameter Tensile body made of FRP. Background technique [0002] With the advent of the information society, the capacity of transmission information such as the Internet has increased, and FTTH, in which optical cables are also laid for users such as buildings and houses, has been rapidly developed. [0003] As a drop cable for FTTH, the idea of ​​using a metal wire for the tension member is proposed, for example, in Patent Document 1 (JP-A-2001-337255). However, when a metal wire is used as the tension body, it must be grounded in order to avoid the shock pulse caused by lightning. In order to achieve grounding, it requires a lot of time and effort in construction, and with it, construction costs have to b...

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Problems solved by technology

[0009] That is, according to the production method disclosed in the above-mentioned Patent Document 2, for example, when glass fiber is used as a reinforcing fiber, unsaturated polyester is used as a thermosetting resin, and polyethylene is used for coating, there is a problem that the rod-shaped product obtained The bonding strength is 106kg / cm 2 (10MPa), the coated surface is not necessarily smooth, and it is difficult to obtain a uniform and thin diameter

[0011] However, in the FRP tensile body disclosed in this patent application, when actually manufacturing the drop cable, the main body coating of the FRP tensile body with a thermoplastic resin is performed at a relatively low speed depending on the manufacturing conditions. , and when the main body is coated in a temperature range slightly higher than the extrusion temperature, due to the phenomenon of foaming of the coating part, problems of poor appearance and adverse effects on the optical fiber occur.

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