JPS61179407A - Spacer for carrying optical fiber and its production - Google Patents

Abstract

PURPOSE:To improve the performance of a spacer by a simple process for production by fusing and adhering a spacer body and primary coating layer and forming continuously plural grooves for mounting optical fibers extending continuously in the longitudinal direction to the spacer body. CONSTITUTION:Tensile wires 1 having twisted structure are passed into a cross head die and a hard and heat-resistant thermoplastic resin is melt-extruded to the outside periphery thereof to form the primary coating layer having at least >=0.25mm coating layer. The spacer body 9 formed with the plural grooves for carrying the optical fibers extending in the longitudinal direction is coated on the outside periphery of the primary coating layer by using the soft thermoplastic resin having large compatibility with the termoplastic resin by which the spacer 12 is obtd. The thermoplastic resin for primary coating is preferably selected from the resins which have the stable heat resistance with a temp. change and hardness in the stage of using the resins as the element for an optical fiber cable and have >=150kg/mm<2> bending modulus and >=100 deg.C thermal deformation temp. under 18.6kg/cm<2> load.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is used as an element of an optical fiber cable,
The present invention relates to a spacer for collectively protecting and supporting a plurality of optical fibers, and a method for manufacturing the spacer.

(Prior art and its problems) This type of spacer uses a monotonic wire, twisted steel wire, or the like as a tensile strength wire, and forms a spacer body around the outer periphery of a thermoplastic resin. A type with a spiral groove is known, and its manufacturing method involves inserting a tensile strength wire crosswise into a Rad die, and melting and extruding the thermoplastic resin from the die while rotating a die with various mouth shapes. Methods of coating and cooling and solidifying are known.

In such a conventional manufacturing method, for example, a twisted steel wire is used as the tensile strength wire, high-density polyethylene is used as the resin for forming the spacer body, and the spacer is manufactured by extrusion coating.

Therefore, in the spacer having this configuration, the bonding force in the longitudinal direction between the tensile strength wire and the spacer body is obtained by the unevenness based on the twisted structure of the twisted steel wire and the extrusion-coated thermoplastic resin entering the unevenness. It relied exclusively on the locking force of so-called anchor adhesion.

However, in such anchor bonding, the bonding force between the tensile strength wire and the spacer body is insufficient, and therefore there are problems as shown below.

In other words, especially when a soft resin such as polyethylene or polypropylene homopolymer is used for the spacer body,
When the tensile strength wire and the spacer body are insufficiently bonded or bonded, and the optical fiber is installed and laid in the groove of the spacer, the thermoplastic resin of the spacer body expands and contracts due to temperature changes, causing microscopic damage to the optical fiber. There was a concern that this would cause bending loss and increase transmission loss.

This phenomenon is caused by the fact that the above-mentioned thermoplastic resin has a larger coefficient of linear expansion than the tensile strength line, and the thermal stress that expands and contracts in the longitudinal direction in response to changes in the environmental temperature of the spacer body causes the anchor bond between the tensile strength line and the spacer body. This is thought to be due to the fact that the locking force is larger than the locking force of the spacer body, and that the thermoplastic resin is thermally shrunk due to the influence of residual strain when the spacer body is cooled and solidified when the spacer body is molded.

In particular, it is thought that the locking force in the above-mentioned anchor adhesion decreases because the thermoplastic resin part becomes soft at high temperatures and becomes easily deformed over the unevenness caused by the twisted structure of the tensile strength wire.

