JPH1123919A - Coated optical fiber and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the coated optical fiber which has a nonpeeling coated thin layer having good adhesive strength to the clad layer of the optical fiber on the clad layer, enables a connection by a press type simple connector, and has no large variation in transmission loss owing to temperature variation and single-core cord constitution irrelevantly to the kind of the optical fiber. SOLUTION: On the clad layer 1b of the optical fiber 1, a nonpeeling primary coating 2 made of ultraviolet-ray setting resin which has good adhesive strength to the clad layer 1b and a 50 to 200 kg/mm<2> Young's modulus at room temperature, a secondary coating 3 made of ultraviolet-ray setting resin which has good peeling property to the primary coating 2 and a 0.02 to 1.0 kg/mm<2> Young' s modulus at room temperature, and a tertiary coating 4 made of ultraviolet-ray setting resin which has a 40 to 100 kg/mm<2> Young's modulus at room temperature are provided in order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber ribbon which can be connected by a crimp-type simple connector such as a caulking type connector.

[0002]

2. Description of the Related Art In recent years, a high Young's modulus (at room temperature) with good adhesion to the cladding layer
120kg / mm ² ~150kg / mm non-peelable thin layer provided consisting of about ²⁾ synthetic resin, thereon less favorable relatively Young's modulus of the release property to the thin layer (at normal temperature 5 kg / mm ² to 15kg / mm
An optical fiber cable has been developed that is provided with a protective coating layer made of synthetic resin (approximately ² ) to enable connection by a crimp-type simple connector such as a caulking connector or an elastic holding connector.

That is, in such an optical fiber core wire, only the outer protective coating layer is peeled off and connected, and the inner thin layer protects the optical fiber. The optical fiber can be connected without being damaged.

[0004]

However, in such a conventional optical fiber core, there is a drawback that, depending on the type of the optical fiber, a change in transmission loss due to a temperature change or single-core coding increases. Numerical aperture (N
A) In the case of a GI optical fiber having a core ratio of 0.28 and a core ratio of 0.8,
Single core coding was virtually impossible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been described in which a non-peelable thin layer having good adhesion to a clad layer is provided on a clad layer of an optical fiber, and a simple press-fit type is provided. An optical fiber cable that can be connected by a connector, and an optical fiber cable whose transmission loss does not greatly fluctuate due to temperature change or single-core coding for any type of optical fiber, and a method of manufacturing the same. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION An optical fiber core wire according to the present invention has a Young's modulus having good adhesion to the cladding layer of the optical fiber at room temperature of 50 kg / mm ^{2 to} 200 kg / cm.
mm ² of a synthetic resin non-releasing of the primary coating, 0.02 kg / mm good Young's modulus of the release property to the primary coating is at room temperature
^{2 ~1.0} kg / mm ² in the secondary coating of synthetic resin, has a feature that the Young's modulus is provided with a tertiary coating of 40kg / mm ² ~100kg / mm ² of synthetic resin at room temperature in this order.

The method for producing an optical fiber core wire according to the present invention is characterized in that a Young's modulus having good adhesion to the cladding layer of the optical fiber is 50 kg / mm ^{2 to} 200 kg / cm.
coating the ultraviolet curable resin mm ^2, after curing by irradiation with ultraviolet rays, thereon, the better Young's modulus of the release property to the coating at ordinary temperature 0.05kg / mm ² ~1.0kg / mm ² UV-curable resin and a Young's modulus at ordinary temperature of 40kg / mm ² ~100kg / mm
^{It is characterized in that the two} UV-curable resins are sequentially coated, and then these coatings are co-cured by irradiating UV rays.

[0008] In the optical fiber core wire of the present invention, a specific low Young's modulus low-modulus primary coating is formed on a non-peelable primary coating made of a specific high Young's modulus ultraviolet curable resin provided on the cladding layer of the optical fiber. By having a secondary coating made of UV-curable resin and a tertiary coating made of UV-curable resin with a specific high Young's modulus, the temperature change and the single-core cord can be widely used regardless of the type of optical fiber. It is possible to suppress the fluctuation of the transmission loss due to the conversion.

