JP2584468B2 - Method of coating wire with resin and irradiation device used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a method for coating a wire rod which cures an energy ray-curable resin applied to the surface of a wire rod traveling at a high speed by irradiation with energy rays, and uses the method. The present invention relates to an irradiation device.

<Prior Art> Optical fibers used for optical communication are not limited to optical glass fibers and quartz glass fibers, and it is preferable that a plastic coating be applied to the outer periphery of each of the fibers immediately after fiberization. This is to prevent the fiber strength from being degraded due to scratches on the fiber surface caused by conversion into a fiber or crack growth due to exposure to the air in the state of a bare fiber.
As such a plastic layer, generally, an energy ray-curable resin such as a thermosetting silicone resin, an ultraviolet-curable resin (hereinafter referred to as a “UV resin”), a radiation-curable resin, and the like is used. The demand for resin-coated fibers is increasing.

A method for manufacturing such a UV resin-coated optical fiber will be described with reference to FIG. As shown in the figure, a preform 02 supplied into a heating furnace 01 by a preform supply device (not shown) is melted by a heater 03 in the heating furnace 01,
The optical fiber 04 is drawn. The drawn optical fiber 04 passes through a cooling cylinder 05 to form a coating die.
06, for example, a UV resin is applied, and then passes through the inside of the ultraviolet irradiation device 07 to be irradiated with ultraviolet light,
The primary coating of the optical fiber is made of resin. The primary coated optical fiber 04 'is further
A secondary coating with a UV resin or the like is applied to form an optical fiber, which is wound around a winding device (not shown).

Here, an ultraviolet irradiation device used for the primary coating is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-191038, and its outline is shown in FIG. As shown in the figure, an ultraviolet irradiation device (hereinafter referred to as “UV device”) 07 includes a UV lamp 09 for generating ultraviolet light inside an apparatus main body 08, and a mirror 010 for condensing the ultraviolet light on an optical fiber. And a cylindrical tube 011 through which an optical fiber 04 ′ coated with UV resin is inserted at the position where the ultraviolet rays are condensed. Further, an introduction pipe 012 for introducing a purge gas such as N ₂ gas is connected to a lower end of the tube material 011 to remove oxygen that inhibits a radical reaction initiated by ultraviolet rays. Along with this, tubing 011
A shutter 013 is provided at the upper end of the shutter to reduce the outflow of the purge gas.

<Problems to be Solved by the Invention> However, in the conventional UV device 07, when irradiating ultraviolet rays to cure the UV resin, a large amount of ultraviolet rays and accompanying infrared rays are irradiated, so that the UV resin Part thereof is volatilized, and deposits adhere to the inner surface of the tube 011. This deposit is derived from the UV resin and absorbs ultraviolet light.As a result, the transmittance of the tube material 011 is reduced, and a sufficient amount of light for curing the UV resin applied to the optical fiber is obtained. There is a problem that it takes time.

In view of the circumstances described above, an object of the present invention is to provide a method of coating a wire with a resin capable of stably curing a curable resin applied to a running wire over a long period of time, and an irradiation apparatus used therefor. I do.

<Means for Solving the Problems> The present inventors have found that most of the deposits adhering to the inner surface of the above-mentioned tube material are generated in a low linear velocity state at the start of drawing and when a large amount of energy rays are irradiated. It was found that. Based on such knowledge, the present inventors carry out a method for efficiently coating a wire with a resin by an energy beam without stopping the wire traveling at high speed and without being affected by the attached matter, and implement the method. The invention of the energy beam irradiation device was completed.

The configuration of the method for coating a wire with a resin according to the present invention, when coating and curing a cured resin by irradiating an outer peripheral surface of a traveling wire with an energy ray through a pipe, from a state of a low linear velocity at the start of the travel. Until the state of the constant linear velocity is reached, the energy ray is radiated through a tube that can move in the traveling wire direction, and then the tube is moved in any of the traveling directions of the wire, until the constant linear velocity is reached. The irradiation part of the tube material located within the irradiation range is moved out of the irradiation range.

Further, the configuration of the first irradiation device of the present invention includes a pipe provided so that a traveling wire is inserted therethrough, and an irradiation source for irradiating the wire with an energy beam through the pipe, and the traveling wire is provided. An energy beam irradiation device for curing the cured resin applied to the outer peripheral surface of the tube by irradiating the energy beam with the energy beam, wherein the tube material is movable in the axial direction, while the second irradiation of the present invention is performed. The configuration of the device has a tube provided so that the traveling wire is inserted therethrough, and an irradiation source for irradiating the wire with an energy ray through the tube, and the curable material applied to the outer peripheral surface of the traveling wire is provided. In an energy beam irradiation apparatus for curing a resin by irradiating the energy beam, the tube material is at least a double tube, and at least the innermost tube moves out of any irradiation range in the drawing direction. Characterized in that it is a capability.