Here, in order to solve this problem and increase the locking force in anchor bonding, it is possible to use a hard or heat-resistant thermoplastic resin as the forming resin for the spacer body, but with this configuration, the tensile strength Although the bonding strength between the wire and the spacer body is improved, it lacks flexibility as a spacer for supporting optical fiber cables, which causes handling problems when installing optical fibers into the spacer grooves and during installation work. do.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to minimize dimensional changes due to changes in environmental temperature, and to reduce adverse effects such as increased transmission loss of optical fibers. A spacer for supporting an optical fiber and its I
It is here to encourage the W method.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a spacer for supporting an optical fiber that includes tensile strength wires having a twisted structure and a hard and heat-resistant thermoplastic resin surrounding the tensile strength wires. and a spacer body formed around the outer periphery of the primary coating layer from a thermoplastic resin that has a high compatibility with the thermoplastic resin and is softer than the thermoplastic resin, the spacer The main body and the primary coating layer are fused and bonded, and the spacer main body is formed with a plurality of grooves for attaching optical fibers continuously extending in the longitudinal direction. As a manufacturing method for a fiber-supporting spacer, a tensile strength wire having a twisted structure is inserted through a RAD die crosswise, and a hard and heat-resistant thermoplastic resin is melt-extruded around the outer circumference of the wire in a ring shape to a thickness of at least 0.25 mm.
After forming the primary coating layer having the above coating thickness, a plurality of grooves extending in the longitudinal direction are formed on the outer periphery of the primary coating layer using a soft thermoplastic resin that has a high compatibility with the thermoplastic resin. It is characterized by being coated in such a manner that it is formed.

To explain in more detail, twisted steel wires, twisted wires of II fiber reinforced plastic, etc. are used as the above-mentioned tensile strength wires, and by twisting a plurality of wires together, an uneven twisted structure is formed on the surface, and a predetermined twisting structure is formed. It is sufficient if the tension is as follows.

In addition, the thermoplastic resin for the primary coating has heat resistance and hardness that are stable against environmental temperature changes when used as an element of an optical fiber cable, and has a bending resistance of 150 kg/m or more. Elastic modulus and 18.6/
It is desirable to select a resin whose heat deformation temperature under C-load is IOO'C or higher.

Resins that satisfy these conditions include thermoplastic resins reinforced with reinforcing fibers such as glass fibers and carbon fibers,
Examples include glass fiber-reinforced polyethylene, polypropylene, nylon, carbon fiber-reinforced resins, ABS resins, and various fiber-reinforced modified resins.

If a resin with a bending modulus of elasticity and a thermal deformation temperature lower than the above values is used in a furnace as a supporting element for an optical fiber cable, it will not twist due to changes such as expansion or thermal contraction due to environmental temperature changes during use. The locking horns between the uneven parts of the structure and the primary coating resin layer may become insufficient, and the spacer body welded to the primary coating resin layer may shrink due to heat, which may adversely affect the optical fiber installed in the groove of the spacer body. There is a risk that it may cause harm.

In addition, the thickness of the primary coating layer made of the above-mentioned resin should be approximately Q5nv larger than the apparent outer diameter of the tensile strength wire of the twisted structure, that is, the thickness at the thinnest part should be 0.2nv.
It is desirable that the thickness be 5 ml or more from the viewpoint of welding and joining with the spacer main body that will be formed later.

On the other hand, the resin for forming the spacer body may be any resin that has high compatibility with the primary coating layer and is capable of a-bonding with the primary coating layer, but the resin has the functions required for the main body of the sub-IJ'. requires sufficient physical properties to partition each optical fiber strand or core, and strength against radial lateral pressure.From these points of view, high-density polyethylene, low-density polyethylene, polypropylene, ABS, nylon 1
Examples include small mopolymers such as No. 2, and various modified resins or copolymers thereof.

When JQ flexibility is particularly required, a soft resin may be selected and used.

The shape of the spacer body is determined by the requirements of the optical fiber 82, such as full number, groove depth, groove width, outer diameter J5 of the main body, parallel groove, spiral groove, etc.

(Operations and Effects of the Invention) In the optical fiber supporting spacer of the present invention having the above-described structure, the uneven portions of the tensile strength wires having a twisted structure are coated with a primary coating layer 3 made of a hard and heat-resistant thermoplastic PfI resin. The locking force due to the anchor adhesion between the two is stable over a wide range of changes in environmental humidity, and is particularly prevented from decreasing at high temperatures.

In addition, since the spacer main body to which the optical fiber is attached is made of a thermoplastic resin that is softer than the resin of the primary coating layer, the flexibility required for M installation is ensured. Moreover, since these resins have high compatibility with phase n, the bonding strength between the primary coating layer and the spacer body can also be maintained high.

Furthermore, according to the manufacturing method of the present invention, a spacer having the above-mentioned effects can be manufactured relatively easily, and since the outer periphery of the tensile strength wire is coated with thermoplastic resin in two stages, Residual distortion can be reduced.