Further, in the method for manufacturing an optical fiber core wire according to the present invention, after coating and curing an ultraviolet curing resin for forming a primary coating, the ultraviolet curing resin for forming a secondary coating and a tertiary coating is sequentially applied. Since the coating and then co-curing, the adhesion of the primary coating to the optical fiber is increased, and the peelability of the secondary coating and the tertiary coating to the primary coating is improved, and the primary coating of the secondary coating and the tertiary coating is improved. Stripping from the coating is facilitated. Therefore, the workability and reliability at the time of connection of the optical fiber having the above characteristics by the simple crimping connector can be further improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of the optical fiber ribbon of the present invention.

In FIG. 1, reference numeral 1 denotes an optical fiber in which a cladding layer 1b is provided on a core 1a. A Young's modulus having good adhesion to the cladding layer 1b is provided on the optical fiber 1 at room temperature. Non-peelable primary coating ^{2 made of} an ultraviolet-curable resin of 50 kg / mm ^{2 to} 200 kg / mm ^2, and a good Young's modulus of 0.05 kg / mm at room temperature
^{2 ~1.0kg} / mm ² of the ultraviolet ray curable comprising a resin secondary coating 3, tertiary coating 4 having a Young's modulus consisting 40kg / mm ² ~100kg / mm ² of the ultraviolet curable resin at room temperature are provided in order.

In the present invention, the Young's modulus of the ultraviolet curable resin constituting each coating on the optical fiber 1 is limited as described above for the following reasons.

That is, the non-peelable primary coating 2 adheres well to the optical fiber 1 and functions as a protective layer for the optical fiber 1 when connecting with a simple press-fit connector. It is preferable that the UV-curable resin constituting the resin has as high a Young's modulus as possible. However, as the Young's modulus increases, the elongation at break decreases, and the resin may be damaged when the outer coating is peeled off. Therefore, in the present invention, the Young's modulus is 50 kg / mm ^{2 at} room temperature.
It is necessary to use 200 kg / mm ² of the ultraviolet ray curable resin, particularly, a Young's modulus using a 100kg / mm ² ~150kg / mm ² of the ultraviolet curable resin at room temperature is desirable.

The secondary coating 3 has an effect of suppressing an increase in transmission loss at low temperatures, and also functions as a buffer layer against lateral pressure, and has an effect of suppressing an increase in transmission loss in the case of single-core coding. Yes, the Young's modulus at room temperature is 0.02k
Even if it is less than g / mm ² or exceeds 1.0 kg / mm ² , such effects cannot be sufficiently obtained.

Further, the tertiary coating 3 has an effect of preventing the transmission loss from increasing due to the side pressure when used in combination with the secondary coating 3 while allowing the tertiary coating 3 to be handled as a core wire. Even if the rate is less than 40 kg / mm ² or exceeds 100 kg / mm ² , such effects cannot be sufficiently obtained.

In the present invention, the thickness of the non-peelable primary coating 2 is preferably 5 to 25 μm,
If it is less than 25 m, sufficient strength may not be obtained. Conversely, if it exceeds 25 μm, the outer diameter fluctuation rate exceeds the allowable range of connection by a simple connector, ± 1.5%, and the simple connector Connection becomes difficult. The more preferable thickness of the primary coating 2 depends on the diameter of the optical fiber, but is usually in the range of 5 to 10 μm.

Further, in view of the buffer effect, the thickness of the secondary coating 3 is such that the ratio r ₂ / r ₁ of the finished diameter r ₂ of the secondary coating to the finished diameter r ₁ of the primary coating is 1.4 to 2.0. It is desirable to be within the range.

As the UV-curable resin constituting each coating, there are various commercially available UV-curable resins such as urethane acrylate, epoxy acrylate and ladder type silicone resins, which satisfy the above conditions. The user can arbitrarily select what to use.

In the present invention, the secondary coating 3 includes:
For the purpose of enhancing the releasability of the primary coating 2, additives such as UV-reactive silicone and silicone may be included.

