JP4794773B2 - Optical fiber manufacturing method and manufacturing apparatus - Google Patents

Description

【００１４】
【表２】

【００１５】
結果を表３に示す。なお表中の「―」は、未実施を示す。
【００１６】
【表３】

【００１７】
表３の結果から明らかなように、比較例の場合高速線引き下において、均一な被覆が困難である。特に比較例１では線引き長７００ｋｍですでにセカンダリ外径が、大きく変動しているのに対し、本発明の方法によれば１５００ｍ／ｍｉｎの高速でも１０００ｋｍ全長にわたって安定した被覆層が得られ、特に実施例３の場合は１３００ｋｍ全長にわたって極めて安定した被覆層が得られることがわかる。
【００１８】
【発明の効果】
本発明は、以上のように１０００ｍ／ｍｉｎ以上の高速線引き速度で、光ファイバ上に２層の硬化型の樹脂被覆をタンデムに塗布して、紫外線照射により硬化させる際に、プライマリ被覆工程で発生しその被覆層表面に付随している樹脂揮発成分の悪影響を除去した後にそれ以降の樹脂被覆を行うので、塗布すべき液状の樹脂の濡れ性が低下することがなく、高速線引きでかつ長尺に長さ方向に均一な被覆を施すことができる。本発明方法によれば外径変動がなく、長時間連続して安定した条件で均一な２層被覆ができる。本発明の被覆光ファイバの製造装置は、上記のように光ファイバの製造方法の生産性に大きく寄与し、しかも装置自体は比較的低コストで製作することができる。
【図面の簡単な説明】
【図１】 本発明の光ファイバの製造装置の好ましい１例の概略構造図である。
【図２】 本発明のトラップゲートの１例の拡大斜視図である。
【図３】 本発明のトラップゲートの他例の拡大斜視図である。
【図４】 本発明のトラップゲートのさらに他例の拡大斜視図である。
【図５】 本発明の通常の光ファイバの断面図である。
【図６】 本発明の従来の光ファイバの製造装置である。
【符号の説明】
１ 炉
２、５ 冷却装置
３ プライマリ材ＵＶ樹脂塗布装置
４、７ 紫外線照射装置
６ セカンダリＵＶ樹脂塗布装置
８ トラップゲート
８ａ 進入孔
８ｄ 凸形部
１０ 光ファイバ母材
１２ 光ファイバ裸線
１３、１４ 光ファイバ
４０ 光ファイバ
４１ 光ファイバ裸線
４２ プライマリ材被覆層
４３ セカンダリ材被覆層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical fiber manufacturing method and apparatus capable of uniform coating even under high speed drawing.
[0002]
[Prior art]
As shown in a sectional view in FIG. 5, a general optical fiber has a primary material coating layer 42 having a low Young's modulus made of UV (ultraviolet curable) resin on the first optical fiber bare wire 41 and two layers. It is a structure in which a two-layer coating of a secondary material coating layer 43 made of UV resin and having a high Young's modulus is applied to the eyes. FIG. 6 shows a schematic structural diagram of a conventional typical drawing apparatus for manufacturing the optical fiber 40. In FIG. 6, 1 is a furnace for drawing the optical fiber preform 10 by heating, and 2 is a cooling device disposed immediately below the optical fiber preform 10, and a bare optical fiber 12 drawn through a tube supplied with He is passed through it. It is like that. Reference numeral 3 denotes a pressure die type primary material UV resin coating apparatus, in which a pressurized liquid primary material UV resin is supplied, and the resin is coated on the bare optical fiber 12 passing therethrough. Reference numeral 4 denotes an ultraviolet irradiation device for curing the primary material UV resin applied on the bare optical fiber 12, and a primary material UV resin coating layer is formed on the bare optical fiber 12 by passing therethrough. Reference numeral 5 denotes a curing device for cooling the primary material-covered wire that has been heated and heated, and is installed as necessary. 6 is a secondary material UV resin coating device, and 7 is an ultraviolet irradiation device for the secondary material UV resin, which is the same kind as the primary material UV resin coating device 3 and the primary material ultraviolet irradiation device 4, respectively. A secondary material coating layer of UV resin is formed on the optical fiber 13 covered with the primary material. Thereafter, the optical fiber 14 coated with two layers is wound around a bobbin.