(Example) Examples and comparative examples of the present invention will be described in detail below with reference to the accompanying drawings.

(Example 1) A 9-wood steel wire with a diameter of 0.38 mm was used as the tensile strength wire 1 (
3+6) Twisted steel wires with an apparent outer diameter of 1.2 mm (the envelope diameter connecting the outer periphery of each strand, both r' are the same) were used, and the surface was cleaned with acetone and degreased. After that, the cloth is passed through the RAD die 2, a primary coating layer 3 is applied with glass carbon fiber reinforced polyethylene with a glass content of 15%, and after being introduced into the cold JJI solidification tank 4, it is wound up on a drum 5 and the outer diameter of the coating is 2. A core strand 7 of .2 mm was obtained.

This strand 7 is further passed through a rad die into a cross having a die corresponding to the cross-sectional shape of the spacer, which will be described later.
While rotating, the outer periphery of the core strand 7 was made of high-density polyethylene (MI=0.3) with 98 grooves of 5.1 mm at equal intervals and a valley diameter of 2.4 mm (7) 4 threads 0'). After coating the spacer body 9 to form a spacer body 9 with a spiral pitch of 120 mm, the drum 1 is introduced into a cold W tank 10 filled with a refrigerant such as air or cooling water to be cooled and solidified.
I wound it up to 1.

The spacer 12 manufactured in this manner had the cross-sectional shape shown in FIG. 3, and the bonding strength between the spacer body and the tensile strength wire 1 made of twisted steel wire was measured by the following method.

That is, for a length of 10 mm at the end of the helical spacer body 9, the thermoplastic resin part in the cross-sectional direction of the helical spacer body 9 was brought into contact with a jig of the chuck part of a tensile tester,
A tensile test was carried out at a tensile rate of 5 mm/min to measure the tensile shear bonding strength, and the value was divided by the area of the apparent outer periphery of the tensile strength line 1 to obtain the bonding strength (withdrawal strength). The bonding strength of the spacer of this example measured by this measurement method was 42 kg/crl.

In addition, a sample with a length of approximately 1 m was placed in a dry hot air oven at 60°C and 100°C, and left for 1 hour, and then left at 23°C (room temperature) for 30 minutes, and then the length of the main body 9 was measured. Measure (L
) 111111, and the heat shrinkage rate was measured using the following formula.

Heat shrinkage rate = ((1000-L) / 1000)
x 100 (%) In the sample of this example, the heat shrinkage rates at 60°C and 100°C were respectively 0%.

Furthermore, at -35°C for 1 hour, and then at 80°C for 1 hour.
When the heat cycle was repeated 30 times and the shrinkage rate was measured in the same way, the shrinkage rate was 0.
A value of 15% was obtained.

Furthermore, the spacer body 9 has the tensile strength line 1 arranged in the center.
The flexibility of was measured by the following means.

The sample for measurement was semicircular with a diameter of 100 mm, and the repulsive force due to the semicircular sample was measured using a spring balance. The value of the sample of this example by this measurement method is 0.1
It was 5-.

In addition, all physical property values such as bonding strength in the following examples and comparative examples are values measured using the method described above.
The explanation of the measurement method will be omitted hereafter.

(Comparative Example 1) As the tensile strength wire 1, the same one as in Example 1 was used,
The secondary coating layer 3 was not formed, but after degreasing, it was inserted into the same cloth as in Example 1 through the RAD die 8, and a spacer body 9 of the same form was made of high-density polyethylene (MI=0.3). Formed.

That is, in Comparative Example 1, the spacer 12 was formed by omitting the step shown in FIG. 1 described in Example 1 above.

As a result, the joint strength was 13 kg/cd, and the heat shrinkage rate at 60℃ and 100℃ was 0.1~0゜15%, respectively.
, 0.3 to 0.55%, the thermal shrinkage rate after heat cycle was 1.6%, and the flexibility was 0.15 kg, and all other properties except flexibility were inferior to Example 1. Ta.

(Comparative Example 2) The configuration of the tensile strength line 1, the dimensions and shape of the spacer body 9, etc.
Under the same conditions as in Example 1 and Comparative Example 1 above, the resin for forming the spacer body 9 was the same glass fiber reinforced polyethylene as that used for the primary coating in Example 1, and the spacer 12 was formed in the same manner as in Comparative Example 1. When we measured each characteristic, we obtained the following results.

