JP2000047076A - Spacer for optical fiber cable and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the tensile performance of a PFRP tensile strength body of a spacer for a optical fiber cable. SOLUTION: This spacer 10 is provided with: a tensile strength body 15 consisting of a PFRP line 12 formed with PBO fiber as reinforcing fiber, and a primary coating layer 14 formed on the outer periphery of the PFRP line 12 from a thermoplastic resin; first, second and third preparatory coating layers 16, 17 and 18, separately and successively formed in three stages on the outer periphery of the primary coating layer 14, in that order; and a spacer main body coating layer 20 formed on the periphery of the third preparatory coating layer 18; wherein grooves 22 each of which has a specific shape and is used for receiving optical fiber, are formed in the spacer main body coating layer 20 and also, in order to secure the strength of the PFRP line, the thickness of the first preparatory coating layer 16 is adjusted to <=2 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for an optical fiber cable and a method for manufacturing the same, and more particularly to a technique for improving the tensile performance of the spacer.

2. Description of the Related Art An optical fiber cable is provided with an electric field in the vicinity of a high-voltage power line in order to secure work safety.
In order to prevent the cable member from being affected by the magnetic field, it is required to make the cable member non-metallic (non-metallic).

[0002] If a non-metallic material such as FRP is used instead of a metal tensile strength member such as a steel wire having a large specific gravity, the weight can be reduced and the cable laying length can be extended.
It also contributes to labor saving of construction and reduction of construction cost.

[0003] Such a non-metallic cable strength member is required to have a high tensile property, so
FRP (hereinafter, sometimes referred to as PFRP) using polyparaphenylene benzobisoxazole (hereinafter, referred to as PBO) fibers having a tensile modulus of not less than 00 kg / mm ² as reinforcing fibers is suitable.

[0004]

However, in a spacer using PFRP as a tensile strength member, flexibility can be greatly improved by reducing the outer diameter of the FRP, and workability of laying a cable has been improved. The property, that is, the tensile performance, tended to decrease as compared with the tensile performance calculated from the tensile modulus of the PBO fiber.

[0005] The reason for this is that when pre-coating is performed to secure the groove shape on the outer periphery of the tensile strength member, or when the spacer body is coated to form the groove, the heat generated by cooling and solidification of the melt-extruded coating portion. It is conceivable that the contraction causes a compressive force to act in the longitudinal direction of the tensile strength member, and that the PFRP receives a compressive stress.

That is, even if a conventional PFRP wire is used as a tensile strength member, the stress at the time of 0.2% elongation, which is an important specification of an optical fiber cable, is reduced, and there is a problem that the optical fiber cannot be effectively protected. Was.

[0007] Accordingly, the present inventors have made intensive studies to provide a spacer for an optical fiber cable using a PFRP wire as a tensile strength member and having excellent tensile performance, and completed the present invention.

[0008]

According to the present invention, there is provided an optical fiber cable spacer comprising a tensile member disposed at the center and a spiral groove formed of a thermoplastic resin on the outer periphery. Uncured FRP in which uncured thermosetting resin impregnated with polyparaphenylene benzobisoxazole (PBO) fiber is impregnated with thermoplastic resin on the body, and the inside of the uncured FRP is formed with thermoplastic resin. It is obtained by curing a thermosetting resin and has an apparent tensile modulus of 800, which can be calculated from the stress value at 0.2% elongation.
0 kg / mm ² or more. Further, the optical fiber cable spacer of the present invention, a preliminary coating layer is applied to the outer periphery of the primary coating layer of the tensile strength member in a plurality of times,
The first thickness can be 2 mm or less. Further, in the optical fiber cable spacer of the present invention, the PBO fiber volume content of the PFRP can be set in the range of 67 to 69%. Further, as an even more preferable physical property range of the tensile strength member, an apparent tensile elastic modulus which can be calculated from a stress value at 0.2% elongation is 10,000 kg.
/ Mm ² or more. According to the production method of the present invention, a predetermined number of PBO fibers are impregnated with a thermosetting resin, which is drawn and formed into an uncured filament, and then guided to a head portion of a melt extruder. A primary coating is formed in a ring shape with a molten thermoplastic resin, which is immediately cooled, and then the internal thermosetting resin is heat-cured in a heat-curing tank. The primary coating layer having a thickness of 2 mm or less is formed on the outer periphery of the primary coating layer. After pre-coating with a resin compatible with the thermoplastic resin of
The spacer body is coated with a thermoplastic resin.

