JPH0323887B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in reinforced optical fibers.

Usually, a primary coating made of plastic is provided around the outer periphery of the optical fiber, and a secondary coating or tertiary coating made of plastic or rubber is further provided around the outer periphery of this coating, but this is still effective in protecting the optical fiber. In addition, transmission loss increases due to temperature changes, etc., so it has been proposed to provide a reinforcing layer of glass fiber with a small coefficient of linear expansion and a resin impregnated with it and hardened as a secondary coating of the optical fiber. However, even with such conventional reinforcing layers, the following problems have been pointed out as issues that need to be improved.

In other words, conventionally, a reinforcing layer was formed by vertically attaching a large number of glass fibers to the outer periphery of a primary coated optical fiber, and impregnating and hardening a thermosetting resin between these glass fibers. In this case, the reinforcing layer is simply made of hard glass fibers arranged in the longitudinal direction of the optical fiber, so the mechanical properties such as strength against tensile loads and abrasion resistance can only be improved, and the reinforcement layer can withstand compressive loads and bending loads. Mechanical strength against such materials was insufficient.

As a result, problems such as minute scratches on the surface of the reinforcing layer grow due to the above-mentioned compressive load and bending load, causing cracks and destruction.

The present invention has been made to solve the above problems, and its configuration will be explained below with reference to the illustrated embodiments.

In a first embodiment of the present invention shown in FIG. 1, a reinforced optical fiber 1 includes an optical fiber 2 provided with a primary coating having cushioning properties, and a reinforcing layer 3 formed around the outer periphery of the optical fiber 2. It becomes more.

The above-mentioned reinforcing layer 3 consists of a large number of long fibers 4, 4, 4... attached longitudinally to the outer periphery of the optical fiber 2, and a resin 5 impregnated and hardened between each of these long fibers 4, 4, 4... , further, short fiber-like micro reinforcing elements 6, 6, 6, etc. are arranged inside the reinforcing layer 3 together with the resin 5 so as to be entangled with the respective long fibers 4, 4, 4...
It becomes more.

As each long fiber 4, 4, 4... in the above, glass filament with a fiber diameter of 20 μm or less is mainly used, and each of these long fibers 4, 4, 4...
It is preferable to vertically attach the fibers to the outer periphery of the optical fiber 1 in a roving state (number of filaments=several tens to hundreds of filaments).

On the other hand, the short fiber-like micro reinforcing elements 6, 6, 6... are also preferably made of glass, and the fiber length in this case is 5.
The fiber diameter may be equal to or different from the long fibers 4, 4, 4, . . .

On the other hand, as the resin 5, unsaturated polyester resin, epoxy resin, etc. are used.

Next, a second embodiment of the present invention will be explained with reference to FIG. 2. In the reinforced optical fiber 1 in this second embodiment, long fibers 4, 4, 4, . These long fibers 4, 4, 4... are impregnated and hardened with resin 5, and the long fibers 4, 4, in the same state are
Short fiber-like micro reinforcing elements 6,
6, 6... are arranged together with resin 5',
As a result, a reinforcing layer 3 is formed around the outer periphery of the optical fiber 2.

The difference between the first embodiment and this second embodiment is that the short fiber-like micro reinforcing elements 6, 6, 6... are located inside the reinforcing layer 3 or on the outer periphery. , resins 5 and 5' are made of the same material or thermosetting resin of the same type.

A known nylon coating or polyethylene coating may be provided directly or indirectly on the outer periphery of the reinforced optical fiber 1 constructed in this way, but a reinforcing outer layer 7 as shown in FIG. 3 may be provided on the outer periphery of the reinforcing layer 3. It is more preferable if

This reinforcing outer layer 7 is made of glass tape, glass roving, high Young's modulus carbon fiber, aramid fiber (for example, Kevlar manufactured by DuPont, USA) on the outer periphery of the reinforcing layer 3 configured as shown in FIGS. 1 and 2. )
A desired reinforcing material 8 is spirally wound or longitudinally attached, and a thermosetting resin 9 is impregnated into the reinforcing material 8 and hardened by impregnation and hardening.

The outer periphery of the reinforcing outer layer 7 constructed in this manner may be wrapped with glass thread for pressing or provided with a synthetic resin coating as described above, if necessary.

Note that the thermosetting resin 9 used here is
It may be made of the same material as the resins 5, 5' or may be made of a different material.

Next, the reinforced optical fiber 1 shown in each of the above embodiments
A manufacturing example will be explained with reference to FIG. 4 and the subsequent illustrations.

