JP2001305399A - Plastic optical fiber cable and wire harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic optical fiber cable having satisfactory mechanical strength even in the case of a smaller diameter, excellent in flexibility and formable into a harness with an electric wire and to provide a wire harness comprising the plastic optical fiber cable and an electric wire. SOLUTION: The plastic optical fiber cable is obtained by disposing a primary coating layer 2 comprising a polyamide resin containing a titanate or glass filaments on a plastic optical fiber 1 and further coating the surface of the layer 2 with a secondary coating layer 3 comprising a flame retardant polyethylene or polyvinyl chloride. The wire harness is obtained by bundling the plastic optical fiber cable and an electric wire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic optical fiber cable and a wire harness formed by bundling a plastic optical fiber cable and an electric wire.

[0002]

2. Description of the Related Art Conventionally, a wire harness (see FIG. 2) formed by bundling a plurality of electric wires has been generally used for wiring in a building or connection between various devices of an automobile. On the other hand, in recent years, in order to transmit more signals,
Optical fiber cables have become widespread for such applications.
In particular, in connection with control systems and display systems in automobiles and information communication devices in buildings, optical fiber cables are becoming the mainstream in place of conventional electric wires.

[0003] Among optical fiber cables, an optical fiber cable using a plastic optical fiber is more flexible than a silica-based optical fiber cable, has a large diameter and a high numerical aperture, and has an end face treatment. Due to its simplicity and the like, it is being used for light transmission over a relatively short distance, such as routing in a car. As shown in FIG. 4, for example, this plastic optical fiber cable generally comprises a plastic optical fiber 1 which is sequentially coated with a primary coating layer 10 and a secondary coating layer 11. The primary coating layer 10 is provided for improving heat resistance and mechanical strength, and is generally formed of a resin having excellent heat resistance and mechanical properties such as tensile strength such as polyamide resin. is there. The secondary coating layer 11 is provided for imparting flame retardancy, and is made of, for example, polyvinyl chloride or flame-retardant polyethylene resin. The secondary coating layer 11 is generally formed to be thick for the purpose of suppressing transmission loss due to lateral pressure, limiting the minimum bending radius, and suppressing transmission loss at the time of biting.

[0004]

However, in recent years,
There has been an increasing demand for smaller diameter plastic optical fiber cables, and for that purpose, the thickness of the primary coating layer 10 and the secondary coating layer 11 must be reduced. However, if the primary coating layer 10 is made thin, the heat resistance and mechanical strength become insufficient. Therefore, it is necessary to provide the secondary coating layer 11 with heat resistance and mechanical strength to compensate for the shortage. For this reason, a polyamide resin is also used for the secondary coating layer 11, and an appropriate flame retardant is blended into the resin to make it flame-retardant.

[0005] However, while the polyamide resin is excellent in mechanical strength, it is less flexible than polyvinyl chloride, polyethylene or the like. Therefore, a plastic optical fiber cable using the flame-retardant polyamide resin as the secondary coating layer 11 is not available. Becomes less cordy. In particular, the difference in flexibility is greater than that of electric wires, and it is extremely difficult to combine them with electric wires to make them into a honey, and to arrange this plastic optical fiber cable separately from a wire harness that usually consists only of electric wires. The current situation is searching for.

The present invention has been made in view of such circumstances, and has a sufficient mechanical strength even if the diameter is reduced, and is excellent in flexibility and capable of forming a harness with an electric wire. It is an object to provide a fiber cable and a wire harness including the plastic optical fiber cable and an electric wire.

[0007]

In order to achieve the above object, the present invention provides a plastic optical fiber with a primary coating layer comprising a titanate or a polyamide resin containing a glass filament, and further comprising: A plastic optical fiber cable characterized in that a primary coating layer is coated with a secondary coating layer made of flame-retardant polyethylene or polyvinyl chloride.

Further, in order to achieve the same object, the present invention provides a wire harness comprising the above plastic optical fiber cable and electric wires bundled.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. The plastic optical fiber cable according to the present invention is provided with a primary coating layer 2 made of a polyamide resin containing titanate or a glass filament on a plastic optical fiber 1 as shown in a sectional view in FIG. Further, the primary coating layer 2 is formed by coating a secondary coating layer 3 made of flame-retardant polyethylene or polyvinyl chloride.

