JPH04116609A - Heat resistant optical fiber - Google Patents

Abstract

PURPOSE:To easily peel a coating material from a glass optical fiber and to facilitate connection or terminal processing work by interposing an organometal compound which adds the property of peeling at a boundary between a glass and the jacket material. CONSTITUTION:In this heat resistant optical fiber coated with the jacket material made of organometal polymer composition, the organometal compound which adds the property of peeling from the glass is interposed at the boundary between the glass constituting a fiber and the jacket material, so that the jacket material is easily removed. The organometal polymer has repeating units including at least one or more metals in a molecule and also has at least one or more three-dimensional structural unit as well as an organic group before curing. Thus, the jacket material is easily removed by the terminal processing of the optical fiber or connecting work thereof, and the workability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat-resistant optical fiber, and more particularly to a heat-resistant coating with improved peelability of an organometallic polymer composition coated thereon.

[Prior Art] Optical fibers have been used not only for communications but also in the fields of data processing and measurement. Particularly in this field, there is an increasing demand for heat-resistant optical fibers that can be used at high temperatures, and to meet this demand, optical fibers coated with metals, ceramics, etc. are being considered.

However, metal-coated optical fibers generally tend to suffer from microhend loss if a metal with excellent heat resistance is used, and conversely, if a metal that prevents microhend loss is used, the heat resistance tends to be poor. be.

On the other hand, ceramics are extremely weak against bending due to their poor ductility, and are
It was only used as an extremely thin film coating for ~1000 people. Due to these two reasons, organometallic polymers have been proposed as coating materials that exceed the heat resistance of organic materials. Since this material has an inorganic backbone and an organic material added to its side chain, it maintains flexibility and heat resistance that are between those of inorganic materials and organic materials.

Also, unlike organic polymers such as polyimide, it has the characteristic that inorganic substances remain even if it is thermally decomposed at high temperatures.

[Problems to be Solved by the Invention] The above-mentioned organometallic polymer has an inorganic backbone, and the OH groups present at the end of the polymer may react with glass, so it has poor adhesion with optical fibers. is very good. These two improvements improve mechanical strength and other reliability.

However, on the other hand, the following problems arise in terminal processing and connection work units that require careful removal of the coating.

In fact, because the cured organometallic polymer has excellent chemical resistance, it is extremely difficult to remove the chemical coating.

Additionally, metal-organic polymer coatings are generally harder than organic coatings, so if you try to remove them mechanically,
There is a high possibility of damaging the optical fiber.

Furthermore, even if attempts are made to decompose organic materials through combustion, ultraviolet rays, ozone, etc., inorganic materials remain and, moreover, they have the disadvantage of firmly adhering to the crow.

Therefore, it may be possible to use a mold release agent to eliminate such drawbacks. However, fluorine-containing resins and oils, fatty acids such as stearic acid, metal soaps, hydrocarbon oils, waxes, etc. that are usually used as mold release agents, such as fluorine-containing fats and fluorine-containing foams, may be effective in releasing the mold at an early stage. Yes, but
When used at high temperatures, corrosive gases such as hydrogen fluoride are generated, which significantly reduces the strength of the optical fiber.

In addition, with other mold release agents other than those listed above, the mold release agent may rapidly thermally decompose during the curing process or when used at high temperatures, producing harmful hydrogen and increasing transmission loss, and in some cases may cause bubbles to form in the coating material. , the mechanical strength of the optical fiber may be reduced.

Therefore, if we can provide an organometallic polymer with releasability, it will be possible to easily remove the covering material at the relevant part during optical fiber terminal processing and connection work, and we believe that this will make an extremely large contribution to industry.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a heat-resistant optical fiber that has good peelability from glass.

[Means for Solving the Problems] The heat-resistant optical fiber of the present invention is applied to a heat-resistant optical fiber coated with a coating material made of an organometallic polymer composition.
do. In such an optical fiber, an organometallic compound that imparts releasability from the glass is interposed at the interface between the fiber constituting lath and the coating material, thereby making it easier to remove the coating material.

Here, an organometallic polymer is one that has repeating units containing at least one metal in its molecules, has at least one three-dimensional structural unit before curing, and also has an organic group. be.

Examples of such materials include polytitanocarbosilane, polyorganosilsesquioxane, polyborosiloxane, polysilane, aluminum/phosphonic acid polymer, carborane polymer, and silazane polymer.