First, a manufacturing example of the reinforced optical fiber 1 shown in FIG. 1 will be explained with reference to FIG. 5. In this manufacturing example,
From the supply bobbin A of the optical fiber 2 and the supply bobbins B, B, B... of the long fibers 4, 4, 4... in a roving state, the optical fiber 2, long fibers 4, 4, 4... are respectively produced. Unwind and supply,
After passing these through the batten C, the optical fiber 2 and long fibers 4, 4, 4 are guided by guide rollers etc.
... is immersed in resin tank D.

This resin tank D contains liquid (uncured) resin 5.
are housed together with the micro-reinforcing elements 6, 6, 6..., and therefore the optical fibers 2 and long fibers 4, 4, 4... immersed in the resin bath D contain short fiber-like micro-reinforcing elements. 6, 6, 6... are attached together with the resin 5, and at this time, the long fibers 4, 4, 4..., which are in a roving state, are partially defibrated in the resin bath, so that short fiber-like microscopic particles are formed. Reinforcement element 6, 6, 6
... is combined with the long fibers 4, 4, 4..., and the resin 5 also spreads into the interior of the fibrillated state.

The optical fiber 2 and the long fibers 4, 4, 4, . Each long fiber 4, 4, 4...
The resin 5 passes through a molding die E with the resin surrounding it, and after passing through the die, it enters a heating type curing furnace F, where the resin 5 is thermally cured.

The reinforced optical fiber 1 manufactured through the steps up to thermosetting is then wound onto a winder G.

Next, a manufacturing example of the reinforced optical fiber 1 shown in FIG. 2 will be explained with reference to FIG. 5. In this manufacturing example,
The difference from the case shown in FIG. 4 is that two resin tanks D ₁ and D ₂ are used.

In other words, in the manufacturing example shown in FIG. 5, after the optical fiber ₂ and the long fibers 4, 4, 4, . Short fibrous micro reinforcing elements 6, 6, 6...
These optical fibers 2 and long fibers 4, 4, 4... are immersed in a resin tank _D2 containing...
The reinforced optical fiber 1 shown in FIG. 2 is then manufactured through a molding process using a die E and a resin curing process using a curing furnace F.

In addition, in the manufacturing example shown in Fig. 5, both resin tanks
A die and a curing furnace are also arranged between D ₁ and D ₂ , and the optical fiber 2 and the long fibers 4, 4, 4 are
The molding and resin curing may be carried out each time ... passes through the tanks D ₁ and D _2. In this case, the resin 5 is left in a semi-cured state after passing through the resin tank D ₁ . You can stay there.

Furthermore, the batten C in the above may be replaced with a normal guide roller, and in such a case, the die E
However, if dies and curing furnaces are placed after both resin tanks _D1 and _D2 , the battens will be placed only in front of the dies in the front stage. Ru.

Next, we will explain a manufacturing example in which up to the reinforcing outer tank 7 as shown in FIG. 3 is formed. In FIG. 6, supply bobbin A, supply bobbin B, B, B...
The optical fiber 2 and the long fibers 4, 4, 4, which have been rewound from Then, the same state as described in FIG. 4 is established.

Then, after passing the optical fiber 2, each long fiber 4, 4, 4... carrying the resin 5 and the short fiber-like micro reinforcing elements 6, 6, 6... through the batten C and the die E ₁ ,
The reinforcing material 8 is wrapped around the outer periphery of these pieces using the wrapping device H, and the resin 9 from the resin dripping device I is impregnated with the resin 9, and then the pieces in the same state are passed through the die E ₂ .
Further, the resins 5 and 9 are introduced into a curing furnace F to be cured.

In this way, a reinforced optical fiber 1 with a reinforcing outer layer 7 is produced, and the reinforced optical fiber 1 is wound onto a winder G.

The manufacturing example shown in FIG. 6 is suitable for wrapping the reinforcing material 8 made of glass tape or glass roving around a predetermined outer circumference, but it is suitable for forming the reinforcing material 8 made of glass tape into a cylindrical shape, for example. The result will be as shown in Figure 7.

In FIG. 7, the reinforcing material 8 unwound from the supply device J is once immersed in the resin tank D ₃ containing the resin 9, and then the resin 5 and the short fiber-like micro reinforcing elements 6, 6, 6... The reinforcing material 8 in the above state is added vertically to the outer periphery of the long fibers 4, 4, 4, etc. having
A molding process using E ₂ and a resin curing process using a curing furnace F are performed.

During this forming process, both side edges of the cylindrical reinforcing material 8 are overlapped or butted, but when they are butted, the reinforcing outer layer 7, which is mainly made of the reinforcing material 8, is It is best to wrap around the outer periphery with glass thread or the like.