The plastic optical fiber 1 is not particularly limited, and is made of, for example, a conventionally known methyl methacrylate homopolymer or a copolymer of methyl methacrylate and another copolymerizable monomer. . As copolymerizable monomers, for example, methyl acrylate,
Ethyl acrylate, acrylates such as n-butyl acrylate, methacrylates such as ethyl methacrylate, propyl methacrylate, cyclohexyl methacrylate, maleimides, acrylic acid, methacrylic acid, maleic anhydride, styrene and the like. And one or more of these can be selected. When a copolymer is used, 50% or more is preferably methyl methacrylate.

The polyamide resin forming the primary coating layer 2 is not particularly limited, and a conventionally known polyamide resin can be appropriately selected and used. For example, polyamide 12 can be suitably used. The primary coating layer 2 contains a titanate or a glass filament. When blending glass filaments, the blending amount is preferably 25 to 30% by weight based on the total amount with the polyamide resin. In addition, as a glass filament,
Alkali glass and high-strength glass (T glass) for electrical insulation
A fiber obtained by cutting a fiber made of the same into an appropriate length can be used. Among the titanates, potassium titanate is particularly preferred, and the amount thereof is preferably 10 to 30% by weight based on the total amount of the polyamide resin. If the blending amount of both the glass filament and potassium titanate is less than the lower limit, sufficient mechanical strength cannot be obtained, and it is not possible to cope with a reduction in diameter. On the other hand, when the compounding amount exceeds the upper limit, the amount of the polyamide resin is relatively small, and the heat resistance is inferior. Also, in order to prevent light leakage from the fiber of the cable, it is conceivable to make the coating color dark, but since potassium titanate is a white powder, the coloring property deteriorates when the blending amount increases,
Because it turns white, it is no longer suitable for its intended purpose. Furthermore, since both the glass filament and the titanate are solid substances, the surface of the primary coating layer 2 becomes rough when the amount of the glass filament and the titanate is large, and the surface is liable to be damaged by abrasion or the like during winding or wiring.

By mixing glass filaments or titanate, the primary coating layer 2 has enhanced mechanical strength as compared with the case of using only the polyamide resin alone, and realizes a narrower cable. Specifically, in a plastic optical fiber cable for car wiring using a plastic optical fiber wire having a diameter of 1 mm, in order to obtain a specified breaking strength, a layer thickness of about 0.4 mm in the case of polyamide 12 alone is used. What was necessary can be reduced in thickness to about 0.25 mm by blending potassium titanate. As described above, it is presumed that the reason why the mechanical strength is enhanced by blending the glass filament or the titanate is that the extrusion temperature can be increased as compared with the case where the polyamide resin is used alone. That is,
The extrusion temperature of polyamide 12 alone is usually from 220 to 230.
C., whereas the polyamide 12 containing glass filaments or titanate has an extrusion temperature of 24 ° C.
It is considered that the temperature can be increased to about 5 to 260 ° C., and as a result, the adhesion to the plastic optical fiber is increased and the mechanical strength is increased.

The flame-retardant polyethylene or polyvinyl chloride for forming the secondary coating layer 3 may be a known one. These resins have higher flexibility than polyamide resins, and have an effect of increasing the flexibility of the entire cable in the present invention. In order to impart flame retardancy to polyethylene, for example, a flame retardant such as a metal hydroxide may be blended. However, if the blending amount of the flame retardant increases, the flexibility decreases. It is preferable to suppress. Also,
It is preferable that a coloring agent is blended in the secondary coating layer 3 for identification.

The plastic optical fiber cable of the present invention formed as described above can realize a reduction in diameter because the primary coating layer 2 has high mechanical strength in addition to heat resistance.
Accordingly, the flexibility of the entire cable can be improved by using a resin having excellent flexibility for the secondary coating layer 3.

The present invention also provides a wire harness in which the above-mentioned plastic optical fiber cable and electric wires are bundled. That is, as shown in FIG. 2, the wire harness 20 is connected to the plastic optical fiber cable 21 described above.
(Here, one) and electric wires (here, two) 22, 22
Are bundled with a tape 24. Further, connectors 23 are respectively attached to both ends of the plastic optical fiber cable 21 and the electric wires 22 and 22.

As described above, the conventional plastic optical fiber cable has low flexibility, and it is extremely difficult to form a harness integrally with the electric wire and route it together with the electric wire. By using the cable 21, the difference in flexibility from the electric wire 22 is reduced, and it is possible to form a harness and arrange the electric wire 22 together with the electric wire 22. As a result, it is only necessary to route the plastic optical fiber cable and the electric wire once, and the routing operation can be greatly simplified.

[0017]

EXAMPLES The present invention will be further clarified with reference to examples.