However, only a few are commercially available, and are limited to polytitanocarbosilanes, polyorganosilsesquioxanes, polyborosiloxanes, polysilanes, carborane polymers, and the like. However, the range of organometallic polymers defined above is not limited to these.

The chemical structures of typical organometallic polymers are shown in FIGS. 3 to 7. In addition, the polytitanocarbosilanes 2 and 8 shown in FIG. 3 are mostly present, and (B) and (C) are present in small amounts.

On the other hand, as a substance imparting releasability, it is desirable to use a substance that has a certain degree of compatibility with the above-mentioned organometallic polymer and does not easily react with glass. Further, even if peeling occurs in the initial stage, the peeling effect may be lost due to thermal decomposition during use at high temperatures. However, the remaining thermal decomposition products must not adversely affect the properties of the optical fiber. From this point of view, it is desirable that the substance that imparts releasability itself is an organometallic compound. As organometallic compounds that meet this condition, those having a relatively unreactive group such as an alkyl group or a phenyl group in the molecule are preferable.

Among them, those containing at least one alkyl group have been found to be useful.

For example, polysiloxanes containing alkyl groups such as polydimethylsiloxane, polyphenylmethylsiloxane, polyoctylmethylsiloxane, polyofdabcylmethylsiloxane, tetra-n-butoxysilane, tetrakis(2-ethylbutoxy)silane, tetrakis(2-ethylbutoxy)silane, - polyalkoxysiloxanes such as ethylhexoxyS) silane, hexakis(2-ethylbutoxy)dineloxane, and methyltris(triS-butoxysiloxanyl)silane;
Silanes having alkyl groups such as methyltridecylsilane and methyltrioctylsilane, polyalkyloxytitaniums such as tetrastearyloxytitanium, tri-n-
Polyalkoxytitanium polymers such as butoxytitanium monostearate polymers are suitable.

The items listed here are merely examples and are not limited to these as long as they meet the above requirements.

Even if similar groups exist, the decomposition mechanisms of stearic acid, which has a stearyl group, and tetrastearyloxytitanium, which is an organometallic compound, are completely different, and the organometallic compound decomposes more rapidly. At the very least, almost no decomposition was observed during the curing process.

Furthermore, even when heated at high temperatures, the decomposition was extremely slow and no foaming occurred in the coating.

The organometallic compound that imparts this releasability is effective when placed between the organometallic polymer and the glass, but it is also effective when added to the organometallic polymer. In the latter case, the amount added varies depending on the type of polymer and the type of organometallic compound, but is 0.05 to 5.
．． It is preferable to add about 0 parts by weight. If the amount is too small, the peeling effect will be poor, whereas if the amount is too large, the effect will be saturated and the peelability will not change, and it will also have a negative effect on the optical fiber performance such as strength and heat resistance. .

[A method for interposing an organometallic compound that imparts releasability to the coating material at the interface between the working glass and the coating material is to add an organometallic compound that imparts releasability to the organometallic polymer composition. Alternatively, an organometallic compound that imparts releasability may be applied to the optical fiber in advance, and then the organometallic polymer composition may be coated. When an organometallic compound that imparts peelability is present at the interface between the glass and the coating material, the peeling force becomes weaker because the adhesion between the glass and the coating material, mainly electrostatic bonds, hydrogen bonds, and van der Waals forces, are inhibited. I think this is because it is done.

First, the heat-resistant optical fiber of the present invention is produced by coating the outer periphery of an optical fiber with a composition made of an organometallic polymer to which an organometallic compound that imparts peelability is added, using an ordinary coating die, and then heating the fiber in a heating furnace. It is obtained by curing the composition by passing it through.

FIG. 1 shows an optical fiber drawing line for obtaining such a heat-resistant optical fiber.

An optical fiber 2 is produced by heating the preform 1 in a drawing furnace 3 to bring it into a molten state. The optical fiber 2 passes through a coating die 4, where it is coated with an organometallic polymer 13 doped with an organometallic compound that imparts releasability. The optical fiber coated with the organometallic polymer 13 is led to a heating furnace 5, where the coating material is cured by heating and fixed to the optical fiber. Note that it may be fixed by irradiating UV (ultraviolet light).

After being fixed, the optical fiber wire 7 is switched from the direction of gravity to the horizontal direction by the capstan 6, and is wound around a bobbin (not shown).

Next, the heat-resistant optical fiber of the present invention is prepared by pre-coating the optical fiber with an organometallic compound that imparts peelability by diluting it with a solvent or the like, and then coating the organometallic polymer composition.
It can also be obtained by heating and curing in a similar manner.

