JPS581053B2 - Manufacturing method of multi-component glass fiber for optical communication - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a method for producing a multicomponent glass fiber for optical communications with improved weather resistance.

Conventional multi-component glass fibers for optical communications have a structure with a plastic protective film around the outer periphery.

However, when such glass fibers are exposed to high temperature, high humidity, or water for a long time, they deteriorate, resulting in a decrease in mechanical strength and an increase in light scattering loss.

The cause of this fiber deterioration is that the alkali ions contained in the multi-component glass are eluted and a layer with few alkali ions is formed on the fiber surface, resulting in a difference in the amount of alkali ions between the surface layer and the inside. It is thought that cracks are more likely to occur and the mechanical strength deteriorates.

For this reason, a method has recently been proposed in which a triple crucible is used to simultaneously spin glass fibers and coat the outside with a highly weather-resistant glass layer.

However, the highly weather-resistant glass used in this method has an inner core. Because it has extremely high viscosity at high temperatures compared to clad glass, it is difficult to form into fibers, and the fibers tend to be eccentric with respect to the outer glass layer.

The present invention has been made to solve the above-mentioned drawbacks, and is an optical communication system that prevents fiber deterioration by blocking the reaction between alkali ions in the multi-component glass fiber material and the external atmosphere without inhibiting fiberization. The purpose of the present invention is to provide a method for producing multi-component glass fibers for use in industrial applications.

The present invention will be explained in detail below.

First, multi-component glass is spun into a core using, for example, a double crucible. Form a glass fiber material consisting of a cladding.

Next, after spinning, preferably 0.5 to 1 second after spinning without contact with outside air, a solution containing an organic silane compound as a main component is applied to the glass fiber material by dipping, spraying, etc., followed by heat treatment. A protective film is formed on the outer peripheral surface of a glass fiber material to produce a multicomponent glass fiber for optical communication.

The multicomponent glasses used in the present invention are different for the core and for the cladding, and it is necessary to select the multicomponent glasses for the core and cladding so that the refractive index of the core is greater than the refractive index of the cladding. .

The solution containing an organosilane compound as a main component used in the present invention refers to a solution containing an organosilane compound alone or a mixture of an organosilane compound and an organometallic compound in an organic solvent such as methyl alcohol, ethyl alcohol, or isopropyl alcohol. It is dissolved in alcohol, ethyl acetate, butyl acetate, acetone, toluene, etc., and a solution in alcohol is particularly useful because a uniform coating film can be obtained.

Examples of the organic silane compounds include phenyltrimethoxysilane, phenyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, γ
-Aminopyrtrimethoxysilane, ethyl silicate, and the like.

In addition, the above-mentioned organometallic compound refers to P dissolved in an organic solvent,
B, Zn, Zr, Ti compounds, such as alkoxide compounds of the above metals, acetylacetate compounds,
Examples include organic acid salts.

The protective film formed from a solution containing an organometallic compound in the organosilane compound has excellent weather resistance, so even if exposed to high temperature, high humidity, or water for a long time, the glass fiber will remain intact. It can be effective in completely preventing material deterioration.

The thickness of the protective film in the present invention is usually 100A to 10μ.
It is enough to do it to a certain extent.

The heat treatment conditions in the present invention cannot be absolutely limited depending on the type of organic silane compound used, but the organic solvent in the solution containing the organic silane compound as a main component applied to the fiber material is vaporized, and the organic silane compound is It is desirable to set the temperature at a temperature at which the Si compound and the fiber material chemically bond.

However, according to the present invention, by applying a solution containing an organic silane compound as a main component to the glass fiber material immediately after spinning and heat-treating it, the difficulty of fiberization can be solved.
A protective film with good adhesion and uniform thickness can be formed on the outer peripheral surface of the fiber material without causing eccentricity of the fiber material, and this can reliably block the reaction between the alkali ions in the glass fiber material and the external atmosphere. , high temperature and high humidity,
Alternatively, the glass fiber material inside the protective film can be prevented from deteriorating even if it is exposed to water for a long time.

Therefore, it is possible to obtain a glass fiber for optical communication that has significantly improved mechanical strength and light scattering loss by preventing deterioration of the glass fiber material.

Next, embodiments of the present invention will be described with reference to the drawings.

