JPS62205304A - Tape type optical fiber coated with ultra violet curable resin - Google Patents

Abstract

PURPOSE:To obtain the titled fiber capable of realizing an excellent optical transmission characteristic at a low temperature, even if resins which increase Young's modulus at the low temperature are used, by specifying Young's modulus of the UV curable resins which are used for the 1st and 2nd coatings at the temps. of 25 deg.C and -30 deg.C respectively. CONSTITUTION:The Young's modulus of the UV curable resin which is used for the 1st coating 2 of the tape type optical fiber at 25 deg.C and -30 deg.C are 10-100kg/cm<2> and 100-20,000kg/cm<2> respectively. The Young's modulus of the UV curable resin used for the 2nd coating 3 at 25 deg.C and -30 deg.C are 10-20,000kg/cm<2> and 10-60,000kg/cm<2>, respectively. In the past, the resin which increases the Young's modulus at the low temp. is used for the 1st and 2nd coatings, thereby increasing the loss of the optical transmission. However, excellent optical transmission characteristics at the low temp. may be realized by specifying the Young's modulus to the prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tape-type optical fiber coated with an ultraviolet curing resin. More specifically, it relates to a silica glass-based tape-type optical fiber coated with a resin and having excellent low-temperature characteristics.

[Prior Art] A silica glass optical fiber is provided with a multilayer resin coating to protect the optical fiber from external forces and impacts. These resin coatings usually consist of a primary coating placed directly on the optical fiber and a secondary coating placed on the outside of the primary coating, and if necessary, a buffer layer is provided between the primary coating and the secondary coating. Sometimes it is.

Also known is a tape-type optical fiber in which a plurality of such optical fibers are arranged in parallel and coated and fixed with a resin.

Optical fibers are used in various environments and are improved to have the characteristics required in each environment. For example, when used at low temperatures (=10° C. or lower) such as in extremely cold regions, optical transmission loss increases. This phenomenon is thought to be due to microbending occurring in the optical fiber due to shrinkage of the resin coating.
As the next coating, a soft resin is used which has a Young's modulus of 1 to LOO kg/cd at room temperature and whose Young's modulus hardly changes even at low temperatures (approximately -30° C.).

[Problems to be solved by invention] However,
Even if a resin having a small Young's modulus even at low temperatures is used as the primary coating material, the optical fiber's optical transmission loss at low temperatures still increases. This phenomenon is also observed in tape-type optical fibers.

The present inventors have found that even if the resin has a specific Young's modulus, even if the Young's modulus increases at low temperatures, it will not cause a significant increase in optical transmission loss as described above, and will hardly change the Young's modulus. We have discovered the surprising fact that the increase in loss at low temperatures is smaller than those without, and have completed the present invention.

[Means for Solving the Problems] That is, the present invention provides a method for fixing a plurality of quartz glass-based optical fibers, each of which has a primary coating and a secondary coating formed with an ultraviolet cured product of an ultraviolet curable resin, with a resin. It is a tape type optical fiber, and the UV cured product of the primary coating is heated at 25℃.
It has a Young's modulus of 10~1ookg/cm2 and 1oo~20,000kg/at at -30℃ and 10~20,000kg/at at 25℃ and -80℃, respectively. The present invention relates to an ultraviolet curing resin coated tape type optical fiber having a Young's modulus of ca and 10 to fin, 000 kg/cl.

[Operations and Examples] A major feature of the resin-coated tape optical fiber of the present invention is that a resin whose Young's modulus increases at low temperatures, which was conventionally thought to increase optical transmission loss at low temperatures, is used for the primary coating.
An ultraviolet curing resin can be used as the resin for the subsequent coating.

It is not yet clear why the increase in optical transmission loss is reduced when an ultraviolet curable resin having a specific temperature dependence of Young's modulus is used as the primary and secondary coatings, but as shown in the examples described below, You can get excellent results.

The structure and module of the optical fiber to which the present invention is directed does not matter, as long as it is a silica glass tape-type optical fiber.

As mentioned above, the ultraviolet curable resin used for forming the primary coating, which is an important feature of the present invention, has an ultraviolet ray cured product having a weight of 10 to 100 kg/cIil, preferably 30 to 80 kg/at, at 25°C. Preferably has a Young's modulus of 50 to 80 kg/c# and -30
Young's modulus increases at a low temperature of 100 to 20,0
00kg/CI, preferably 5 (10-5,00
0kg/c♂, especially preferably 1,000~3,
000kg/c4. Those having Young's modulus temperature dependence in this range surprisingly have better optical transmission characteristics at low temperatures than conventional ones. Examples of the UV-curable resin for forming the primary coating include UV-curable resins such as urethane acrylate, polybutadiene acrylate, silicone acrylate, polyester acrylate, epoxy acrylate, and polyether acrylate. Among these, urethane acrylate resins are preferred, and those containing urethane acrylate oligomers containing at least one polyester polyol unit are particularly preferred. for example,
The polyol component is polytetramethylene glycol (PT
MG) and a polyester polyol of adipic acid and 1,6-hexanediol, the incyanate component is isophorone diisocyanate (IPDI), and the acrylate component is 2-hydroxyethyl acrylate (HE
A) is preferred.