FIG. 2 shows a modified example of an optical fiber drawing line for obtaining such a heat-resistant optical fiber. The difference from FIG. 1 is that the optical fiber 2 is pre-tied before being coated with the organometallic polymer.
It passes through a coating die 8, where an organic metal compound 14 having peelability is applied, and the optical fiber coated with this organic metal compound 14 is led to a preheating furnace 9 and solidified.
The organometallic compound having release properties is removed from the organometallic polymer 15 in the subsequent coating.

As described above, in the present invention, an organometallic compound that imparts releasability to the coating material is interposed at the interface between the glass and the coating material. Therefore, even if the organometallic material has excellent chemical resistance and it is difficult to chemically remove it directly, the action of the organometallic compound at the interface will cause the organometallic Bo1. It becomes possible to indirectly remove +7.

Further, since the interposed organometallic compound is softer than the organic coating material, even if an attempt is made to remove it by mechanical methods, no damage will be caused to the optical fiber.

Furthermore, if organometallic compounds are tried to decompose by combustion, ultraviolet light, osin, etc., or if they are used at high temperatures for a long time, they will undergo thermal decomposition and turn into inorganic substances. Unlike organic compounds, which produce different decomposition products depending on the thermal history conditions, organometallic compounds slowly carbonize or volatilize, resulting in the formation of decomposition products in the film. There will be no occurrence of bulges, etc. For this reason,
Fino has no negative effects and does not adhere strongly to the glass.

Further, even when used at high temperatures, corrosive gases are not generated unlike mold release agents, and the strength of the optical fiber is not impaired.

Therefore, it becomes possible to easily remove the covering material at the relevant portion during optical fiber terminal processing and connection work, making an extremely large contribution to industry.

The organometallic polymer composition may contain fillers, colorants, reinforcing fibers, etc. as necessary.

Further, these organometallic polymer compositions can be applied after being melted by heating, but they can also be applied as a paint dissolved in an organic solvent.

Additionally, a carbon coating may be applied prior to coating with the organometallic polymer composition to improve the strength and long-term reliability of the transmission properties of the fiber.

[Example code] The present invention will be explained in detail below.

Example 1 A composition prepared by adding 20 parts by weight of fumed silica and 1.0 parts by weight of tetrastearoxytitanium to 100 parts by weight of polytitanocarbosilane was diluted with a mixed solvent of xylene and methylcellosolve. A normal single-mode quartz preform is drawn to an outer diameter of 125 μm in a drawing furnace at approximately 2000°C, and the above paint is applied to a thickness of 1 mm using a painting die.
It was coated to a thickness of 0 μm, passed through a heating furnace at 400° C. to harden it, and then wound onto a bobbin).

The curing was sufficient and the adhesion was also good. Moreover, the adhesiveness between the glass fiber and the coating material was such that it could be peeled off without using a special tool. The transmission loss is almost the same as that of ordinary single mode optical fiber, and at 400℃,
The increase in transmission loss after 100 hours was also as small as 0.05 dB/km.

Furthermore, the tensile strength was 4 kgf on average, which was slightly inferior to that of ordinary plastic-coated optical fibers, but was approximately the same as that of the case where no peelability was imparted.

Example 2 A composition in which 70 parts by weight of zirconia and 2 parts by weight of tri-butoxytitanium monostearate bolima were added to 100 parts by weight of polymethylsilsesquioxane instead of the polytyranocarbosilane composition of Example 1. was diluted with a mixed solvent of xylene and methylcellosolve. A sample was produced in the same manner as in Example 1.

The peeling force was not much different from Example 1, and the fiber properties were also almost the same.

Example 3 Instead of the polytitanocarbosilane composition of Example 1,
A composition prepared by adding 50 parts by weight of silicon carbide and 1 part by weight of polymethyl silicone oil to 100 parts by weight of polyborosiloxane was diluted with a mixed solvent of xylene and methylcellosolve.

A sample was produced in the same manner as in Example 1. The peeling force was not much different from Example 1, and the fiber properties were also almost the same.

Example 4 A composition obtained by removing tetrastearoxytitanium from the composition of Example 1 was diluted with a mixed solvent of xylene and methylcellosolve. The same preform as in Example 1 was drawn in a drawing furnace to an outer diameter of 125 μm, pre-coated with a xylene solution of tetrastearoxytitanium, and immediately coated with the above composition to a thickness of 10 μm. The film was passed through a heating furnace to harden and then rolled up.

