JPH0738884Y2 - Single-core optical fiber code - Google Patents

Description

[Detailed Description of the Invention] "Industrial application field" The present invention relates to a single-core optical fiber cord that is drawn out for wiring to a device from a terminal end of an optical fiber cable body, and particularly, it is intended to improve heat resistance. It also relates to a single-fiber optical fiber cord.

[Background of the Invention] Usually, as shown in FIG. 1, a single-core optical fiber cord is provided with a tensile strength member 2 on the outer circumference of an optical fiber core wire 1 and a sheath 3 covering the outer circumference thereof.

Such a single-fiber optical fiber cord has an advantage that it is easy to manufacture and use.

In the conventional single-core optical fiber cord, a tensile strength member 2 made of poly-P-phenylene terephthalamide fiber (hereinafter abbreviated as PPPTA) is provided on the outer periphery of an optical fiber core wire 1 coated with nylon. The outer circumference is covered with a sheath 3 made of polyvinyl chloride (PVC). This single-core optical fiber cord has a maximum operating temperature of + 60 ° C.
It is considered as a degree. Therefore, in the single-core optical fiber cord used in a high temperature atmosphere, the FRP is attached to the outer periphery of the strength member 2.
It has been practiced to provide a coating layer made of (1) and to apply a sheath 3 made of a heat resistant resin to the outer periphery thereof.

However, this single-fiber optical fiber cord has the problems that it takes time to manufacture and the flexibility of the cord is impaired.

In order to deal with such a problem, the tensile strength member 2 of the single-core optical fiber cord having the structure shown in FIG. 1 is formed of PPPTA, and the sheath 3 is formed of an appropriate heat-resistant material, which facilitates manufacturing. It has been proposed to obtain a single-fiber optical fiber cord that is easy to use and has excellent heat resistance.

However, in the process of developing the single-core optical fiber cord having heat resistance of +100 to 190 ° C, the present inventors actually manufactured the single-core optical fiber cord by combining PPPTA and various heat-resistant resins as shown in Table 1. However, there were the following problems.

PFA: Polyfluoroalkoxy resin FEP: Tetrafluoroethylene / hexafluoropropylene copolymer PVF ₂ : Polyvinylidene fluoride ETFE: Ethylene / tetrafluoroethylene copolymer First, in No. 1, after leaving it in an atmosphere of 150 ° C Returning to room temperature causes a significant loss increase.

No. 2 and No. 4 have a problem that the core wire 1 is bent due to contraction of the sheath 3 material when the sheath 3 is covered (contraction when the molten state is solidified = molding contraction), increasing the initial transmission loss. There is. There is also a problem that the transmission loss increases due to temperature changes and the transmission loss increases at high temperatures.

In No. 3 and No. 5, the core wire 1 is bent more than that in No. 2 and No. 5 at the time of coding, the initial transmission loss is greatly increased, and the temperature characteristic and the high temperature characteristic are deteriorated.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a single-fiber optical fiber cord that has little increase in initial transmission loss due to coding, is excellent in temperature characteristics and high temperature characteristics, and is easy to manufacture and use. To aim.

"Means for Solving Problems" Therefore, in the present invention, a tensile strength member made of polyparaphenylene / 3,4 'diphenyl ether terephthalamide (hereinafter abbreviated as PPDPETA) is provided on the outer periphery of the optical fiber core, The above problem was solved by coating the outer circumference with a sheath made of trifluoroethylene chloride resin.

Hereinafter, the single-fiber optical fiber cord of the present invention will be described in detail.

The cross-sectional structure of this single-core optical fiber cord is similar to that shown in FIG.

The sheath 3 of this single-core optical fiber cord has a temperature range of -60 ° C to +18.
Trifluoroethylene chloride (PCTFE), which has excellent heat resistance to withstand continuous use at 0 ° C and excellent chemical resistance
Is formed by.

Moreover, the tensile strength member 2 of this single-core optical fiber cord is PPDP.
It is made of ETA fibers. PPDPETA has a structure represented by the following formula (1), and this fiber has high strength and has both heat resistance and chemical resistance.

The core wire 1 of the single-core optical fiber cord is secondarily coated with a resin having a melting point higher than the extrusion temperature of the material forming the sheath 3. As mentioned above, the sheath material is PCTFE.
Is used, and the extrusion temperature of this PCTFE is 300 ℃ ~
Since the temperature is about 330 ° C., it is desirable to use the secondary coating material of the core wire 1 having a melting point of about 300 ° C. or higher. An example of such a secondary coating material is polyfluoroalkoxy (PFA) having a melting point of 310 ° C.

