JP3502273B2 - Fiber optic cable spacer - Google Patents

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 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 near the high voltage power line in order to ensure work safety.
In order not to be affected by the magnetic field, the cable member is required to be non-metallic (non-metallic).

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

Since the tensile strength of such a non-metallic cable is required to have high tensile properties,
FRP (hereinafter sometimes referred to as PFRP) using polyparaphenylene benzobisoxazole (hereinafter referred to as PBO) fiber having a tensile elastic modulus of 00 kg / mm ² or more as a reinforcing fiber is suitable.

[0004]

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

The cause of this is that the heat generated by the cooling and solidification of the melt-extruded coating portion is applied when preliminarily coating to secure the groove shape on the outer periphery of the strength member or when coating the spacer body to form the groove. It is conceivable that due to the contraction, a compressive force acts along the longitudinal direction of the strength member, and the PFRP receives compressive stress.

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

Therefore, the present invention has been completed by intensive research for the purpose of providing a spacer for an optical fiber cable which uses a PFRP wire as a tensile strength member and has excellent tensile performance.

[0008]

To achieve the above object, according to an aspect of the present invention provides an optical fiber spacer cable obtained by forming a spiral groove in the outer periphery to place the tension member in the middle of a thermoplastic resin, the tensile strength The body is polyparaphenylene
Benzobisoxazole (PBO) fiber, and (PB
O) An uncured state obtained by impregnating a fiber with an uncured thermosetting resin
The primary coating layer of the thermoplastic resin that coats the outer periphery of the FRP
And having the thermosetting resin hardened after the formation of the primary coating layer.
It is the one that has been converted into
When the apparent tensile elastic modulus is 8000 kg / mm ² or more
Yes, the outer periphery of the primary coating layer is divided into multiple times
First coating of said precoat layer
It is characterized in that the thickness is 2 mm or less. Also,
The spacer for an optical fiber cable of the present invention is the above-mentioned PFR.
The PBO fiber volume content of P can be set within the range of 67 to 69%. Further, as an even more preferable physical property range of the tensile strength member, the apparent tensile elastic modulus which can be calculated from the stress value at 0.2% elongation is 10,000 kg / mm.
It should be ² or more .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the present invention, polyparaphenylene benzobisoxazole (PBO) fiber having a high tensile elastic modulus is used as the reinforcing fiber of the FRP tensile strength wire.

By using PBO fibers, PBO
This is because the fiber has a high tensile elastic modulus, so that the required fiber cross-sectional area is small, and as a result, the diameter and weight of the FRP can be reduced.

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

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

The PBO reinforcing fiber is impregnated 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.

The thermoplastic resin of the primary coating layer is selected to be compatible with the thermoplastic resin of the preliminary coating layer which is applied to secure the accuracy of the shape of the spiral groove prior to the subsequent coating of the spacer body. The coating thickness is about 0.5
~ 1.5 mm.

If the coating thickness is less than 0.5 mm, there is a risk that the uncured resin inside will leak out due to pinholes, etc.
If it exceeds 1.5 mm, there is a problem that the physical properties of FRP are deteriorated by the partial curing due to heat during the formation of the primary coating layer.

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

When the outer diameter of the groove bottom of the spacer main body is about 1.3 times the outer diameter of the primary coating layer and the groove of the spacer main body is a shallow groove, preliminary coating is not always necessary, and direct coating is not necessary. A spacer body coating may be applied.

The primary coating layer is made of low density polyethylene (L
DPE) and the like are preferable because they are easily anchor-bonded at the interface of PFRP, and the pre-coating layer and the spacer main body coating layer have excellent low-temperature physical properties, and therefore polyethylene resin such as high-density polyethylene (hereinafter referred to as HDPE). Is generally recommended.

Further, a PF having a primary coating layer after curing
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.

The reason for this is that when cooling the preliminary coating layer,
Causes a heat shrinkage force due to cooling and solidification of the preliminary coating layer.
It This heat shrinkage force is generated in the PFRP inside the precoat layer.
The thickness of the preliminary coating layer exceeds 2 mm at this time
Then, the heat shrinkage force increases and the tensile elastic modulus of PFRP increases.
Since it lowers, it is necessary to make it 2 mm or less.

