JP2005189510A - Manufacturing method for covered wire body and ultraviolet irradiation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a covered wire body continuously for a long time while suppressing the clouding of a transparent tube and to provide an ultraviolet irradiation apparatus used for the manufacture. <P>SOLUTION: The covered wire body is manufactured in such a way that a wire body 40 is coated with resin, the wire body coated with the resin is allowed to pass through the inside of a transparent tube 61 which is disposed in the ultraviolet irradiation apparatus 60 and has a light translucent property for ultraviolet rays, at the same time, the resin is irradiated with the ultraviolet rays from an ultraviolet ray source 62 in the ultraviolet irradiation apparatus and the resin is cured. Wherein, when the resin is irradiated with the ultraviolet rays and is cured, the temperature of the transparent tube is made to be 200°C or more. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a coated filament having a filament coated with a resin, and an ultraviolet irradiation apparatus used in the production method.

  An optical fiber is manufactured by drawing an optical fiber preform to form a linear body, and then coating the surface of the linear body with a resin. This is to prevent the surface of the striated body from being scratched and broken. The coating of the striatum is carried out as follows.

  First, an ultraviolet curable resin is applied to the surface of the striatum, and is passed through a transparent tube disposed in the ultraviolet irradiation device. While the linear body to which the resin is applied passes through the transparent tube, the resin is cured by irradiating the resin with ultraviolet rays to form a coated linear body.

  In the process of curing the resin applied to the striatum, some components of the resin are volatilized by the reaction heat generated when the resin is cured and the heat generated by absorption of the irradiated light energy, and the inner surface of the transparent tube Adhere to. The resin component adhering to the inner surface of the transparent tube is altered by ultraviolet irradiation, and the transparent tube becomes cloudy. Thereby, the irradiation amount of the ultraviolet-ray to resin is reduced. When the irradiation amount of ultraviolet rays decreases, the resin may not be cured sufficiently.

  In order to prevent the uncured resin from being fogged, for example, Patent Document 1 discloses the following technique.

  In the light irradiation apparatus described in Patent Document 1, multiple quartz tubes are used. Here, a case where the quartz tube is provided in a double manner will be described as an example.

  A second quartz tube is disposed inside the first quartz tube. Then, the linear body to which the resin is applied passes through the second quartz tube. Since the quartz tube is doubled, the reaction heat generated when the resin is cured is not easily emitted from the second quartz tube. Therefore, the temperature of the second quartz tube is increased.

Due to this rise in temperature, the temperature of the second quartz tube is higher than the temperature of the first quartz tube. Further, in the step of curing the resin, an inert gas is allowed to flow in the second quartz tube. Therefore, the volatile component is easily discharged from the inside of the second quartz tube, and fogging is difficult to occur.
JP-A-4-224141

  However, when the running speed of the striate coated with the resin increases and the amount of the resin that passes through the transparent tube per unit time increases, the amount of the component that volatilizes from the resin also increases. In this case, according to the technique described in Patent Document 1, some components of the resin volatilized from the resin cannot be completely discharged from the second quartz tube, and fogging easily occurs. Therefore, it is difficult to produce a coated filament continuously for a long time.

  This invention is made | formed in view of the said situation, The objective is used for the method which can manufacture a coated filament | striate body continuously for a long time, suppressing the cloudiness of a transparent tube, and its manufacture. It is providing the ultraviolet irradiation device.

  Normally, organic substances are vaporized at the boiling point when heated. However, a polymer such as a resin covering an optical fiber does not have a boiling point and is chemically decomposed before being vaporized. The polymer is decomposed into water and carbon dioxide through a chemical decomposition process of oxidation and combustion at high temperatures in the air.

  By the way, even in an inert gas (for example, nitrogen or the like) in which no air exists, the polymer is broken at a high temperature by a portion having a weak molecular bond by thermal energy and decomposed into a low molecular component.

  These are a mixture of components having various boiling points depending on the molecular weight, but have a lower boiling point than the original organic substance and liquefy. Furthermore, some components are gasified and volatilized. Under sufficiently high temperature conditions, the components once in a liquid state are further decomposed, and all the components are successively reduced in molecular weight due to molecular cleavage, and are vaporized as gas.

  The inventors of the present invention have focused on the fact that the deposit on the inner surface of the transparent tube that causes the transparent tube to become cloudy is a black liquid. Then, the present inventors have found that the deposits are tarized after the volatile components from the resin adhere to the inner surface of the transparent tube having a relatively low temperature, solidify and solidify. Furthermore, the present inventors have found that, by sufficiently heating the transparent tube, the deposit can be gasified and volatilized from the inner surface of the transparent tube to be removed. The present invention has been made based on such knowledge.