The peeling force was not much different from Example 1, and the fiber properties were also almost the same.

Example 5 50 parts by weight of fused quartz and 0 parts by weight of methyltridecylsilane were added to 100 parts by weight of the polyphenylsilsesquioxane of Example 2.
．． The composition to which 05 parts by weight was added was diluted with a mixed solvent of xylene and methylcellosolve.

A sample was produced in the same manner as in Example 1. Although the peeling force was slightly greater than that of Example 2, peeling occurred at the interface between the glass and the coating material.

Example 6 The same as Example 5 except that 5 parts by weight of methyltridecylsilane of Example 5 was added. A sample was produced in the same manner as in Example 1. The peeling force was not much different from Example 2. The average tensile strength of optical fiber is 3. Although the performance was slightly low (Okgf), it showed sufficient performance for practical use.

Comparative Example 1 Same as Example 1 except that tetrastearoxytitanium was removed from Example 1. The fiber performance etc. were not much different from Example 1, or the fiber and the coating material were adhered and could not be separated.

Comparative Examples 2 and 3 In Examples 2 and 3, the substance that imparts releasability was similarly removed, and results similar to those of Comparative Example 1 were obtained, respectively.

Comparative Example 4 The same as Example 5 except that 0.04 part by weight of methyltridecylsilane of Example 5 was added. Although the fiber performance etc. were not much different from Example 1, there was adhesion between the fiber and the coating material, and the peeled surface showed cohesive failure.

Comparative Example 5 The same as Example 6 except that 6 parts of methyltridecylsilane of Example 6 was added. Average fiber strength is 3kg
It showed a considerable decrease to less than f.

[Effects of the Invention] As described above, the present invention provides the following excellent effects.

(1) According to the heat-resistant optical fiber according to claim 1, since an organometallic compound that imparts peelability is interposed at the interface between the glass and the coating material, the coating material can be easily peeled off from the glass optical fiber. This makes connection and terminal processing easier.

(2) According to the heat-resistant optical fiber according to the second aspect, since a commercially available organic metal polymer is used, it is easy to put it into practical use.

(3) According to the heat-resistant optical fiber according to claim 3, since an organometallic compound containing at least one alkyl group is used as the organometallic compound that imparts peelability, the properties of the optical fiber are not adversely affected. The releasability of the coating material can be improved.

(4) According to the heat-resistant optical fiber according to claim 4, the amount of the organometallic compound that imparts peelability is 0.05 to 5.
．． Since the amount is 0 parts by weight, the peeling effect can be enhanced without impairing the optical fiber performance.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an optical fiber drawing furnace for manufacturing the heat-resistant optical fiber of the present invention, and FIG. Schematic diagram, FIG. 3 is a chemical structure diagram of polytitanocarbosilane, which is an example of the organometallic polymer according to the present invention, FIG. 4 is a chemical structure diagram of polyorganosilsesquioxane, and FIG. The chemical structure diagram of siloxane, Figure 6 is also the chemical structure diagram of carborane polymer, and the seventh country is also the chemical structure diagram of silazane polymer. Figure 1: Drawing lines of this embodiment -f-3i -CH m- Figure 3: Drawing lines of a modified example Figure 2: Structure of main cylinder resesquion N+ Figure 4: Figure 5

Claims (1)

[Claims] 1. In a heat-resistant optical fiber coated with a coating material made of an organometallic polymer composition, at the interface between the glass constituting the optical fiber and the coating material,
A heat-resistant optical fiber characterized by interposing an organic metal compound that imparts releasability to glass. 2. The organometallic polymer is polytitanocarbosilane, polyorganosilsesquioxane, polyborosiloxane,
The heat-resistant optical fiber according to claim 1, characterized in that it is made of either polysilane or carborane polymer. 3. The organometallic compound is polyalkylsiloxane, polyalkoxysiloxane, silane having an alkyl group,
The heat-resistant optical fiber according to claim 1 or 2, characterized in that it is made of polyalkyloxytitanium or polyalkoxytitanium polymer. 4. By adding the organometallic compound to the organometallic polymer composition, the organometallic compound is interposed at the interface between the glass and the coating material, and the amount of the organometallic compound added to the organometallic polymer composition is controlled. 0.05-5.0
The heat-resistant optical fiber according to any one of claims 1 to 3, which is a weight part.