The cured product of the ultraviolet curable resin used for forming the secondary coating has a temperature of 10 to 20°C at 25°C and -30°C.
, 000kg/d and 10-80, 000k
Any material having a Young's modulus of g/+J may be used. Specific examples include urethane acrylate, polybutadiene acrylate, silicone acrylate, polyether acrylate, polyester acrylate, epoxy acrylate, cationically polymerized epoxy resin, unsaturated polyester, or a mixture of these. Examples include ultraviolet curable resins.

In the present invention, a buffer layer may be provided between the primary coating and the secondary coating. As the resin used to form the buffer layer, ultraviolet curable resins such as urethane acrylate, silicone acrylate, polybutadiene acrylate, polyether acrylate, and polyester acrylate are preferably used, and the Young's modulus of the cured product is 10 to 1,000 kg/cd at 25°C, preferably 10
~100 kg/cJ is suitable.

The thickness of the primary coating, buffer layer, and secondary coating varies depending on the optical fiber structure, etc., but each has a thickness of lO to 20
It is usually selected in the range of 0, 0 to 300, and 10 to 500.

Each of these ultraviolet curable resins is made into a varnish by adding and blending an appropriate reaction diluent, photopolymerization initiator, pigment, etc. to each resin. Examples of reaction diluents include IIEA, phenoxyethyl acrylate, IPDI, phenyldiethylene glycol acrylate, phenyltriethylene glycol acrylate, lauryl acrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, hexanediol diacrylate, triethene glycol diacrylate, Examples of photopolymerization initiators include neopentyl glycol diacrylate, tetraethylene glycol diacrylate, N-vinylpyrrolidone, and 2-ethylhexyl acrylate. Examples of photopolymerization initiators include l-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, benzophenone,
Examples include, but are not limited to, jetoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropen-1-one, inbutylbenzoin ether, isopropylbenzoin ether, hydroxycyclohexylphenyl ketone, etc. do not have.

Various methods are used to form the primary coating, but for example, an optical fiber obtained by melting and drawing a quartz glass optical fiber base material is passed through a varnish for the primary coating, cured by irradiation with ultraviolet rays, and then coated in the same manner. Another method includes applying and curing a face for a buffer layer and applying and curing a varnish for a secondary coating. Coating conditions and curing conditions may be appropriately selected depending on the type of resin used, coating thickness, line speed, etc.

The resin-coated tape-type optical fiber of the present invention can have a structure as shown in FIG. 1, for example.

In FIG. 1, (1) is an optical fiber, on which is provided a primary coating (a), an optional buffer layer (not shown), and then a secondary coating (3). Bundle several wires (4), usually 5 to 10,
A tape coating layer (5) is provided around them. Examples of the material for the tape coating layer (5) include ultraviolet curable resins such as urethane acrylate, polyester acrylate, epoxy acrylate, cationic polymerizable epoxy resin, and unsaturated polyester, or mixtures thereof.

The Young's modulus of the resin of the tape coating layer is 2,000 to 20,000 kg/am2 at 25°C.
(2.[)00~80,000kg/c at 1℃
m2 is preferred.

Next, the resin-coated tape type optical fiber of the present invention will be explained based on Examples, but the present invention is not limited to these Examples.

Example 1 Polyol component (PTMG + polyester polyol of adipic acid and 1,6-hexanediol), isoanate component (IPDI), and acrylate component (HE A )
A urethane acrylate-based ultraviolet curable resin consisting of (
Grandic PC70G manufactured by Dainippon Ink & Chemicals
) was used as the primary coating material, and PT was used as the secondary coating material.
MG and tolylene diisocyanate) (TDI) and IIE
A mixture of urethane acrylate consisting of A and epoxy acrylate consisting of bisphenol A/epichlorohydrin and acrylic acid (Desolite 950YLOO, manufactured by Nihon Gosei Rubber ■) was used.