[0009]

Embodiments of the present invention will be described below. In the present invention, a polyparaphenylene benzobisoxazole (PBO) fiber having a high tensile modulus is used as the reinforcing fiber of the FRP tensile strength line.

[0010] By using PBO fibers, PBO fibers can be used.
Because the fiber has a high tensile modulus, the required fiber cross-sectional area can be reduced, and as a result, the diameter and weight of the FRP can be reduced.

Further, a thermosetting resin is used as a matrix resin for binding the reinforcing fibers, and the thermosetting resin is
Unsaturated polyester resin, vinyl ester resin is generally used, but epoxy resin, phenol resin, etc. may be used, and a catalyst such as peroxide is added to these resins,
Impregnated into PBO reinforcing fibers.

If a vinyl ester resin is used as the matrix resin, the heat resistance of the FRP can be improved.

Impregnating the PBO reinforcing fiber with a thermosetting resin,
After drawing to a predetermined outer diameter, it is annularly coated with a molten thermoplastic resin to obtain an uncured FRP single wire provided with a primary coating layer.

As the thermoplastic resin of the primary coating layer, a resin having compatibility with the thermoplastic resin of the preliminary coating layer applied to secure the shape accuracy of the spiral groove prior to the subsequent coating of the spacer body is selected. The coating thickness is approximately 0.5
１．５1.5 mm.

[0015] If the coating thickness is less than 0.5 mm, there is a risk that the uncured resin inside leaks through pinholes and the like,
If it exceeds 1.5 mm, there is a problem that the material is partially cured by heat at the time of forming the primary coating layer, and the physical properties of FRP are reduced.

Further, the preliminary coating layer and the spacer main body coating layer need to be fused to each other in order to maintain strength, and from this viewpoint, those having mutual compatibility are selected.

When the assumed outer diameter of the groove bottom of the spacer body is about 1.3 times the outer diameter of the primary coating layer and the groove of the spacer body coating is a shallow groove, the preliminary coating is not necessarily required, and The spacer body may be coated.

For the primary coating layer, low density polyethylene (L
DPE) is preferred in that it easily anchor-bonds at the interface of the PFRP, and the pre-coating layer and the spacer main body coating layer are polyethylene-based resins such as high-density polyethylene (hereinafter referred to as HDPE) because of their excellent low-temperature properties. Is generally recommended.

Further, a PF having a cured primary coating layer
When applying the preliminary coating layer to the outer periphery of the RP, the thickness of the first coating layer needs to be 2 mm or less.

When the thickness of the pre-coating layer exceeds 2 mm, P
This is because a heat shrinkage force accompanying the cooling and solidification of the preliminary coating layer acts on the FRP, thereby applying a compression force to the PFRP, thereby lowering the tensile modulus.

The reason why the apparent tensile modulus, which can be calculated from the stress value at 0.2% elongation of the tensile strength member, is 8000 kg / mm ² or more, is to secure the tensile strength required as an optical cable.

That is, in order to effectively protect and support the optical fiber when a tension acts on the optical cable, it is necessary to use a 0.1.
It is necessary to develop a predetermined stress at 2% elongation, and from this point, a tensile elastic modulus of 8000 kg / mm ² or more is required.

The apparent tensile elastic modulus at the time of 0.2% elongation is a constant-speed elongation type tensile tester (Shinko Co., Ltd.) equipped with a load cell having a load of 2,000 kg and holding both ends of an 800 mm sample at 100 mm. ) Made by TOM), 5m
A tensile test was performed at m / min, and the tension was calculated from the slope of a straight line connecting the zero point of the load-elongation curve and the stress measurement point at 10.2% elongation.