[0003]
In recent years, in the world of communication, the amount of information transmitted has increased dramatically, and the development of optical communication infrastructure for that purpose has become an urgent issue worldwide. Against this background, a great demand for optical fibers has been generated for several years, and further improvement in optical fiber productivity is required from the viewpoint of supply. Speeding up is essential. However, when the drawing speed of the optical fiber is increased, particularly at a drawing speed of 1000 m / min, when a certain drawing length is exceeded by continuous drawing production, the diameter of the optical fiber 14 after the coating of the secondary material coating layer (secondary diameter) is increased. ) Has been found to become a problem due to the phenomenon of sharp thinning. Moreover, when the phenomenon that the secondary diameter sharply narrows occurs, the resin component is deposited around the fiber entrance hole of the secondary material coating layer die of the UV resin coating device 6 at the same time, and the deposition amount increases. It was found that it forms a heap-like shape like a dome. As a result of well observing these phenomena, the following was confirmed.
The dome-shaped deposit was collected and measured by FTIR (Fourier transform infrared absorption analysis). As a result, it was confirmed that the deposit was almost the same as the primary material UV resin coating component.
The phenomenon in which the secondary diameter sharply decreases occurs when the dome-shaped deposit grows to some extent and comes into contact with the primary material covered wire (optical fiber 13). It will not happen if there is no sediment.
As a result of intensive studies based on these results, the present inventors have obtained the following knowledge.
That is, as a UV resin used as a coating material, a polyether polyol-based urethane acrylate resin or the like is generally used, but when this material has a high resin temperature due to a polymerization exothermic reaction during curing by UV irradiation, It has been observed that volatiles are generated upon curing. In particular, at the time of drawing, after the primary material coating layer is applied with the apparatus shown in FIG. 6 and UV irradiation is performed, the optical fiber 13 is attached to the secondary material UV resin coating apparatus while this volatile matter is in the gaseous state and attached to the vicinity of the surface of the primary coating layer. When led to 6, volatiles accumulate around the fiber entrance hole of the secondary material die, and a dome state is obtained. When the wire drawing is continued for a long time, the deposit formed by the deposition of the volatiles grows greatly and comes into contact with the primary material-covered wire. Therefore, it is estimated that a part of the deposit adheres to the surface of the primary material covered wire, the wettability of the liquid secondary material resin coating layer to the primary covered wire is deteriorated, and it is not applied. Thus, it is considered that a phenomenon in which the secondary outer diameter is reduced occurs.
[0004]
The phenomenon that the secondary diameter decreases sharply becomes more pronounced as the linear velocity of the optical fiber increases. For this reason, high-speed drawing cannot be performed and productivity is lowered. Moreover, since the secondary coating diameter fluctuates, it becomes a factor that causes various problems such as poor outer diameter and a decrease in mechanical strength.
The influence of volatiles on drawing is also described in, for example, Japanese Patent Application Laid-Open Nos. 8-262285 and 11-35344. JP-A-8-262285 is characterized by using a resin having a volatilization rate of volatiles generated from the primary material of 0.3 wt% / min or less, and the volatiles meant here are contained in the resin. The vapor pressure of the monomer component affects the volatilization rate. In Japanese Patent Laid-Open No. 11-35344, the generated gaseous volatile component is cooled and liquefied to improve the influence of volatile matter. In addition, volatile substances can be removed with a propellant gas. In Japanese Patent Laid-Open No. 11-35344, the volatile matter is a comparative low molecular weight unpolymerized component, and a specific monomer (isobornyl acrylate) is mentioned as a specific example.