Example 1 Long fibers 4, 4, 4, made of E glass filament, were attached vertically in the form of 18 rovings (310 tex) to the outer periphery of the optical fiber 2, which had an outer diameter of 0.4 mmφ after primary coating. These long fibers 4, 4,
4...Resin 5 consisting of unsaturated polyester inside,
E-glass filament (fiber length 3mm, fiber diameter 13μ)
mφ) short fibrous micro reinforcing elements 6, 6, 6
.

This reinforced optical fiber 1 has long fibers 4, 4, 4...
In addition to the tensile strength based on We were able to secure the necessary strength and satisfy the required strength overall.

Of course, no separation between the resin 5 and the long fibers 4, 4, 4, . . . that would cause a crack was observed.

Example 2 The reinforced optical fiber 1 shown in Fig. 1 was produced in the same manner as in Example 1 except that the long fibers 4, 4, 4...6 were in a roving state (160 tex), and the results were the same as in the previous example. Satisfactory strengths were secured.

Example 3 On the outer periphery of the same optical fiber 2 as in Example 1, six long fibers 4, 4, 4, . 4... is impregnated with a resin 5 made of unsaturated polyester, and on its outer periphery, a short fiber-like micro reinforcing element 6 made of E glass filament (fiber length 3 mm, fiber diameter 13 μmφ),
Resin 5' with 6,6... as unsaturated polyester
The reinforcing optical fiber 1 shown in Fig. 2 is laminated with a 2mm thick
Obtained with an outer diameter of φ.

In this case, both resins 5 and 5' were completely cured at the same time.

The various effects on strength were as satisfactory as in Example 1.

Example 4 The reinforced optical fiber 1 shown in FIG. 2 was produced in the same manner as in Example 3, except that the resin 5 was temporarily brought into a semi-hardened state, and then both resins 5 and 5' were completely hardened.

The effect on strength was almost the same as in Example 3.

Example 5 In order to form a reinforcing outer layer 7 on the outer periphery of the reinforcing layer 3 in the reinforced optical fiber 1 obtained in Example 1,
A reinforcing material 8 made of roving glass (160 tex, diameter 13 mmφ) was tightly wound spirally, and a resin 9 made of unsaturated polyester was impregnated and cured to obtain a reinforced optical fiber 1 with a reinforcing outer layer 7 as shown in Fig. 3. .

Note that the resin 5 of the reinforcing layer 3 and the resin 9 of the reinforcing outer layer 7
was cured at the same time.

The reinforced optical fiber 1 with the reinforcing outer layer 7 thus obtained had significantly improved strengths compared to each of the examples described above.

Example 6 In order to form a reinforcing outer layer 7 on the outer periphery of the reinforcing layer 3 in the reinforced optical fiber 1 obtained in Example 2,
A reinforcing material 8 made of glass tape (width 10 mm) impregnated with resin 9 is attached vertically, and this is rolled into a cylindrical shape, and a roving glass (E glass) with a diameter of 13 mmφ is further wrapped around the outer circumference to attach a reinforcing outer layer 7. A reinforced optical fiber 1 was obtained.

Note that the resin 5 of the reinforcing layer 3 and the resin 9 of the reinforcing outer layer 7
was cured at the same time.

The thus obtained reinforced optical fiber 1 with the reinforcing outer layer 7 had significantly improved strengths as in Example 5.

As mentioned above, the reinforced optical fiber of the present invention can ensure not only strong mechanical properties such as tensile strength and abrasion resistance, but also mechanical strength against bending load and compressive load. This can be sufficiently protected without reducing transmission characteristics.

[Brief explanation of drawings]

1 to 3 are cross-sectional explanatory views showing various embodiments of the reinforced optical fiber of the present invention, and FIGS. 4 to 7 are schematic explanatory views showing manufacturing examples of each of the above-mentioned reinforced optical fibers. 1... Reinforced optical fiber, 2... Optical fiber, 3
...Reinforcement layer, 4...Long fiber, 5,5'...Resin,
6...Short fibrous micro reinforcing element.

Claims (1)

[Scope of Claims] 1. On the outer periphery of the optical fiber, a plurality of long fibers are arranged along the longitudinal direction of the optical fiber, and a plurality of short fiber-like micro reinforcing elements are arranged to intertwine with each of the long fibers,
A reinforced optical fiber characterized in that a reinforcing layer made of impregnated and hardened resin is provided between each of the fibers. 2. The reinforced optical fiber according to claim 1, wherein the plurality of short fiber-like micro reinforcing elements are inside the reinforcing layer. 3. The reinforced optical fiber according to claim 1, wherein the plurality of short fiber-like micro reinforcing elements are located on the outer periphery of the reinforcing layer.