  In order to solve the above-mentioned problems, a method for producing a coated filament according to the present invention comprises applying a resin to the filament, and providing the resin in a transparent tube that is provided in an ultraviolet irradiation device and is transparent to ultraviolet rays. Is applied to the resin, and the resin is cured by irradiating the resin with ultraviolet rays from an ultraviolet light source in the ultraviolet irradiation device, and the temperature of the transparent tube is set. It is characterized by being 200 ° C. or higher.

  In this case, the temperature of the transparent tube is 200 ° C. or higher in the method for producing a coated filament. Thereby, it is possible to suppress the occurrence of fogging in the transparent tube, and it is possible to manufacture the coated filaments while eliminating the generated fogging.

  Moreover, in the manufacturing method of the covered filament | striate which concerns on this invention, it is preferable that the temperature of a transparent tube shall be 400 degreeC or more. In this case, since the temperature of the transparent tube is 400 ° C. or higher, the inner surface of the transparent tube is not easily fogged, and the generated fog is easily eliminated.

  Furthermore, in the method for producing a coated filament according to the present invention, it is desirable that the oxygen concentration in the transparent tube be 5% or less. If the oxygen concentration is higher than 5%, the curing of the resin is inhibited. When the oxygen concentration is 5% or less, the resin can be sufficiently cured while promoting the decomposition of the cloudy component.

  Moreover, the ultraviolet irradiation device according to the present invention is applied to a transparent tube for transmitting a linear body that is transparent to ultraviolet rays and coated with a resin, and a linear body that passes through the transparent tube. It is characterized by comprising an ultraviolet light source that outputs ultraviolet rays to irradiate the resin, and heating means for heating the transparent tube to 200 ° C. or higher.

  In this case, ultraviolet rays are output from the ultraviolet light source when the linear body coated with the resin passes through the transparent tube. Then, the resin is cured by the ultraviolet rays output from the ultraviolet light source. Thereby, the covered filament | striate body which is a filament | striate body coat | covered with the hardened resin is formed. Further, since the transparent tube is heated to 200 ° C. or higher by the heating means, it is difficult for fogging to occur in the transparent tube, and the generated fog can be eliminated.

  Furthermore, in the ultraviolet irradiation apparatus according to the present invention, it is preferable that the heating means heats the transparent tube to 400 ° C. or higher. In this case, since the transparent tube is heated to 400 ° C. or higher by the heating means, the occurrence of fogging of the transparent tube is further suppressed.

  Moreover, in the ultraviolet irradiation device according to the present invention, it is desirable to include an oxygen concentration adjusting means for adjusting the oxygen concentration in the transparent tube. In this case, since the oxygen concentration in the transparent tube is adjusted by the oxygen concentration adjusting means, the resin can be sufficiently cured while promoting the decomposition of the cloudy component.

  It is possible to provide a method of producing a coated filament continuously for a long time while suppressing fogging of a transparent tube, and an ultraviolet irradiation device used for the production.

  In the following, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

  FIG. 1 is a diagram for explaining a method for producing a coated filament according to the present embodiment.

  The covered filament 10 is manufactured as follows. First, the optical fiber preform 20 mainly composed of quartz glass is set in the drawing furnace 30. One end of the optical fiber preform 20 is heated and melted by a heater 31 included in the drawing furnace 30, and the optical fiber preform 20 is drawn.

  The linear body 40 formed by drawing the optical fiber preform 20 includes an applicator 50 provided downstream of the drawing furnace 30 in the traveling direction of the linear body 40 (the direction of arrow A in FIG. 1). pass. The applicator 50 stores a liquid UV curable resin. Therefore, when the filament 40 passes through the applicator 50, an ultraviolet curable resin is applied to the outer periphery of the filament 40. Usually, two layers of resin are applied.

  The linear body 40 to which the resin is applied passes through an ultraviolet irradiation device 60 provided downstream of the applicator 50 in the traveling direction of the linear body 40. The ultraviolet irradiation device 60 irradiates the resin applied to the surface of the filament 40 with ultraviolet rays to cure the resin, thereby forming the coated filament 10.

  The coated filament 10 formed by passing through the ultraviolet irradiation device 60 is wound around the winding drum 72 through the guide roller 70 and the take-up means 71. The take-up means 71 is composed of a belt 71a and a roller 71b, and feeds the coated filament 10 to the take-up drum 72 by the rotation of the belt 71a and the rotation of the roller 71b. The belt 71 a and the roller 71 b of the take-up means 71 and the winding drum 72 are electrically connected to the control device 80, and the number of rotations is controlled by the control device 80. Thereby, the linear speed which is the running speed of the linear body 40 is controlled.