The reason why the apparent tensile elastic 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 for the optical cable.

That is, in order to effectively protect and carry the optical fiber when tension acts on the optical cable,
It is necessary to develop a predetermined stress when stretched by 2%, and from this point, a tensile modulus of elasticity of 8000 kg / mm ² or more is required.

The apparent tensile elastic modulus at 0.2% extension is a constant-speed extension type tensile tester (Shinko (Co., Ltd.), which holds a load cell with a load of 2000 kg, gripping 100 mm at both ends of a 800 mm long sample. ): TOM) 5m
A tensile test was performed at m / min, and the load-elongation curve was calculated from the gradient of a straight line connecting the 0 point and the 10.2% elongation stress measurement point.

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 PBO fiber volume content is within this range, it is preferable because the tensile elastic modulus is further improved.

Also, using polyparaphenylene benzobisoxazole (PBO) fiber as a reinforcing fiber, the apparent tensile modulus which can be calculated from the stress value at 0.2% elongation is 1000.
It is preferably 0 kg / mm ² in terms of further improving the tensile performance.

Spacer for optical fiber cable having the above configuration
In the case of manufacturing, a predetermined number of PBO fibers are impregnated with a thermosetting resin, and this is drawn to form an uncured linear filament, which is then guided to the head section of the melt extruder to The molten thermoplastic resin is firstly coated in an annular shape, which is immediately cooled, and then the thermosetting resin inside is heat-cured in a heat-curing tank.

In order to prevent hardening, the formation of this primary coating layer introduces uncured FRP to the guide jacket attached to the head of the melt extruder through cooling water, and to the outer periphery of the guide jacket of the melt extruder head. The molten thermoplastic resin is extruded in a drawn state from an annular die having a discharge opening larger than the outer diameter of the uncured FRP to be coated, and the inner diameter of the coating cone is brought into contact with the uncured FRP to form a cooling water tank. By guiding and cooling the primary coating layer, the surface or the like of the uncured resin inside does not start to partially cure.

Subsequently, uncured P having this primary coating layer
The FRP is passed through a heating and curing tank to cure the resin inside, but the temperature is changed by using high-pressure steam as a heat medium for curing.
FR near the softening point of the thermoplastic resin of the primary coating layer
Since the outer circumference of the FRP and the inner circumference of the primary coating layer undergo fluid contact under pressure in combination with the heat of curing of P, the PFRP and the primary coating layer can be in an anchor-bonded state after curing. The performance of the resulting spacer as a strength member is secured.

The preliminary coating layer is applied to the outer periphery of the primary coating layer after curing the PFRP. The coating thickness of the preliminary coating layer in the first stage is 2 mm or less for the above reason, and the thermoplasticity of the primary coating layer is set to 2 mm or less. Precoat with a resin that is compatible with the resin.

Preliminary coating depends on the groove depth of the spacer to be obtained.
As described in No. 81763, in order to adjust 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 adjusting the outer diameter of the preliminary coating layer accordingly,
A thermoplastic resin having compatibility with the preliminary coating layer is coated on the spacer body having grooves of predetermined dimensions on the outer circumference.

In the present invention, the term "annular coating" means that the coating is seamless and closed. less than,
The present invention will be described by way of preferred embodiments.

Example 1. FIG. 1 shows a cross-sectional shape of the optical fiber cable spacer according to the present embodiment.

The spacer 10 shown in FIG. 1 includes a PFRP wire 12 having PBO fibers as reinforcing fibers, a tensile strength member 15 composed of a primary coating layer 14 made 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 provided on the outer circumferences of the first, second and third preliminary coating layers 16, 17, 18 and the third preliminary coating layer 18, which have been applied in three stages in order to store the optical fiber in a predetermined shape. To form a groove 22 for. 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 PBO fiber (Zyron manufactured by Toyobo Co., Ltd.) was impregnated with a vinyl ester resin (Ester H8100 manufactured by Mitsui Chemicals Co., Ltd.) containing a peroxide catalyst, and was drawn to form a PBO fiber. Outer diameter of about 60% 6.
As an uncured linear material of 15 mm, it was introduced into the head of a melt extruder, and LLDPE resin (NUCG5350 manufactured by Nippon Unicar Co., Ltd.) was extruded from the die onto the outer periphery thereof to form an annular coating, which was immediately cooled. With an outer diameter of 8 mm,
An uncured linear material having a primary coating layer 14 of 925 mm was obtained, which was introduced into a heating curing tank filled with high-pressure steam at 120 ° C. and having a length of 10 m to be cured.