[0005]
However, as described in accordance with FIG. 6 above, the problem is that not the specific resin component but almost the same component as the primary material resin is deposited on the secondary die during high-speed and continuous long-time drawing. And it is newly understood by analysis, and this is considered to be the main cause. In addition, since the deposition of the resin occurs earlier as the primary lamp illuminance is higher, it is considered to be caused by the higher temperature due to the polymerization exothermic reaction due to ultraviolet irradiation. Certainly, the coating of the primary material and cooling after ultraviolet irradiation generates volatiles. A certain effect can be obtained for the suppression.
However, when the drawing speed is increased, the time for passing through the cooling section is naturally shortened, and the cooling effect is limited. In order to increase the cooling effect, there are means such as increasing the length of the cooling section and greatly increasing the capacity of the cooling device, but these are all costly because they improve the drawing device itself. It will be.
We also considered changing or removing specific monomer components or compositions in the resin, but the deposition of the primary components on the secondary dies in question, to some extent, can be prevented. could not.
[0006]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a method of manufacturing a coated optical fiber capable of uniform coating under high speed drawing.
Another object of the present invention is to provide a method for producing a coated optical fiber that can perform uniform coating under stable conditions even when wire drawing and two-layer coating by a tandem method are performed continuously for a long time. .
A further object of the present invention is to provide an optical fiber coating apparatus suitable for use in the above-described optical fiber manufacturing method.
[0007]
The above object of the present invention has been achieved by the following means.
That is, the present invention
(1) A method of manufacturing an optical fiber in which two layers of UV curable resin coating are applied on an optical fiber at a drawing speed of 1000 m / min or more. The first layer is applied and cured by UV irradiation. A half-type trap gate for removing volatiles generated during curing by ultraviolet irradiation is provided in front of the second coating layer device for applying and curing the eye, and the one layer is provided at the center of the trap gate. A fiber entrance hole through which an optical fiber coated with eyes is formed parallel to the traveling direction of the optical fiber, and the trap gate is removed during drawing of the optical fiber to remove the deposited volatile matter. A method for producing a multi-layer coated optical fiber, wherein the optical fiber can be drawn again and continued to be drawn after
(2) A method of manufacturing an optical fiber in which two layers of ultraviolet curable resin coating are applied on an optical fiber at a drawing speed of 1000 m / min or more. The first layer is coated and cured by ultraviolet irradiation. When the eye is applied and cured, a trap gate is provided in front of the second coating layer device, and the shape of the convex portion in which the fiber entrance hole of the trap gate is formed is a divergent shape having a substantially convex cross section. And a method of manufacturing an optical fiber, wherein the fiber entrance hole is formed in parallel with a traveling direction of the optical fiber,
( 3 ) In the item (1) or (2), the inner dimension of the fiber entrance hole of the trap gate is set to +0.05 to +0.5 mm of the outer diameter of the first coating layer at the narrow opening. The manufacturing method of the optical fiber as described,
( 4 ) A device for applying a two-layer ultraviolet curable resin coating on an optical fiber, the first layer being coated and cured by ultraviolet irradiation, and then the second layer being coated and cured. Before the layer device, a trap gate for removing volatiles generated during curing by ultraviolet irradiation is provided, and the trap gate is a halved type that can be removed and reattached during drawing of the optical fiber, An apparatus for producing a multi-layer coated optical fiber, wherein a fiber entrance hole through which the optical fiber coated with the first layer is passed in the center is formed parallel to the traveling direction of the optical fiber;
(5) A device for applying a two-layer ultraviolet curable resin coating on an optical fiber, the first layer being coated and cured by ultraviolet irradiation, and then the second layer being coated and cured. A trap gate is provided in front of the layer device, and a cross section in which the fiber entrance hole of the trap gate is formed has a substantially convex divergent convex portion, and the fiber entrance hole is a travel of the optical fiber. An optical fiber manufacturing apparatus characterized by being formed parallel to the direction, and (6) the inner dimension of the fiber entrance hole of the trap gate is +0.05 of the outer diameter of the first coating layer at the narrow opening. The apparatus for producing an optical fiber according to the item ( 4 ) or (5), characterized in that the thickness is set to ~ + 0.5 mm.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the primary component deposition phenomenon in the secondary die is removed.