In the optical fiber cable thus configured, the secondary coating 3 and the tertiary coating 4 are easily removed at the time of connection, but the primary coating 3 is firmly adhered to the optical fiber 1 and peeled off. Instead, since the optical fiber 1 is protected, a highly reliable connection can be made by a simple crimp-type connector.

In addition, on the primary coating 3, a secondary coating 3 having a low Young's modulus excellent in buffer effect while suppressing an increase in transmission loss at a low temperature, and a tertiary coating 4 having a high Young's modulus for suppressing lateral pressure. Are provided in order, so that a decrease in transmission characteristics due to a temperature change or a side pressure is prevented.

Therefore, regardless of the type of optical fiber,
It can be widely used as a core wire that can be connected by a crimp-type simple connector.

The optical fiber core is coated with an ultraviolet curing resin for the primary coating 2 while drawing the optical fiber, is cured by irradiating ultraviolet rays, and then cured by ultraviolet irradiation for the secondary coating 2. It is preferable that the mold resin and the UV-curable resin for tertiary coating 2 are sequentially coated, and then irradiated with ultraviolet rays to be co-cured to produce the resin.

By using such a method, it is easy to peel off the secondary coating 3 and the tertiary coating 4 from the primary coating 2, thereby improving the workability at the time of connection and enabling a connection with higher reliability. Becomes

[0026]

Next, the present invention will be described more specifically with reference to examples. The Young's modulus is a value measured at a distance between gauge points of 25 mm, a tensile speed of 1 mm / min, and 2.5% elongation measured according to JIS K 7162.

Example 1 G having a core diameter of 100 μm, a cladding diameter of 125 μm, and an NA of 0.26 was used.
On an I-type optical fiber, Young's modulus is 120kg / mm ² at 23 ° C,
A urethane acrylate-based UV-curable resin (A) of 200 kg / mm ² was coated at -30 ° C. so as to have an outer diameter of 140 μm, and then cured by irradiating UV rays to form a primary coating.
Then, a Young's modulus of 0.1 kg / mm ² at 23 ° C.
1.0 kg / mm ² urethane acrylate UV-curable resin (B1) at 70 ° C, Young's modulus 70 kg / mm ² at 23 ° C,-
A urethane acrylate UV-curable resin (C1) of 150 kg / mm ² at 30 ° C was applied to an outer diameter of 280 μm and 500 mm, respectively.
After coating in order so as to have a thickness of μm, each coating was co-cured by irradiating ultraviolet rays to form a secondary coating and a tertiary coating to obtain an optical fiber core.

Subsequently, a vinyl chloride resin was extrusion-coated on the outer periphery of the obtained optical fiber core wire while an aramid fiber was applied as a strength member to produce an optical single-core cord having an outer diameter of 0.22 mm. FIG. 2 is a cross-sectional view showing the optical single-core cord obtained in this manner.
Denotes a tensile strength member, and 7 denotes a jacket made of a vinyl chloride resin.

Example 2 An optical fiber having a core diameter of 100 μm and a cladding diameter of 125 μm was used.
Using a GI type optical fiber of m, NA 0.28,
As a material for forming a tertiary coating, instead of urethane acrylate-based UV-curable resin (C1), the Young's modulus is 4 at 23 ° C.
5 kg / mm ^2, except for using 90 kg / mm ² of urethane acrylate ultraviolet curable resin (C2) at -30 ° C., Example 1
An optical fiber core was manufactured in the same manner as described above, and an optical single-core cord was manufactured using the same in the same manner as in Example 1.

Examples 3 to 7 An optical fiber core was manufactured in the same manner as in Example 1 except that the type of the optical fiber and the coating diameter of each coating were changed as shown in Table 1. In the same manner as in Example 1,
Optical single core cord was manufactured.

In order to examine the temperature characteristics of the optical fiber core and the optical single-core cord obtained in each of the above embodiments, the wavelength 0.85
Transmission losses at 23 ° C. and -30 ° C. in μm were measured. For the optical fiber core, the increase in transmission loss due to the lateral pressure was also measured. In this measurement of the increase in side pressure transmission loss, the optical fiber core was sandwiched between two pressing plates (length 250 mm, width 100 mm) through sandpaper (# 400) over a length of 500 mm. A 5 kg load was applied from above the pressing plate.