The PBO fiber volume content of PFRP is more preferably in the range of 67 to 69% in order to secure the tensile performance.

When the volume content of the PBO fiber is within this range, it is preferable in that the tensile modulus is further improved.

Further, polyparaphenylene benzobisoxazole (PBO) fiber is used as a reinforcing fiber, and an apparent tensile elastic modulus which can be calculated from a stress value at 0.2% elongation is 1000.
0 kg / mm ² is preferable in that the tensile performance is further improved.

In the manufacturing method of the present invention, a predetermined number of P
The BO fiber is impregnated with a thermosetting resin, which is drawn and formed into an uncured filament, then led to the head of a melt extruder, and its outer periphery is primarily coated with a molten thermoplastic resin in an annular shape. This is immediately cooled, and then the thermosetting resin inside is thermoset in a thermosetting bath.

In order to prevent the curing, the primary coating layer is formed by guiding the uncured FRP to the guide jacket attached to the head of the melt extruder through cooling water, and to the outer periphery of the head of the melt extruder to prevent curing. From an annular die having a discharge opening larger than the outer diameter of the uncured FRP to be coated, the molten thermoplastic resin is extruded in a drawn-down state, and the coated cone is brought into contact with the uncured FRP at a point where the inner diameter of the coated cone comes into contact with the uncured FRP. By guiding and cooling the primary coating layer, the surface and the like of the uncured resin inside will not start partially curing.

Subsequently, the uncured P having the primary coating layer
The FRP is passed through a heat-curing bath to cure the resin inside. The temperature is increased by using high-pressure steam as a heat medium for curing.
When the temperature is near the softening point of the thermoplastic resin of the primary coating layer, FR
The outer circumference of the FRP and the inner circumference of the primary coating layer undergo flow contact under pressure in combination with the heat generated by the curing of P, so that after curing, the PFRP and the primary coating layer can be in a state of being anchor-bonded to each other. The performance as a tensile strength member in the obtained spacer is ensured.

The pre-coating layer is applied to the outer periphery of the primary coating layer after the PFRP is cured. The coating thickness of the first-stage pre-coating layer is set to 2 mm or less for the above-mentioned reason. Pre-coat with a resin compatible with the resin.

The pre-coating is performed according to the groove depth of the spacer to be obtained.
As described in Japanese Patent No. 81763, in order to adjust the outer diameter to a predetermined outer diameter in relation to the assumed outer diameter of the groove bottom, it is performed a plurality of times as necessary.

After appropriately adjusting the outer diameter of the preliminary coating layer,
A spacer main body having a groove having a predetermined size and shape on the outer periphery is applied with a thermoplastic resin compatible with the preliminary coating layer.

In the present invention, to cover in a ring shape means to cover in a closed shape without a seam. less than,
The present invention will be described with reference to a preferred embodiment.

Embodiments Embodiment 1 FIG. 1 shows the cross-sectional shape of the optical fiber cable spacer of the present embodiment.

The spacer 10 shown in FIG. 1 includes a tensile strength member 15 composed of a PFRP wire 12 having PBO fiber as a reinforcing fiber, a primary coating layer 14 of a thermoplastic resin on the outer periphery thereof, and a thermoplastic resin on the outer periphery of the primary coating layer. The spacer main body coating layer 20 is applied to the outer periphery of the first, second, and third preliminary coating layers 16, 17, 18 and the third preliminary coating layer 18 which are divided into three stages, and the optical fiber housing having a predetermined shape is accommodated. Groove 22 was formed. In order to secure the strength of PFRP, the thickness of the first preliminary coating layer 16 was set to 2 mm or less. More specifically, the optical cable spacer 10 was manufactured by the following method.

A vinyl ester resin (Ester H8100, manufactured by Mitsui Chemicals, Inc.) containing a peroxide catalyst is impregnated into PBO fiber (Zylon, manufactured by Toyobo Co., Ltd.), which is drawn and molded to obtain a PBO fiber content. Is about 60% outer diameter6.
As a 15 mm uncured linear product, the product is led to the head of a melt extruder, and the outer periphery thereof is extruded from a die with an LLDPE resin (NUCG5350 manufactured by Nippon Unicar Co., Ltd.), and is coated in an annular shape. The outer diameter is 8mm,
An uncured linear material having a 925 mm primary coating layer 14 was obtained and introduced into a 10 m long heat curing tank filled with high-pressure steam at 120 ° C. for curing.