(Measurement of Breaking Strength) As shown in Table 1, a molding material was prepared by mixing and kneading polyamide 12 with varying amounts of potassium titanate, and an outer diameter shown in Table 1 was formed on a 1 mm diameter plastic optical fiber. The coating thickness was adjusted and extruded to form a coating layer, and a test plastic optical fiber cable was manufactured. The polyamide 12 alone was extruded at 220 ° C., and the polyamide 12 containing potassium titanate was extruded at 260 ° C.

The breaking strength of each test plastic optical fiber cable was measured using a Shimadzu autograph under the conditions of a load cell of 1000 N and a tensile speed of 100 mm / min. The results are also shown in Table 1.

[0020]

[Table 1]

From Table 1, it was found that potassium titanate was 10% by weight.
It can be seen that the blending greatly increases the breaking strength regardless of the wire diameter (coating thickness). A similar test was conducted for a molding material containing potassium titanate in an amount exceeding 30% by weight. However, no significant difference was observed in the breaking strength when potassium titanate was added in an amount of 30% by weight. In addition, when an optical fiber cable was produced using a black coating material containing potassium titanate in an amount exceeding 30% by weight, the gloss was reduced and the appearance became slightly grayish.

(Evaluation of Flexibility) 10 wt% of potassium titanate was placed on a plastic optical fiber having a diameter of 1 mm.
0.25 mm thick 1 made of blended polyamide 12
A test coating optical fiber cable (product of the present invention) was produced by providing a secondary coating layer and further providing a secondary coating layer of polyvinyl chloride having a thickness of 0.25 mm thereon. For comparison, a 0.4 mm thick primary coating layer of polyamide 12 was provided on a 1 mm diameter plastic optical fiber, and a 0.25 mm thick secondary coating layer of polyamide 12 was further formed thereon. And a test plastic optical fiber cable (conventional product) was manufactured.

Then, 1 m of each test plastic optical fiber cable was cut out into a test piece, and the test piece was first stretched in warm water to remove the curl, and then the diameter was 35 mm.
Wrap about 0.8m around the cylinder, and make it horizontal and 4
A load of 50 g was attached. After maintaining this state for 30 minutes, the plastic optical fiber cable was detached from the cylinder, and one end thereof was fixed and suspended in the air as shown in FIG. 3, and the droop length (L) was measured. Note that reference numeral F in the drawing indicates a plastic optical fiber cable. The droop length (L) was measured immediately after the cylinder was removed (0 minutes) and 30 minutes after the cylinder was removed. Table 2 shows the results.

[0024]

[Table 2]

As shown in Table 2, the product of the present invention has already returned from the spiral state to the linear state by about half immediately after the removal of the cylinder, whereas the conventional product maintains the spiral state. After 30 minutes, the product of the present invention almost returned to a straight line, whereas the conventional product still returned to a straight line only about 70%. This indicates that the product of the present invention easily changes its shape and is excellent in flexibility.

[0026]

As described above, according to the present invention,
A plastic optical fiber cable having sufficient mechanical strength even with a small diameter, excellent flexibility, and a harness with an electric wire can be obtained. In addition, a wire harness between the plastic optical fiber cable and the electric wire can be obtained, and the wiring work can be simplified.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a plastic optical fiber cable according to the present invention.

FIG. 2 is a perspective view showing a wire harness obtained by bundling a plastic optical fiber cable and electric wires according to the present invention.

FIG. 3 is a diagram for explaining a measurement method used for evaluating flexibility in an example.

FIG. 4 is a sectional view showing a conventional plastic optical fiber cable.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plastic optical fiber 2 primary coating layer 3 secondary coating layer 20 wire harness 21 plastic optical fiber cable 22 electric wire 23 connector 24 tape

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 11/22 H01B 11/22 F term (Reference) 2H001 BB02 FF02 KK03 KK22 2H050 AB42Z AC71 BA34 BB15R BB22Q 5G309 AA04 5G319 HA08 HB05 HB10 HC05 HE02 HE13

Claims (3)

[Claims] 1. A primary coating layer made of a polyamide resin containing titanate or glass filament is provided on a plastic optical fiber, and a flame-retardant polyethylene or polyvinyl chloride is provided on the primary coating layer. A plastic optical fiber cable which is coated with a secondary coating layer made of: 2. The plastic optical fiber cable according to claim 1, wherein the titanate is potassium titanate and is blended in the primary coating layer at a ratio of 10 to 30% by weight. 3. A wire harness comprising a bundle of the plastic optical fiber cable according to claim 1 and an electric wire.