Example 1 First, as shown in FIG. 1, the inner crucible 1a of the double crucible 1
70% by weight of SiO2, 1.5% by weight of Na2, and C.
Multi-component glass 2 for core with composition ratio of a08.5% by weight
and 74% by weight of SiO2 in the outer crucible 1b.
A multicomponent glass 3 for the crucible having a composition ratio of 2023% by weight of Na and 3% by weight of Ca was housed, the double crucible was heated to 900°C, and the multicomponent glasses 2 and 3 were simultaneously spun to form a core with a core diameter of 60 μm. A glass fiber material 4 having a cladding diameter of 125 μm was formed.

Next, the glass fiber material 4 immediately after spinning is passed through a die 5.
20% by weight of γ contained in the die 5.
- After applying an ethyl alcohol solution 6 containing aminopyltrimethoxysilane to the outer circumferential surface of the glass fiber material 4, it is passed through a heating furnace 7 heated to 450° C. for optical communication having a protective film on the outer circumferential surface. A multi-component glass fiber 8 for use was obtained.

The obtained multicomponent glass fiber for optical communication was cut to create 200 test pieces with a length of 10 cm, and these test pieces were left in an environmental test chamber at a temperature of 60°C and a humidity of 90% for 1000 hours and 10000 hours. After that, the specimen was taken out and the tensile strength of the specimen under each condition was measured to determine the degree of deterioration.

The results are shown as a Weibull distribution as shown in FIG.

In addition, A0 in the figure is the tensile strength distribution of the glass fiber test piece obtained in Example 1 before the deterioration test, A1 is the tensile strength distribution after leaving the same test piece in the environmental tester for 1000 hours, and A2 is the same. Tensile strength distribution after leaving the test piece in the same tester for 10,000 hours, B1 is the tensile strength distribution after leaving the glass fiber test piece without a protective film in the same tester for 1000 hours, B2 is the same as B1 above. This is the tensile strength distribution after a similar test piece was left in the same tester for 10,000 hours.

As is clear from the figure, the multi-component glass fiber for optical communication obtained by the method of the present invention has a lower degree of deterioration when exposed to high temperature and high humidity for a long time compared to conventional glass fiber without a protective film. It can be seen that it is extremely low.

Example 2 30% by weight of γ as a solution containing organic silane as the main component
- Multi-component glass fiber for optical communication having a protective film on the outer peripheral surface by the same method as in Example 1 except that an ethyl alcohol solution containing aminopylmethoxysilane and 5% by weight of tetramethoxytitanate was used. I got it.

The degree of deterioration of the obtained multi-component glass fiber for optical communication was determined by the same test method as in Example 1 above.

The results are shown as a Weibull distribution as shown in FIG.

In addition, A'o in the figure is the tensile strength distribution before the deterioration test in the glass fiber test piece obtained in Example 2, and A'
1 places the same test piece in an environmental test chamber at 60°C and 90% humidity.
A'2 is the tensile strength distribution after leaving the same test piece in the same tester for 10,000 hours.

As is clear from this figure, when a solution containing an organosilane compound and an organometallic compound is used as the solution for forming the protective film, the temperature is higher than that of the glass fiber (Example 1) which has a protection film made of only an organosilane compound. It can be seen that the degree of deterioration is lower when exposed to high humidity for a long time.

As detailed above, according to the present invention, the reaction between the alkali ions in the glass fiber material and the external atmosphere is reliably blocked without inhibiting fiberization, thereby preventing fiber deterioration and providing stable mechanical strength for a long period of time. , it is possible to provide a multi-component glass fiber for optical communication having low optical transmission loss.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing one form of the manufacturing apparatus used in the method of the present invention, and FIG. 2 is a diagram showing the multicomponent glass fiber for optical communication obtained according to Example 1 of the present invention and a conventional glass fiber without a protective film. Figure 3 is a Weibull distribution diagram showing the tensile strength of the glass fiber after being left under high temperature and high humidity for a long time. It is a Weibull distribution diagram showing the tensile strength after being left for a long time. 1...Double crucible, 4...Glass fiber material, 5...
...Dice, 7...Heating furnace, 8...Multi-component glass fiber for optical communication.

Claims (1)

[Claims] 1. A multicomponent glass fiber for optical communications, which is characterized in that a solution containing an organic silane compound as a main component is applied to a glass fiber material after spinning multicomponent glass, and then heated to form a protective film. manufacturing method.