Next, the tensile strength member 15 having the PFRP 12 and the primary coating layer 14 is led to the head of the melt extruder, and is melted into LLDPE (manufactured by Nippon Unicar Co., Ltd.).
NUCG5350) to form a first pre-coating layer 16 having a thickness of 1.5 mm and an outer diameter of 11 mm.

Subsequently, the second and third preliminary coatings were applied in two steps so that the coating thickness was 1.25 mm and the outer diameter was 13.5 mm and 16 mm.

The pre-coated tensile strength wire having a final outer diameter of 16 mm is guided to a melt extruder for coating a spacer body to which a rotating die having an opening corresponding to the cross-sectional shape of the spacer is attached, and the HDPE resin (Nippon Polyolefin (Japan Polyolefin) KK
Z51C) and extrude it while rotating, so that the outer diameter of the rib portion is 2
4.3 mm, groove width 2.8 mm on outer circumference, groove depth 4.1 mm
Thus, a 1000-fiber induction-free (IF) type spacer 10 having 13 grooves 22 and a spacer main body coating layer 20 having a helical pitch of 500 mm was obtained.

When the tensile performance of the spacer 10 was measured, the stress at 0.2% elongation was 450 kg.

On the other hand, in the PFRP tensile strength members 12 and 15, the stress value at 0.2% elongation calculated from the tensile modulus of the PBO fiber is 686 kg. Performance retention is 65.6
%Met.

When the apparent tensile modulus was calculated from the stress at the time of 0.2% elongation, it was 8300 kg / mm ² .

Embodiment 2 FIG . PB under the same conditions as in Example 1
An uncured filament having an outer diameter of 5.75 mm with an O fiber content of 67% by volume, and an LLD having a thickness of 1.125 mm
The primary coating layer 14 made of PE is applied to make the outer diameter 8 mm, the vinyl ester resin inside is cured, and the first, second and third preliminary coating layers 16, 17 and 18 are sequentially formed in the same manner as in Example 1, Finally, the spacer main body coating layer 20 is applied and 1000
A heart IF spacer was obtained.

The stress at 0.2% elongation of the obtained IF spacer was 510 kg, and the performance retention was 76% as compared with the stress value at 0.2% elongation of 664 kg calculated from the tensile modulus of the PBO fiber. 0.8%.

The apparent tensile modulus of elasticity calculated from the stress at the time of 0.2% elongation was 10500 kg / mm ² .

Embodiment 3 FIG . PB under the same conditions as in Example 1
An uncured filament having an outer diameter of 5.75 mm with an O fiber content of 68% by volume, and an LLD having a thickness of 1.125 mm
A PE coating was applied to make the outer diameter 8 mm.
Pre-coating was performed in the same manner as described above, and then a spacer body coating was performed to obtain a 1000-fiber IF spacer.

The stress at the time of 0.2% elongation of the obtained IF spacer was 530 kg, and the performance retention was 78% as compared with the stress value at 0.2% elongation of 675 kg calculated from the tensile modulus of the PBO fiber. 0.5%.

When the apparent tensile modulus was calculated from the stress at the time of 0.2% elongation, it was 10700 kg / mm ² .

Embodiment 4 FIG . PB under the same conditions as in Example 1
An uncured filament having an outer diameter of 5.75 mm with an O fiber content of 69% by volume, and an LLD having a thickness of 1.125 mm
The outer diameter was 8 mm by applying a PE coating, followed by pre-coating in the same manner as in Example 1 and then coating the spacer body by 100%.
A zero-core IF spacer was obtained.

The stress at the time of 0.2% elongation of the obtained IF spacer was 510 kg, and the performance retention was 74 when compared with the stress value at the time of 0.2% elongation calculated from the tensile modulus of the PBO fiber of 686 kg. 0.3%.