  An ultraviolet irradiation device 60 that cures a resin by irradiating ultraviolet rays will be described. The ultraviolet irradiation device 60 includes a transparent tube 61 for allowing the linear body 40 coated with a resin to pass therethrough, an ultraviolet light source 62, a reflecting mirror 63, and a heating means 64.

  The reflecting mirror 63 is provided around the transparent tube 61 and the ultraviolet light source 62. When the ultraviolet irradiation device 60 is cut along a plane perpendicular to the traveling direction of the filament 40, the shape of the reflecting mirror 63 is an ellipse. And the linear body 40 and the ultraviolet light source 62 are each arrange | positioned in the position of the two focal points of the ellipse.

  The transparent tube 61 is not particularly limited as long as it has translucency with respect to ultraviolet rays. For example, the transparent tube 61 is a quartz tube. The ultraviolet light source 62 outputs ultraviolet light that irradiates the resin applied to the linear body 40 that passes through the transparent tube 61. The ultraviolet light source 62 is, for example, a metal halide lamp.

  The heating means 64 heats the transparent tube 61 to 200 ° C. or higher, preferably 400 ° C. or higher. An example of the heating means 64 is a tape heater. As shown in FIG. 1, the heating means 64 is preferably provided at an end portion on the inlet side and an end portion on the outlet side of the filament 40 in the transparent tube 61. This is because it is possible to suppress a decrease in the amount of ultraviolet irradiation to the resin by the heating means 64. In addition, when the heating means 64 is a tape heater, it should just wrap around the said both ends of the transparent tube 61, respectively.

  In the ultraviolet irradiation device 60, the linear body 40 coated with resin passes through the transparent tube 61. When the filament 40 passes through the transparent tube 61, ultraviolet rays are output from the ultraviolet light source 62. The ultraviolet light output from the ultraviolet light source 62 is directly or after being reflected by the reflecting mirror 63, passes through the transparent tube 61, and is applied to the resin applied to the linear body 40 that passes through the transparent tube 61. The Thereby, resin is hardened and the coated filament 10 is obtained.

  In the manufacturing method of the coated filament of this embodiment, when hardening resin, the transparent tube 61 is heated with the heating means 64, and the temperature of the transparent tube 61 shall be 200 degreeC or more, Preferably it is 400 degreeC or more. By setting the temperature of the heating means 64 within the above range, the temperature of the transparent tube 61 also falls within the above range. The temperature of the transparent tube 61 is measured by a radiation thermometer 65, for example. And according to the measurement result, the heating means 64 may be controlled to bring the temperature of the transparent tube 61 into the above range.

  By the way, in the step of curing the resin applied to the striate body 40, some components of the resin are volatilized due to reaction heat generated when the resin is cured and heat generated by absorption of irradiated light energy. A part of the volatilized resin component adheres to the inner surface of the transparent tube 61. The resin component adhering to the inner surface of the transparent tube 61 is altered by ultraviolet irradiation. As a result, the transparent tube 61 becomes cloudy, and the amount of ultraviolet rays applied to the resin decreases. When the irradiation amount of ultraviolet rays decreases, the resin may not be cured sufficiently.

  On the other hand, the present inventors confirmed that the deposit | attachment adhering to the transparent tube 61 is decomposed | disassembled in the said temperature range. FIG. 2 is a graph showing an analysis result of a deposit attached to the transparent tube 61 by a gas chromatograph mass spectrometer.

  The sample analyzed by the gas chromatograph mass spectrometer was obtained by wiping the deposits on the inner surface of the transparent tube 61 used when manufacturing the coated filament 10 with quartz wool containing ethanol. A quartz tube was used as the transparent tube 61. The sample was heated from 50 ° C. to 800 ° C. in an oxygen-free atmosphere with a pyrolyzer (Double Shot Pyrolyzer PY-2020D manufactured by Frontier Labs). The heating rate was 30 ° C./min. Then, components generated from the sample were introduced into a gas chromatograph mass spectrometer and measured.

図２において、横軸は昇温開始からの経過時間（分）を示しており、縦軸は発生成分量を示している。なお、昇温速度が一定であるため、横軸は試料の温度にも相当する。 The conditions for gas chromatograph mass spectrometry are shown in Table 1.