That is, the bonding strength was 44 kg/cm, the heat shrinkage rates at 60°C and 100°C were 0%, and the heat shrinkage rate after heat cycle was 0.1%, and these values were compared with Example 1 above. However, the flexibility is comparable to that of 0.
The weight is 35 kg, which poses a problem when creating and installing optical fiber cables as a spacer of this standard.

(Example 2) A steel wire with a diameter Q of 6+nm was used as the tensile strength wire 1 (1+6)
Using twisted steel wire with an apparent outer diameter of 1.81 twisted in the structure of a book, after cleaning the surface with acetone and degreasing it, insert it into the cross through RADODAI 2, and heat-resistant ABS (Denki Kagaku Kogyo) A primary coating layer 3 was formed using a coating (trade name: H8800), introduced into a cooling and solidifying tank 4, and then wound around a drum 5 to obtain a core strand 7 having a coating outer diameter of 3°Qmm.

This element 17 is further inserted into a cross having a die corresponding to the cross-sectional shape of a spacer, which will be described later, through a rad die, and while rotating this die 8, a modified ABS (
Made by Ube Saikon (trade name: UKB440), the diameter of the mountain is 13. After coating to form a spacer body 9 having 6 protrusions with a root diameter of 5.8+nm and a spiral pitch of 150 mff1, a cooling tank 10 is filled with a coolant such as air or cooling water. The mixture was introduced into a container, cooled and solidified, and then wound up on a drum 11.

The bonding strength of the obtained spacer 12 is 85 kg/c
A large value of +/ was obtained, the heat shrinkage rates at 60°C and 100°C and the heat shrinkage rate after heat cycle were each 0%, and the flexibility was 1.4kg.

(Comparative Example 3) As the tensile strength line 1, the same one as in Example 2 was used,
The primary coating layer 3 was not formed, and after degreasing, it was inserted through the Rad die 8 into the same cloth as in Example 2, and a spacer body 9 having the same form as in Example 2 was formed using the same modified ABS. That is, in Comparative Example 3, the spacer 12 was formed by omitting the step shown in FIG. 1 described in Example 2 above.

As a result, the bonding strength was 15 kg/cm, 60℃ and 1
The heat shrinkage rates at 00°C are -0 and 15%, respectively.

-0.25%, heat shrinkage rate after heat cycle is 1°3%
The flexibility was 1.2 kg, and all other properties except the flexibility were inferior to those of Example 2, particularly the bonding strength was 115 or less.

(Comparative Example 4) The configuration of the tensile strength line 1, the dimensions and shape of the spacer body 9, etc.
Under the same conditions as in Example 2 and Comparative Example 3 above, the resin for forming the spacer body 9 was the heat-resistant ABS used for the primary coating in Example 2, the spacer 12 was formed with the same dimensions as in Comparative Example 3, and each characteristic was evaluated. As a result of measurement, the following results were obtained.

That is, the bonding strength is 87 kg/cJ, 60°C and 1
The thermal contraction rate at 00°C is 0%, and the thermal contraction rate after heat cycle is 0%, and these values are comparable to those in Example 2 above, but the flexibility is 3.5 kg. As a result, the rigidity becomes too large, which causes problems when installing optical fiber cables.

(Example 3) A steel wire with a diameter of 0.38 mm was used as the tensile strength wire 1 (3+6)
Using twisted steel wire with an apparent outer diameter of 1.2 mm twisted in the structure of a book, after cleaning the surface with acetone and degreasing it, insert it into the cross through RADODAI 2 and insert Tismo-reinforced polypropylene (Dainichiseika A primary coating 3 was formed using the product (trade name: PPT1235), introduced into a cold fJl solidification tank 4, and then wound around a drum 5 to obtain a core strand 7 having a coating outer diameter of 2.2 mm.