The apparent tensile modulus of elasticity calculated from the stress at the time of 0.2% elongation was 10200 kg / mm ² .

Embodiment 5 FIG . PB under the same conditions as in Example 1
An uncured filament having an outer diameter of 4.8 mm with an O fiber content of 60% by volume, an LLDPE coating having a thickness of 0.7 mm, and a primary coating having an outer diameter of 6.2 mm were cured and cured.
Pre-coating in the order of thickness 1.4 mm and thickness 1.5 mm, that is, 9 mm and 12 mm in outer diameter, then coating the spacer body, 30 grooves of 17 mm in outer diameter having 16 grooves on the outer circumference
A zero-core IF spacer was obtained.

The stress at the time of 0.2% elongation of the obtained IF spacer was 320 kg, and the performance retention was 66 kg as compared with the stress value at the time of 0.2% elongation calculated from the tensile modulus of the PBO fiber of 482 kg. 0.4%.

The apparent tensile modulus was calculated from the stress at 0.2% elongation and found to be 8900 kg / mm ² .

Embodiment 6 FIG . PB under the same conditions as in Example 6.
The O-fiber content was 68 vol% and the outer diameter was changed to 4.6 mm to obtain an uncured filament, which was then LL with a thickness of 0.8 mm.
DPE coating and primary coating to an outer diameter of 6.2 mm, followed by curing, pre-coating in the same manner as in Example 5, followed by spacer body coating, and a 300-core IF with an outer diameter of 17 mm having 16 grooves on the outer periphery Spacers were obtained.

The stress at the time of 0.2% elongation of the obtained IF spacer was 370 kg, and the performance retention was 76% as compared with the stress value at the time of 0.2% elongation calculated from the tensile modulus of the PBO fiber of 482 kg. 0.8%.

The apparent tensile modulus of elasticity calculated from the stress at the time of 0.2% elongation was 10300 kg / mm ² .

Comparative Example 1 In the same manner as in Example 1, the outer diameter is 8
mm LLDPE coated PFRP tensile strength body, then
LLDPE pre-coating with a coating thickness of 4 mm is applied in one step,
The outer diameter was set to 16 mm, and the outer periphery thereof was coated with the spacer main body in the same manner as in Example 1 to obtain a 1000-fiber IF spacer.

0.2 of the obtained 1000-fiber IF spacer
% Elongation stress is 210 kg, and the stress value at 0.2% elongation calculated from the tensile modulus of the PBO fiber is 686 k
g, the performance retention was only 30.6%.

The apparent tensile modulus was calculated from the stress at 0.2% elongation and found to be 3900 kg / mm ² .

Comparative Example 2 In the same manner as in Example 1, the outer diameter is 8
mm LLDPE-coated PFRP linear material was obtained, and then a 2.5 mm and 1.5 mm HDPE preliminary coating was applied in order to obtain an outer diameter of 13 mm and 16 mm. Was performed to obtain 1,000 IF spacers.

The obtained 1000-fiber IF spacer of 0.2
% Elongation stress is 300 kg, and the stress value at 0.2% elongation calculated from the tensile modulus of the PBO fiber is 686 k
g, the performance retention was 43.7%.

When the apparent tensile modulus was calculated from the stress at the time of 0.2% elongation, it was 5500 kg / mm ² .

Comparative Example 3 PB under the same conditions as in Example 6.
An uncured filament having an outer diameter of 4.8 mm with an O fiber content of 60% by volume, an LLDPE coating having a thickness of 0.7 mm, and a primary coating having an outer diameter of 6.2 mm were cured and cured.
Preliminary coating with a thickness of 2.9 mm is applied in one step and the outer diameter is 12 mm
After that, the spacer body was coated to obtain a 300-fiber IF spacer having an outer diameter of 17 mm and an outer diameter of 16 grooves.

The stress at the time of 0.2% elongation of the obtained IF spacer was 190 kg, and the performance retention was 39 kg as compared with the stress value at the time of 0.2% elongation calculated from the tensile modulus of the PBO fiber of 482 kg. 0.6%.