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

Subsequently, the coating thickness was set to 1.25 mm, and the second and third preliminary coatings were performed in two steps so that the outer diameters were 13.5 mm and 16 mm.

This pre-coated tensile strength wire having a final outer diameter of 16 mm is led to a melt extruder for coating a spacer main body to which a rotary die having an opening corresponding to the cross-sectional shape of the spacer is attached, and HDPE resin (Japan Polyolefin ( KK
Z51C) is rotated and extruded, and the outer diameter of the rib is 2
4.3mm, groove width 2.8mm on the outer circumference, groove depth 4.1mm
The 1000 core type induction-free (IF) type spacer 10 having the spacer body coating layer 20 having 13 grooves 22 and having a spiral pitch of 500 mm was obtained.

When the tensile performance of this 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, so that the IF spacers obtained by comparing the stress values are Performance retention rate is 65.6
%Met.

Further, the apparent tensile modulus of elasticity was calculated from the stress at 0.2% elongation to be 8300 kg / mm ² .

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

The stress of the obtained IF spacer at the time of 0.2% extension is 510 kg, and the performance retention rate is 76 when compared with the stress value at the time of 0.2% extension 664 kg calculated from the tensile elastic modulus of PBO fiber. It was 0.8%.

The apparent tensile elastic modulus was calculated from the stress at 0.2% elongation to be 10500 kg / mm ² .

Example 3. PB under the same conditions as in Example 1
O-fiber content is 68% by volume to make an uncured filament having an outer diameter of 5.75 mm, and an LLD having a thickness of 1.125 mm.
PE coating was applied to obtain an outer diameter of 8 mm, and the following Examples 1 and 2 were used.
A 1000 core IF spacer was obtained by pre-coating in the same manner as above and then coating the spacer body.

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

The apparent tensile modulus of elasticity was calculated from the stress at 0.2% elongation to be 10700 kg / mm ² .

Example 4. PB under the same conditions as in Example 1
O-fiber content is 69% by volume to make an uncured filament with an outer diameter of 5.75 mm, and an LLD having a thickness of 1.125 mm.
PE coating was applied to give an outer diameter of 8 mm, and precoating was carried out in the same manner as in Example 1 below.
A 0-core IF spacer was obtained.

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

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

Example 5. PB under the same conditions as in Example 1
After the O fiber content is 60% by volume to make an uncured filament having an outer diameter of 4.8 mm, a LLDPE coating having a thickness of 0.7 mm is applied to the filamentous material, and the outer diameter of 6.2 mm is primarily coated and cured.
The thickness of 1.4 mm and the thickness of 1.5 mm are preliminarily coated in this order, that is, the outer diameters are 9 mm and 12 mm, and then the spacer main body is coated, and the outer diameter is 17 mm with 16 grooves.
A 0-core IF spacer was obtained.

The stress of the obtained IF spacer at the time of 0.2% extension is 320 kg, and the performance retention rate is 66 when compared with the stress value at the time of 0.2% extension 482 kg calculated from the tensile elastic modulus of PBO fiber. It was 0.4%.

Further, the apparent tensile modulus of elasticity was calculated from the stress at 0.2% elongation to be 8900 kg / mm ² .

Example 6. PB under the same conditions as in Example 6
The O fiber content was changed to 68% by volume and the outer diameter was changed to 4.6 mm to obtain an uncured filamentous product, and LL having a thickness of 0.8 mm
After DPE coating and primary coating to an outer diameter of 6.2 mm and curing, preliminary coating is performed in the same manner as in Example 5, and then spacer body coating is performed to form a 300-core IF having an outer diameter of 17 mm and 16 grooves on the outer circumference. The spacer was obtained.