In FIG. 2, the horizontal axis indicates the elapsed time (minutes) from the start of temperature rise, and the vertical axis indicates the amount of generated components. Since the rate of temperature increase is constant, the horizontal axis corresponds to the temperature of the sample.

  The gas generated at 200 ° C. or lower is caused by ethanol that has soaked into quartz wool for wiping the sample from the inner surface of the quartz tube. FIG. 2 shows that when the sample is heated to 200 ° C., gas starts to be generated from the sample. Gas generation once decreases around 230 ° C., but gas starts to be generated again from around 400 ° C. And it was less than the amount of components generated at 200 ° C. around 710 ° C. That is, it can be seen that the sample was almost thermally decomposed at 710 ° C.

  In the gas chromatograph mass spectrometer when no sample was set, the total ion chromatogram obtained under the same conditions had a generated component amount of 20000 or less from room temperature to around 710 ° C. Therefore, the total ion chromatogram of the deposit shown in FIG. 2 is attributed to the sample.

  As described above, the sample is a deposit attached to the inner surface of the transparent tube 61, that is, a cloudy component causing cloudiness. Therefore, from the measurement result of FIG. 2, by heating the transparent tube 61 to 200 ° C. or higher, some components of the deposits adhering to the inner surface of the transparent tube 61 are separated from the inner surface of the transparent tube 61 as gas. As the temperature increases, the deposits are thermally decomposed.

  Therefore, in the production of the coated filament of this embodiment in which the temperature of the transparent tube 61 is set to 200 ° C. or higher, some components of the resin volatilized from the resin are difficult to adhere to the transparent tube 61 and the occurrence of cloudiness is suppressed. In addition, it is possible to eliminate fogging.

  Further, as described above, in FIG. 2, the amount of gas generated increases again from the temperature of the sample near 400 ° C. This indicates that the sample, that is, the adhering material adhering to the inner surface of the transparent tube 61 contains a component that starts to gasify at a temperature higher than 400 ° C. Therefore, from the viewpoint of decomposing the cloudy component, it is desirable that the transparent tube 61 be 400 ° C. or higher.

  Furthermore, from the viewpoint of decomposing cloudy components, the temperature is preferably high, but when the temperature of the transparent tube 61 is high, the life of other devices such as the ultraviolet light source 62 tends to be shortened. On the other hand, as understood from FIG. 2, when the temperature of the transparent tube 61 is heated to 700 ° C., the cloudy component can be gasified and volatilized. Therefore, the temperature of the transparent tube 61 is preferably 200 ° C. or higher and 700 ° C. or lower. Thereby, the covered filament | striate body 10 can be manufactured, suppressing the damage to another apparatus, suppressing generation | occurrence | production of cloudiness and eliminating cloudiness.

  Moreover, since the temperature of the transparent tube 61 is preferably 400 ° C. or higher as described above, 400 ° C. or higher and 700 ° C. or lower is more preferable.

  By the way, from the viewpoint of gasifying and volatilizing the deposits in the transparent tube 61, a higher oxygen concentration is better. However, when the oxygen concentration is high, curing of the resin is inhibited. If the oxygen concentration is 5% or less, the resin can be sufficiently cured while promoting the decomposition of the cloudy component. Therefore, the oxygen concentration in the transparent tube 61 is preferably 5% or less. Moreover, it is preferable for the oxygen concentration to be 2% or less because inhibition of curing of the ultraviolet curable resin used for coating the optical fiber can be suppressed.

  There are various methods for adjusting the oxygen concentration. For example, the oxygen concentration may be adjusted as follows. A gas introduction pipe 90 is connected to the transparent pipe 61 shown in FIG. A gas supply means 91 for supplying a mixed gas containing oxygen and an inert gas (for example, nitrogen) is connected to the end of the gas introduction pipe 90 opposite to the transparent pipe 61. A flow rate regulator 92 is provided in the gas introduction pipe 90. The flow rate controller 92 adjusts the flow rate of the mixed gas supplied from the gas supply unit 91 through the gas introduction pipe 90 to the transparent pipe 61. Examples of the flow rate regulator 92 include an adjustment valve and a mass flow controller.

  Further, in the transparent pipe 61, a gas discharge pipe 93 is connected to a part different from the part to which the gas introduction pipe 90 is connected. A gas discharge means 94 for discharging the gas in the transparent tube 61 is connected to the end of the gas discharge tube 93 opposite to the transparent tube 61. The gas discharge pipe 93 is provided with a flow rate regulator 95 similar to the flow rate regulator 92. The flow rate regulator 95 adjusts the flow rate of the gas in the transparent tube 61 that is discharged through the gas discharge pipe 93 by the gas discharge means 94.