The trap gate in the present invention refers to a device or jig for removing volatile components, and has a fiber entry hole. By setting the trap gate entry hole size within a certain range, the passage of the volatiles moving along with the optical fiber along with the surface of the primary material covered wire is blocked and attached to the trap gate to physically remove the volatile components. A member having an action to be removed.
In the present invention, it is called a trap gate, but the name is not particularly limited.
FIG. 1 shows a preferred example of a drawing apparatus provided with a trap gate 8 for removing volatile components of the UV resin of the present invention. In FIG. 1, the same reference numerals as those in FIG. 6 denote the same components unless otherwise specified. In FIG. 1, the trap gate 8 is installed as close as possible to the secondary material resin coating device between the primary coated wire cooling device and the secondary material resin coating device, so that The accompanying volatiles can be blocked and effectively attached to the trap gate for removal.
In addition, by using a halved trap gate, the trap gate can be removed during drawing to remove the deposit even if the deposit accumulates to some extent.
[0009]
In addition, since the deposit accumulates at the center of the entrance hole, the deposit is not accumulated at the center of the entrance hole by making the portion where the entrance hole is formed into a substantially convex divergent shape.
By providing the trap gate, which is a feature of the present invention, in front of the secondary die, the primary covered wire from which volatile substances have been removed can be sent to the secondary die, and a drawing speed of 1000 m / min or more can be provided without providing a special device. Thus, it becomes possible to perform a stable line drawing continuously for a long time. The material of the trap gate is not particularly limited, but SUS304 is preferable from the viewpoint of molding processability, dimensional stability, durability, and the like.
[0010]
This trap gate will be described in more detail . FIG. 2 is an enlarged perspective view of a preferred example of the trap gate 8. A portion indicated by 8a is a fiber entry hole (hereinafter referred to as an entry hole) of the primary covered wire. In addition, in order to prevent volatile components from accumulating inside, the inside of the entrance hole 8a is preferably parallel to the primary covered wire or expanded in the downward direction. The diameter of the entrance hole 8a of the trap gate 8 is preferably the outer diameter of the primary covered wire +0.05 to +0.5 mm, particularly +0.1 to +0 at the narrowest portion, that is, the portion closest to the primary covered wire. .3 mm is preferred. If the size in the entrance hole is too small, the primary covered wire comes into contact with the trap gate and damages the primary layer itself. On the other hand, if the outer diameter of the primary coated wire is too large, the volatile component removal effect itself is significantly reduced.
FIG. 3 is a perspective view of a halved type as another preferred example of the trap gate 8, that is, a trap gate 8 comprising 8b and 8c. When the halved type is used, when the amount of the volatile component deposited on the trap gate is large, it is possible to remove the volatile component even during the drawing and clean it.
FIG. 4 shows another preferred example of the trap gate, which shows a type in which the portion where the entrance hole is formed is formed into a convex portion 8d in cross-sectional shape. In this case, even if volatile substances adhere to the trap gate, they are displaced downward, so that the primary covered wire 13 does not accumulate around the entrance hole.
In the above description, an example of a two-layer resin coating is shown, but it is suitable for a multilayer of two or more layers and a tandem coating, and may be a three-layer coating. A trap gate may be provided with a similar configuration.
Next, the present invention will be described in more detail based on examples.
[0011]
【Example】
The resin-coated optical fiber manufacturing apparatus shown in FIG. 1 or 6 was used to draw an optical fiber having a glass diameter of 125 μm, a primary diameter of 195 μm, and a secondary diameter of 250 μm.
In Example 1, the resin-coated optical fiber manufacturing apparatus shown in FIG. 1 was used to install the half-type trap gate 8 shown in FIG.