[Examples] Hereinafter, the single-core optical fiber cord of the present invention will be described with reference to Examples.

The single-fiber optical fiber cord of the present invention was prepared with the specifications shown in Table 2. For comparison, the strength member 2 is PPPTA.
The single-fiber optical fiber cords of Comparative Examples 1 and 2 formed in 1. were prepared. The outer diameter of the core wire 1 is 0.8 mm, and the outer diameter of the strength member 2 is
The diameter was 1.5 mm and the cord outer diameter was 2.3 mm.

The transmission loss in the state of the core wire 1 and the transmission loss in the coded state were examined for each prototyped optical fiber code. Also, when the cord is placed in a heat cycle environment of -20 ° C + 60 ° C x 10 cycles, the maximum transmission loss change amount at the maximum temperature, the minimum temperature, and the high temperature atmosphere (+150
Maximum transmission loss change at ℃) in high temperature atmosphere (+150
The maximum transmission loss change was investigated when the temperature was lowered from (° C) to room temperature (+ 20 ° C). The measurement wavelength was 0.85 μm. The results are shown in Table 3.

As shown in Fig. 2, it is generally recognized that PPPDETA is inferior in heat shrinkage property to PPPTA, but from the results shown in Table 3, the tensile strength member 2 is formed of PPPDETA and the sheath 3 is formed. The single-fiber optical fiber cord of the present invention formed of PCTFE has an extremely small increase in transmission loss due to coding, and undergoes a temperature change, as compared with the one in which the strength member 2 is formed of PPPTA. It was found that the amount of change in transmission loss was extremely small even when used in a high temperature atmosphere or when the temperature dropped from high temperature to room temperature.

When each single-fiber optical fiber cord used in the test was disassembled and examined, the cords of Comparative Examples 1 and 2 showed contraction of the PPPTA tensile strength member 2. In particular, in the cord of Comparative Example 2, when the sheath 3 was coated, the secondary coating of the core wire 1 was softened and contracted to cause bending of the core wire 1, which confirmed the increase in transmission loss due to the coding.

Next, the tensile strength of the optical fiber cord of the prototyped example was measured at high temperature (+ 150 ° C) and low temperature (-20 ° C).
Tensile strength is measured by chuck spacing of 500 mm, pulling speed of 5 mm / m
I went in. For comparison, the tensile strength of a general single-fiber optical fiber cord was measured at room temperature (+ 20 ° C.). The specifications of the single-core optical fiber cord of the comparative example are as follows. Core wire secondary coating: Nylon, tensile strength body 2: Kevlar (trade name; made by DuPont) as PPPTA, sheath 3: polyvinyl chloride.
The dimensional specifications are the same as in the example. Table 4 shows the results of the tensile strength when the single core cord is elongated by 1%.

From the results shown in Table 4, it was confirmed that the optical fiber cord of the present invention can be used in a wide temperature range from high temperature to low temperature in terms of strength.

[Effect of the Invention] As described above, in the single-core optical fiber cord of the present invention, a tensile strength member made of PPDPETA is provided on the outer circumference of the optical fiber core wire, and a sheath made of trifluoroethylene chloride resin is provided on the outer circumference thereof. Since it is coated, the increase in initial transmission loss due to coding is extremely small, and the transmission loss due to temperature change and the amount of change in transmission loss at high temperatures are also small.
It has excellent heat resistance and can be used even at high temperatures.

Moreover, since the single-core optical fiber cord of the present invention has the same structure as a general single-core optical fiber cord in which a tensile strength member and a sheath are sequentially provided around the core wire, it can be easily manufactured.

Therefore, according to the present invention, it is possible to provide a single-fiber optical fiber cord that is excellent in heat resistance, temperature characteristics, and high temperature characteristics, and that is easy to manufacture and easy to use.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a single-core optical fiber cord, and FIG. 2 is a graph showing the relationship between the temperature of PPPDETA and PPPTA and the shrinkage ratio. 1 ... Core wire, 2 ... tensile body, 3 ... sheath.

Claims (1)

[Scope of utility model registration request] 1. A tensile strength member made of polyparaphenylene.3,4'-diphenyl ether terephthalamide is provided on the outer circumference of an optical fiber, and a sheath made of trifluorochloroethylene resin is coated on the outer circumference thereof. A single-core optical fiber cord.