A pot in which the Gl-type stone capsule glass optical fiber matrix produced by the VAD method is drawn at a drawing speed of 30 m/min, and the fibers for coating using the above-mentioned method 1 are stored at the same speed as the obtained optical fiber (diameter 125.ca). The primary coating material varnish was applied through the inside, and then cured through an ultraviolet irradiation device with an effective length of 50 cm (effective irradiation time 1 second), and an outer diameter of 20 cm was applied.
A primary coating of 07a was formed.

Subsequently, a two-method coating face was applied and ultraviolet rays were irradiated (effective irradiation time: 1 second) to form a secondary coating with an outer diameter of 300 mm, thereby producing a resin-coated optical fiber strand.

The Young's modulus of each coating layer was as follows.

] Happi coat M! : 75kLr/c+j-30℃ at 25℃
2,200kg/crI secondary coating: 4,500kg/cJ at 25℃-8,500kg/cJ at 30℃
The cJ Guyang's modulus was measured using a festival of about 150. A tanzak-shaped sample with a width of 15 mm was prepared by forming a thick film and curing it by sufficiently irradiating it with ultraviolet rays.This sample was subjected to a tensile test at a tensile speed of 1++ un/min, and the elongation was 2.5%. The tensile modulus at

Five of these optical fibers are lined up and Desolite 950 is used.
Y 100 is used to coat it all at once, and it is cured by irradiating it with ultraviolet rays to form a tape-type optical fiber ~ (0,45++++nX1
．． 13 mm) was produced.

The obtained resin-coated tape type optical fiber is approximately 30 am
Take a bundle and put it in a constant temperature bath at a wavelength of 1.30.11.
When the transmission loss at 111 was measured, the transmission loss at 25°C was 0.50 dB/km, and the transmission loss did not change even when the temperature was lowered by -30°C.

Comparative Example 1 = 11 - Urethane acrylate consisting of PTMG, IPDI and IIEA (Grandic FC708 manufactured by Dainippon Ink & Chemicals, 25°C and -30°C) was used as the primary coating material.
A tape-type optical fiber coated with an ultraviolet curable resin was prepared in the same manner as in Example 1, except that the Young's modulus was 38 kg/ca), and the transmission loss was measured in the same manner as in Example 1. 0.50dB/km,
It was 0.80 dB/Jun at -30°C (loss increase: 0.30 dB/Km).

Comparative Example 2 As the primary coating material, urethane acrylate-based ultraviolet curing resin (Desolite 950x065.25°C manufactured by Desoto Co., Ltd. and Young's modulus at -30°C is 25 kg/c+#, respectively)
A tape-type optical fiber coated with an ultraviolet curable resin was prepared in the same manner as in Example 1 except that 30,000 kg/cd) was used, and the transmission loss was measured in the same manner as in Example 1. It was found to be 0.50 dB at 25°C. /Km, -3
It was 58 dB/km at 0°C (loss increase El: 5
2.5dB/km).

Example 2 = 12 - Ethylene glycol adipate and TDI as primary coating
Urethane acrylate (0GFI manufactured by Mitsubishi Yuka Fine ■) consisting of
A tape-type optical fiber coated with an ultraviolet curable resin was prepared in the same manner as in Example 1 except that 0 kg/ca) was used, and the transmission loss was measured in the same manner as in Example 1.
0.50dB/Km at 5℃, -ao'c te also 0.
It was 50 dI3/Km, and there was no increase in transmission loss.

Example 3 [Effects of the Invention] According to the present invention, a resin coating with excellent optical transmission characteristics is produced, which breaks the conventional wisdom that unless the Young's modulus is low even at low temperatures, the optical transmission loss will be large at low temperatures. An optical tape type fiber can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of one embodiment of the resin-coated tape type optical fiber of the present invention. (Symbols in drawings) (1): Optical fiber (2): Primary coating (3): Secondary coating (1): Optical fiber cable (5): Tape coating layer 1: Optical fiber 2: Primary coating 6: Secondary Coating 4: Optical fiber strand 5: Tape coating layer

Claims (1)

[Scope of Claims] 1. A tape-type optical fiber in which a plurality of quartz glass-based optical fiber strands each having a primary coating and a secondary coating formed with an ultraviolet-cured product of an ultraviolet-curable resin are fixed with a resin, comprising: 1 The next coating UV cured product is 25℃ and -30℃
10~100kg/cm^2 and 100~
It has a Young's modulus of 20,000 kg/cm^2, and 2
The UV-cured material of the next coating is 10-20,000 kg/cm^2 and 10-60 at 25℃ and -30℃, respectively.
A tape-type optical fiber coated with ultraviolet curing resin and having a Young's modulus of ,000 kg/cm^2. 2. The optical fiber according to claim 1, wherein the ultraviolet curable resin for primary coating contains a urethane acrylate oligomer containing at least one polyester polyol unit.