The apparent tensile modulus was calculated from the stress at the time of 0.2% elongation, and was found to be 5,300 kg / mm ² .

Tables 1 and 2 summarize the preliminary coating conditions, the stress at 0.2% elongation, the PBO fiber performance retention, and the tensile modulus of the obtained spacers of the above Examples and Comparative Examples.

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

When the PFRP tensile strength member having the primary coating layer disposed in the center of the optical fiber cable spacer is preliminarily coated, the thickness of the first preliminary coating layer is set to 2 mm or less, and the coating is performed in a plurality of times. Therefore, when the first preliminary coating layer is cooled and solidified from the molten state, it is possible to suppress the thermal contraction of the PFRP tensile strength member, so that the reduction rate of the tensile performance is small, and the reinforcing performance of the PBO fiber in the PFRP is effectively maintained. it can.

Further, the volume content of the PBO fiber is set to 67 to 6
By setting it to 9%, the stress at the time of elongation by 0.2% can be further increased, and the performance retention of the PBO fiber can be improved to 75% or more.

Therefore, the PF using PBO fiber as the reinforcing fiber
By using the RP strength member, it is possible to obtain an IF type optical fiber cable spacer having flexibility, light weight, high insulation, and non-induction.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an embodiment of an optical fiber cable spacer using a PFRP wire as a tensile member according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Spacer for optical fiber cables 12 PFRP 14 Primary coating layer 15 Strength member 16 First preliminary coating layer 17, 18 Second and third preliminary coating layer 20 Spacer main body coating layer 22 Groove

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Nori Ishii 2-1-1 Yabuta Nishi, Gifu City, Gifu Prefecture Ube Nitto Kasei Co., Ltd. Gifu Research Institute (72) Inventor Ken Harada 2-chome Yabuta Nishi, Gifu City, Gifu Prefecture No. 1 Ube Nitto Kasei Co., Ltd. Gifu Factory (72) Inventor Satoshi Shimomura 2-1-1 Yabuta Nishi, Gifu City, Gifu Prefecture Ube Nitto Kasei Co., Ltd. Gifu Factory (72) Inventor Hideyuki Iwata Nishi Shinjuku-ku, Tokyo Shinjuku 3-chome 19-2 Nippon Telegraph and Telephone Corporation F-term (reference) 2H001 BB09 DD11 KK08 KK12 MM01 PP01

Claims (5)

[Claims] 1. A spacer for an optical fiber cable in which a tensile member is arranged at the center and a spiral groove is formed on the outer periphery with a thermoplastic resin, wherein the tensile member is a polyparaphenylene benzobisoxazole (PBO) fiber. A cured non-cured thermosetting resin in a state in which a primary coating layer in which the outer periphery of an uncured FRP impregnated with a cured thermosetting resin is coated with a thermoplastic resin is formed, 0.2 An apparent fiber elastic modulus, which can be calculated from the% elongation stress value, is 8000 kg / mm ² or more. 2. An outer periphery of a primary coating layer of the tensile strength member,
2. The optical fiber cable spacer according to claim 1, wherein the preliminary coating layer is applied in a plurality of times, and the first coating thickness is 2 mm or less. 3. The PBO fiber volume content of the FRP is:
The optical fiber cable spacer according to claim 1, wherein the content is 67 to 69%. 4. An apparent tensile modulus of elasticity which can be calculated from a stress value at 0.2% elongation of said tensile strength member is 10,000 kg / m.
optical fiber spacer cable of claim 2-3, wherein a is m ² or more. 5. A predetermined number of PBO fibers are impregnated with a thermosetting resin, drawn into an uncured filament, guided to the head of a melt extruder, and the outer periphery is melted. The primary coating is cyclically coated with a thermoplastic resin, which is immediately cooled, and then the internal thermosetting resin is heated and cured in a heating and curing bath. The outer periphery of the primary coating layer is heated to a thickness of 2 mm or less. A method for manufacturing an optical fiber cable, comprising: preliminarily coating a resin having compatibility with a thermoplastic resin, and then coating a spacer main body with a thermoplastic resin.