The stress of the obtained IF spacer at the time of 0.2% extension is 370 kg, and the performance retention rate is 76 when compared with the stress value at the time of 0.2% extension 482 kg calculated from the tensile elastic modulus of PBO fiber. It was 0.8%.

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

Comparative Example 1. The outer diameter is 8 in the same manner as in Example 1.
mm LLDPE coated PFRP strength member, then
Apply LLDPE preliminary coating with a coating thickness of 4 mm in one step,
The outer diameter was set to 16 mm, and the outer circumference thereof was coated with a spacer body in the same manner as in Example 1 to obtain an IF spacer having 1000 cores.

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

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

Comparative Example 2. The outer diameter is 8 in the same manner as in Example 1.
mm LLDPE-coated PFRP linear material is obtained, and then 2.5 mm and 1.5 mm HDPE preliminary coating are sequentially applied to obtain outer diameters of 13 mm and 16 mm, and the outer circumference thereof is coated with the spacer body as in Example 1. Then, a 1000-fiber IF spacer was obtained.

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

The apparent tensile elastic modulus was calculated from the stress at 0.2% elongation to be 5500 kg / mm ² .

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

The stress of the obtained IF spacer at the time of 0.2% extension is 190 kg, and the performance retention rate is 39 when compared with the stress value at the time of 0.2% extension 482 kg calculated from the tensile elastic modulus of PBO fiber. It was 0.6%.

The apparent tensile modulus of elasticity was calculated from the stress at 0.2% elongation to be 5300 kg / mm ² .

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

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

EFFECTS OF THE INVENTION When pre-coating a PFRP tensile strength member having a primary coating layer arranged in the center of a spacer for an optical fiber cable, 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. Thus, when the first preliminary coating layer is cooled and solidified from the molten state, it is possible to suppress the heat shrinkage of the PFRP tensile strength member, so that the reduction rate of the tensile performance is small and the reinforcement performance of the PBO fiber in the PFRP is effectively maintained. it can.

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

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

[Brief description of drawings]

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

[Explanation of symbols]

10 Optical fiber cable spacer 12 PFRP 14 Primary coating layer 15 Strength member 16 First preliminary coating layer 17, 18 Second and third preliminary coating layers 20 Spacer body coating layer 22 groove

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Harada 2-1-1 Yabuda Nishi, Gifu City Gifu Prefecture Ube Nitto Kasei Co., Ltd. Gifu Factory (72) Inventor Tomofumi Shimomura 2-chome Yabuta Nishi, Gifu City Gifu Prefecture No. 1-1 Ube Nitto Kasei Co., Ltd. Gifu factory (72) Inventor Hideyuki Iwata 3-19-2 Nishishinjuku 3-chome, Shinjuku-ku, Tokyo Nihon Telegraph and Telephone Corporation (56) Reference JP-A-4-284409 (JP, A) JP 8-21935 (JP, A) JP 8-146263 (JP, A) JP 10-170778 (JP, A) JP 59-101333 (JP, A) Actual Kai 63-188614 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/44

Claims (3)

(57) [Claims] 1. A spacer for an optical fiber cable in which a tensile strength member is arranged in the center and a spiral groove is formed on the outer circumference by a thermoplastic resin, wherein the tensile strength member is polyparaphenylene benzobisoxa
Zol (PBO) fiber and the above (PBO) fiber are uncured
The outer circumference of the uncured FRP impregnated with the chemical thermosetting resin
And a primary coating layer of a thermoplastic resin for covering, and curing the thermosetting resin after the formation of the primary coating layer.
The apparent tensile elasticity that can be calculated from the stress value at 0.2% elongation
The rate is 8000 kg / mm ² or more, and the outer circumference of the primary coating layer is preliminarily applied in multiple times.
A preliminary coating layer, and the coating thickness of the first coating layer is
A spacer for an optical fiber cable, which is 2 mm or less . 2. The PBO fiber volume content of the FRP is
67-69% is the light according to claim 1, characterized in that
Fiber cable spacer. 3. A stress value at 0.2% elongation of the tensile strength member.
The apparent tensile modulus that can be calculated from
It is mm ² or more, 2 or 3 notes.
Spacer for mounted optical fiber cable.