  A pipe 97 whose one end is connected to the oximeter 96 is connected to the downstream side of the flow controller 95, that is, to the gas discharge pipe 93 between the flow controller 95 and the gas discharge means 94. . The oxygen concentration meter 96 may be located upstream of the flow rate controller 95. Further, a filter 98 is provided upstream of the flow rate regulator 95 in the gas discharge pipe 93. This is to remove some components of the volatilized resin from the resin in the transparent tube 61 and prevent damage to the flow controller 95 and the oxygen concentration meter 96.

  Then, the oxygen concentration of the gas in the transparent tube 61 discharged through the gas discharge tube 93 is measured by the oxygen concentration meter 96. In accordance with the measurement result, the flow rate controller 92 adjusts the flow rate of the mixed gas supplied to the transparent tube 61 through the gas introduction tube 90 so that the oxygen concentration in the transparent tube 61 is 5% or less. At that time, the amount of gas discharged from the transparent tube 61 is also adjusted by the flow rate regulator 95. Thereby, the oxygen concentration in the transparent tube 61 is adjusted to the said range.

  As can be understood from the above description, the gas introduction pipe 90, the gas supply means 91, the flow rate regulator 92, the gas discharge pipe 93, the gas discharge means 94, the flow rate regulator 95, and the oxygen concentration meter 96 are oxygen in the transparent pipe 61. It functions as an oxygen concentration adjusting means for adjusting the concentration.

  As described above, in the method for manufacturing a coated filament of this embodiment, the temperature of the transparent tube 61 is 200 ° C. or higher, and therefore, the occurrence of fogging on the inner surface of the transparent tube 61 is suppressed. Further, even if fogging occurs, the fogging can be eliminated by raising the temperature of the transparent tube 61 within the above range. Thereby, when manufacturing the elongate covering linear body 10, even when the running speed of the linear body 40 is raised, it is suppressed that hardening of resin becomes inadequate by fogging of the transparent tube 61. FIG. . Therefore, the elongate covered filament | striate body 10 can be manufactured efficiently.

  As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to the said embodiment. For example, the heating means 64 is only required to heat the transparent tube to 200 ° C. or higher, and can be heated with an infrared heater. Further, the position of the heating means 64 is not particularly limited as long as a decrease in the amount of ultraviolet irradiation to the resin by the heating means 64 is suppressed and the transparent tube 61 can be heated.

  Moreover, in the said embodiment, although the filament 40 is drawn and formed from an optical fiber preform | base_material, the optical fiber strand which is the covering filament 10 is manufactured, An optical fiber strand is used as a filament. Also good. In this case, an optical fiber core wire is manufactured. Moreover, although the ultraviolet irradiation apparatus 60 is provided with the reflective mirror 63, it is not necessarily provided with the reflective mirror, and it is very good.

It is a figure explaining the manufacturing method of a covered filament. It is a graph which shows the analysis result by the gas chromatograph mass spectrometer of the deposit | attachment adhering to the transparent tube.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Coated striate, 40 ... Striate, 60 ... Ultraviolet irradiation apparatus, 61 ... Transparent tube, 62 ... Ultraviolet light source, 64 ... Heating means, 90 ... Gas introduction pipe, 91 ... Gas supply means, 92 ... Flow control 93, gas discharge pipe, 94, gas discharge means, 95, flow controller, 96, oxygen concentration meter.

Claims (6)

A resin is applied to the striatum, and the striate coated with the resin is passed through a transparent tube that is provided in the ultraviolet irradiating device and is transparent to ultraviolet rays. A method of producing a coated filament by irradiating the resin with ultraviolet rays from a light source to cure the resin,
The method for producing a coated filament, wherein the temperature of the transparent tube is 200 ° C or higher.   The method for producing a coated filament according to claim 1, wherein the temperature of the transparent tube is set to 400 ° C or higher.   The method for producing a coated filament according to claim 1 or 2, wherein the oxygen concentration in the transparent tube is 5% or less. A transparent tube that is transparent to ultraviolet rays and has a linear body coated with resin;
An ultraviolet light source that outputs ultraviolet rays applied to the resin applied to the striatum passing through the transparent tube;
An ultraviolet irradiation apparatus comprising heating means for heating the transparent tube to 200 ° C. or higher.   The ultraviolet irradiation apparatus according to claim 4, wherein the heating unit heats the transparent tube to 400 ° C. or more.   6. The ultraviolet irradiation apparatus according to claim 4, further comprising oxygen concentration adjusting means for adjusting the oxygen concentration in the transparent tube.

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