In Example 2, the trap gate 8 used in Example 1 was once removed at a drawing length of 750 km, the surface was washed and then attached again, and drawing was continued. The removal time is 10 minutes or less.
Example 3 has an entry hole 8a having an inner diameter of 0.3 mm, and the trap gate 8 shown in FIG. 4 is used except that the periphery of the entry hole is a convex cone (5 mm high, cone bottom part diameter 10 mm). The drawing was performed in the same manner as in 1.
[0012]
In Comparative Example 1, drawing was performed using the resin-coated optical fiber manufacturing apparatus shown in FIG.
In Comparative Example 2, drawing was performed by providing a trap gate having a large inner diameter and an entrance hole having an inner diameter of 0.8 mm instead of the trap gate 8 of the apparatus of FIG.
For each of the examples and comparative examples, the secondary speeds at 700, 1000, and 1300 km were drawn when the coated optical fiber having a length of 1300 km was obtained by changing the linear velocity of the bare optical fiber to 1000, 1200, and 1500 m / min. The fluctuation range of the outer diameter was observed. The results are shown in Table 3. Here, the evaluation is performed in three stages, ◯ is within the outer diameter fluctuation width of 1 μm, Δ is within the outer diameter fluctuation width of 5 μm, and is practically acceptable (pass), exceeding the outer diameter fluctuation width of 5 μm. It was a thing (failed). With respect to the drawing length, when it was confirmed that the variation width of the outer diameter exceeded 5 μm at each drawing length described above (x in the determination), the drawing was terminated at that point.
The drawing condition was based on the condition that the secondary outer diameter was changed by 5 μm or more when the drawing length was 700 km by the method of Comparative Example 1 at a drawing speed of 1000 m / min.
The UV resin of the coating material is a photopolymerizable oligomer having an ultraviolet curable functional group and an average molecular weight of about 1000 to 10,000 which gives the basic physical properties of the coating material, and photopolymerization added for the purpose of dilution (viscosity adjustment) of the resin. And a photopolymerization initiator that absorbs ultraviolet rays to initiate polymerization. In addition, polymerization initiators, antioxidants, ultraviolet absorbers, lubricants, silane coupling agents, and the like are added as necessary.
In this experiment, two kinds of UV resin used for evaluation were used for the primary material and one kind for the secondary material. The primary materials A and B and the secondary material C are all polyether urethane acrylate UV resins, and the physical properties shown in Tables 1 and 2 were obtained by adjusting the average molecular weight and blending ratio of the oligomers. All were obtained from JSR Corporation.
In addition, the volatile component isobornyl acrylate blended with the primary material A is a photopolymerizable monomer, and has the effect of improving the adhesion characteristics of the primary material to the glass fiber by blending it in addition to adjusting the viscosity.
The composition and physical properties of each are as follows.
[0013]
[Table 1]

[0014]
[Table 2]

[0015]
The results are shown in Table 3. In the table, “-” indicates not implemented.
[0016]
[Table 3]

[0017]
As is clear from the results in Table 3, in the case of the comparative example, uniform coating is difficult under high speed line drawing. In particular, in Comparative Example 1, the secondary outer diameter has already fluctuated greatly with a drawing length of 700 km, whereas according to the method of the present invention, a stable coating layer can be obtained over the entire length of 1000 km even at a high speed of 1500 m / min. In the case of Example 3, it can be seen that a very stable coating layer can be obtained over the entire length of 1300 km.
[0018]
【The invention's effect】
The present invention occurs in the primary coating process when two layers of curable resin coating are applied on an optical fiber in tandem at a high drawing speed of 1000 m / min or more as described above and cured by ultraviolet irradiation. Since the subsequent resin coating is performed after removing the adverse effects of the resin volatile components attached to the surface of the coating layer, the wettability of the liquid resin to be applied is not reduced, and high speed drawing and long length are performed. Can be coated uniformly in the length direction. According to the method of the present invention, there is no fluctuation in the outer diameter, and uniform two-layer coating can be performed under a stable condition continuously for a long time. The coated optical fiber manufacturing apparatus of the present invention greatly contributes to the productivity of the optical fiber manufacturing method as described above, and the apparatus itself can be manufactured at a relatively low cost.