This strand 7 is inserted into a cross having a die corresponding to the cross-sectional shape of the spacer, which will be roughly described later, through a rad die, and while rotating the die 8, a polypropylene-ethylene copolymer ( Manufactured by Ube Industries: Product name J701H
), the peak diameter is 5.5 mm and the valley diameter is 3.5 mm at equal intervals. Qmm
After coating the spacer body 9 to form a spacer body 9 having six protrusions with a spiral pitch of 200 mm, the spacer body 9 is introduced into a cooling tank 10 filled with a coolant such as air or cooling water, and cooled and solidified. , and then wound onto the drum 11.

The bonding strength of the obtained spacer 12 is 35 kg/c
d.

Heat shrinkage rate at 60°C and 100°C is 0%, heat shrinkage rate after heat cycle is 0.05%, flexibility is 0.2
It was kg.

(Comparative Example 5) The same tensile strength wire as in Example 3 was used, the primary coating layer 3 was not formed, and after degreasing, the wire was inserted into the same cloth as in Example 3 through the RAD die 8. A spacer body 9 having the same shape was formed from polypropylene. That is, in Comparative Example 5, the spacer 12 was formed by omitting the step shown in FIG. 1 described in Example 3 above.

As a result, the bonding strength is 14 kg/cze, the heat shrinkage rate at 60℃ and 100℃ is 0.05%, respectively, the heat shrinkage rate after heat cycle is 0.15%, and the flexibility is 0.1
The weight was 8 kg, and all other properties except flexibility were inferior to those of Example 3 above.

The table below summarizes the above examples and comparative examples.

As is clear from the binding in the table, the space for supporting an optical fiber of the present invention manufactured by the manufacturing method according to the present invention has a primary coating made of a hard thermoplastic resin on the uneven portion of the M structure of the tensile strength wire 1. Because Layer 3 is closely packed, a large bonding strength can be obtained.Secondly, because the thermal deformation temperature of this resin is high, the shrinkage rate is small over a wide range of environmental temperatures, and temperature changes are reduced. The bonding strength is also stable.

Further, since the spacer main body 9 portion is softer than the primary coating layer 3, the flexibility necessary for moving the optical fiber without inserting it into the groove of the main body 9 is ensured.

Furthermore, since the resins forming the spacer body 9 and the primary coating layer 3 have high compatibility, there is no problem with the bonding strength at their interface, and the coating process can be divided into two stages when manufacturing the spacer 12. Cold 2J] can alleviate residual strain during solidification.

(Effects of the Invention) As described above in detail in the Examples, according to the present invention, the bonding strength between the spacer body and the tensile strength wire is high, the dimensional stability against temperature changes is good, and the flexibility is moderate. It is possible to obtain a immersive effect such that an optical fiber supporting spacer equipped with an optical fiber supporting spacer can be manufactured relatively easily.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the process of primary coating of the present invention, FIG. 2 is an explanatory diagram showing the process of forming a spacer body, and FIG. 3 is a sectional view showing an example of the optical fiber supporting spacer of the present invention. . １・・・・・・・・・Tensile strength line

Claims (3)

[Claims] (1) A tensile strength wire having a twisted structure, a primary coating layer made of a hard and heat-resistant thermoplastic resin surrounding the tensile strength wire, and a material having a high compatibility with the thermoplastic resin on the outer periphery of the primary coating layer. and a spacer body formed of a thermoplastic resin softer than the thermoplastic resin, the spacer body and the primary coating layer are fused and bonded, and the spacer body has a spacer body that is continuous in the longitudinal direction. What is claimed is: 1. A spacer for supporting an optical fiber, comprising a plurality of grooves for mounting optical fibers extending along the groove. (2) The thermoplastic resin of the above primary coating layer weighs 150 kg/
It has a bending elastic modulus of mm^2 or more and is 18.6 kg/
The spacer for supporting an optical fiber according to claim 1, characterized in that the spacer has a thermal deformation temperature of 100° C. or higher under a load of cm^2. (3) A primary coating layer having a coating thickness of at least 0.25 mm is obtained by inserting a tensile strength wire having a twisted structure into a crosshead die, and melting and extruding a hard and heat-resistant thermoplastic resin around the outer circumference in a circular shape. After forming the primary coating layer, the primary coating layer is coated with a soft thermoplastic resin that has high compatibility with the thermoplastic resin so as to form a plurality of grooves extending in the longitudinal direction on the outer periphery of the primary coating layer. A method for manufacturing an optical fiber supporting spacer.