The measurement results are shown in Table 1 together with the configuration of the optical fiber.

In Table 1, what was shown as a comparative example was:
Comparative Example 1 was formed on the primary coating formed in the same manner as in Example 1,
5.0 kg / mm ² Young's modulus at 23 ° C., coated -30 ° C. with 20.0 kg / mm ² of urethane acrylate ultraviolet curable resin (B2) so that the outer diameter is 500 [mu] m, cured by irradiation with ultraviolet light Comparative Examples 2 and 3
However, in this case, the type of the optical fiber or the type of the optical fiber and the coating diameter of the primary coating were changed, and Comparative Example 4 was a urethane acrylate-based ultraviolet curable resin (B1) as a material for forming the secondary coating. prepared, 1.5 kg / mm ² Young's modulus at 23 ° C., except for using 5.0 kg / mm ² of urethane acrylate ultraviolet curable resin (B3) at -30 ° C., in the same manner as in example 1 in place of Examples of the optical fiber cores described above are all shown for comparison with the present invention.

[0034]

[Table 1] As is apparent from these results, the optical fiber core wire according to the present invention and the optical single-core cord manufactured using the same have excellent temperature characteristics regardless of the type of optical fiber, Excellent lateral pressure characteristics.

[0035]

As described above, according to the optical fiber ribbon of the present invention, a secondary coating made of a UV-curable resin having a low Young's modulus and a secondary coating having a high Young's modulus are provided on the non-peelable primary coating. Since a tertiary coating made of an ultraviolet-curable resin is provided in order, it is possible to suppress a change in temperature and a variation in transmission loss due to single-core coding regardless of the type of optical fiber.

Further, according to the method of manufacturing the optical fiber core wire of the present invention, after the ultraviolet curable resin for forming the primary coating is coated and cured, the ultraviolet curable resin for forming the secondary coating and the tertiary coating is formed. Coating in order, and then co-curing, so that the secondary coating and the tertiary coating can be easily peeled off from the primary coating, and the workability and reliability at the time of connection with a simple crimping connector have been further improved. It becomes possible to manufacture an optical fiber.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an optical fiber core of the present invention.

FIG. 2 is a cross-sectional view showing an example of an optical single-core cord manufactured using the optical fiber core of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical fiber 1a ... Core 1b ... Cladding layer 2 ... Primary coating 3 ... Secondary coating 4 ... Tertiary coating

Claims (4)

[Claims] 1. A Young's modulus having good adhesion to the cladding layer of an optical fiber is 50 kg / mm at room temperature.
^{2 ~200kg} / mm comprising ^two ultraviolet curable resin non-releasing of the primary coating, the release of high Young's modulus is 0.02 kg / mm ² UV-curable ~1.0kg / mm ² at room temperature to the primary coating secondary coating made of a resin, the Young's modulus at room temperature 40 kg / mm ² to 100 kg
An optical fiber core comprising a tertiary coating made of a UV-curable resin having a thickness of / mm ² . 2. The optical fiber core according to claim 1, wherein the thickness of the primary coating is 5 to 25 μm. 3. The optical fiber tape according to claim ₁ , wherein the ratio r ₂ / r ₁ of the finished diameter r ₂ of the secondary coating to the finished diameter r ₁ of the primary coating is 1.4 to 2.0. Cord. 4. A Young's modulus having good adhesion to the cladding layer of the optical fiber is 50 kg / mm at room temperature.
^{2 ~200kg} / mm ² of the ultraviolet curable resin was coated, after curing by irradiation with ultraviolet rays, thereon, the better Young's modulus of the release property to the coating at room temperature 0.05 kg / mm ² to 1.0 kg / mm ²
40 kg / mm ² UV-curable resin and a Young's modulus at room temperature of
A method for producing an optical fiber, characterized in that a UV curable resin of up to 100 kg / mm ² is coated in order, and then these coatings are irradiated with UV light to be co-cured.