[Brief description of the drawings]
FIG. 1 is a schematic structural diagram of a preferred example of an optical fiber manufacturing apparatus according to the present invention.
FIG. 2 is an enlarged perspective view of an example of the trap gate of the present invention.
FIG. 3 is an enlarged perspective view of another example of the trap gate of the present invention.
FIG. 4 is an enlarged perspective view of still another example of the trap gate of the present invention.
FIG. 5 is a cross-sectional view of a normal optical fiber of the present invention.
FIG. 6 is a conventional optical fiber manufacturing apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Furnace 2, 5 Cooling device 3 Primary material UV resin coating device 4, 7 Ultraviolet irradiation device 6 Secondary UV resin coating device 8 Trap gate 8a Entrance hole 8d Convex part 10 Optical fiber preform 12 Optical fiber bare wire 13, 14 Light Fiber 40 Optical fiber 41 Bare optical fiber 42 Primary material coating layer 43 Secondary material coating layer

Claims (6)

An optical fiber manufacturing method in which two layers of ultraviolet curable resin coating are applied on an optical fiber at a drawing speed of 1000 m / min or more,
Half type that removes volatiles generated during curing by UV irradiation before applying the second layer coating layer device after applying and curing the first layer and curing by UV irradiation The trap gate of
A fiber entrance hole through which the optical fiber coated with the first layer is formed in the center of the trap gate is formed in parallel to the traveling direction of the optical fiber,
After washing to remove the volatiles deposited remove the trap gate in the drawing of the optical fiber, an optical fiber manufacturing method characterized by Rukoto bovine continued drawing of the optical fiber is attached again . An optical fiber manufacturing method in which two layers of ultraviolet curable resin coating are applied on an optical fiber at a drawing speed of 1000 m / min or more,
After the first layer is applied and cured by UV irradiation, the second layer is applied and cured, and a trap gate is provided in front of the second layer coating layer device.
Those fiber entrance hole of the trap gate shape of the formed convex portion in cross section Ri flared der substantially convex, said fiber entrance hole is formed in parallel to the traveling direction of the optical fiber method of manufacturing an optical fiber, characterized in der Rukoto. In the inner dimensions of the fiber entrance hole narrow-mouthed portion of the trap gates, light as claimed in claim 1 or claim 2, characterized in that the first layer coating layer outside diameter of + 0.05 to + 0.5 mm Fiber manufacturing method. An optical fiber manufacturing apparatus for applying two layers of UV curable resin coating on an optical fiber,
After the first layer is applied and cured by ultraviolet irradiation, a trap gate for removing volatiles generated at the time of curing by the ultraviolet irradiation is provided in front of the second layer coating layer device before applying and curing the second layer. Provided,
The trap gates, Ri Oh again attached is half type of removal during drawing of the optical fiber, fiber entrance hole through which an optical fiber coated with the first layer in the center with respect to the traveling direction of the optical fiber An optical fiber manufacturing apparatus characterized by being formed in parallel . An optical fiber manufacturing apparatus for applying two layers of UV curable resin coating on an optical fiber,
After the first layer is applied and cured by UV irradiation, the second layer is applied and cured, and a trap gate is provided in front of the second layer coating layer device.
And wherein the cross-section fiber entrance hole of the trap gate is formed has a divergent shape convex portion of the substantially convex, said fiber entrance hole is formed in parallel to the traveling direction of the optical fiber Optical fiber manufacturing equipment. 6. The light according to claim 4 , wherein an inner dimension of the fiber entrance hole of the trap gate is +0.05 to +0.5 mm of an outer diameter of the first coating layer at a narrow opening. Fiber manufacturing equipment.

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