<Operation> During the time from the low linear velocity state at the time of drawing start to the state of constant linear velocity, the deposits volatilized from the energy ray-curable resin due to the influence of the energy ray irradiation can be removed from a part of the pipe material or the inside of the multi-tube. After adhering to the pipe and reaching the above constant linear velocity,
The tube material or the inner tube is moved in any of the insertion directions of the optical fiber and out of the energy ray irradiation range, and the energy beam is irradiated through the tube material having no attached matter to cure the energy ray curable resin.

<Embodiment> Hereinafter, a preferred embodiment for carrying out the method of the present invention will be described.

FIG. 1 shows an ultraviolet irradiation apparatus according to a first embodiment for carrying out the method of the present invention. As shown in FIG. 1, in an ultraviolet irradiation device (hereinafter, referred to as “UV device”) 1A, a tube material 3 through which an optical fiber 2 is inserted penetrates vertically above and below a device main body 4 and is movable in a vertical direction. . The length of the tube 3 in the axial direction is at least about three times the length of the device body 4 in the vertical direction, and the state before the movement is the upper end of the device body 4 and the upper end of the tube 3. The lower end of the tubular member 3 is provided substantially below the main body at the same position. In addition, the pipe material 3
A gas introduction pipe 5 for filling the inside of the pipe material 3 with an inert gas is provided at the lower end portion of the tube 3 as in the related art. Further, a shutter 6 is provided at the upper end to prevent outflow of gas.
An ultraviolet lamp (hereinafter referred to as “lamp”) 7 is provided inside the main body 4 as in the conventional case, and ultraviolet light emitted from the ultraviolet lamp 7 is collected by a mirror 8 provided around the lamp 7. Thus, the UV resin applied to the optical fiber 2 passing through the tube 3 is cured.

In such a UV device 1A, after reaching a constant linear velocity state from a low linear velocity state at the time of tapping at the start of drawing an optical fiber, the movable tube member 3 is located in the apparatus main body 4. Is moved upward (Z direction in the figure) until it is located outside the apparatus main body 4, so that the inner surface of the tube material located within the irradiation range is kept free of dirt.

In addition, when drawing continuously over a long period of time, the linear movement reaches a constant linear velocity from a low linear velocity and performs the above-described large movement, and thereafter, according to the drawing time and the degree of contamination of the attached matter on the inner surface of the pipe material. If you gradually move the tube 3 upward,
The inner surface of the illuminated area of the tube can be maintained for a longer period of time without contamination.

In this embodiment, as described above, the pipe 3
After a certain period of time, the contaminated portion in the tube was moved to the outside of the apparatus, and then moved gradually, so that the length of the tube 3 was reduced to about the length of the apparatus body 4 in the vertical direction. I needed about three times. However, after moving a portion of the dirty irradiation range out of the range after a certain period of time,
If the tube is not gradually moved, the length may be about twice as long, and even if the length is not more than twice, the irradiation dose is improved by the movement of the tube.

FIG. 2 shows an irradiation apparatus according to a second embodiment for implementing the method of the present invention. In this embodiment, instead of the movable tube of the first embodiment, an inner tube which can be moved outside the apparatus main body and held in that state is provided inside the fixed tube described in the conventional example. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

As shown in the figure, in the ultraviolet irradiation apparatus 1B of the present embodiment, an optical fiber is inserted inside the tube material 3 penetrating the upper and lower sides of the apparatus main body 4 and is movable upward to move outside the main body 4. An inner tube 10 that can be held is provided. A shutter 11 is provided at the upper end of the inner tube 10 in order to prevent the purge gas filled in the tube from flowing out. The inner cylindrical tube 10 has an upper end flange portion 10a in contact with an upper opening 3a of the tube 3 and a distal end extending to near the lower end of the tube 3. A gas inlet pipe 5 is provided at the lower end of the tube 3 to fill the inside of the tube 3 with an inert gas, as in the first embodiment. The upper end of the tube 3 is closed by the flange portion 10a of the inner tube 10. However, when the inner tube 10 is moved above the upper end of the tube 3 as described above, Tubing opening
3a is closed again by a shutter (not shown) to prevent outflow of gas.

In such a UV device 1B, from the low linear velocity state to a constant linear velocity at the start of drawing the optical fiber,
If the deposit from the UV resin is adhered to the inner tube 10 which can be extracted, and then only the inner tube is extracted upward, ultraviolet rays are irradiated through the clean tube 3. In this embodiment, when a long-time use is performed, it is unavoidable that a very small amount of adhered substance is adhered, but there is no problem at all if a short-time drawing is performed.

In this embodiment, the inner tube is provided inside the tube 3.
Although only one 10 was provided, if this is provided double or triple,
UV resin curing can be performed for a long time. That is, it is possible to always irradiate through a new tube material and the inner tube by moving the dirty inner tube from the inside one by one to the outside of the ultraviolet irradiation range with the passage of time.

<Test Example> Next, a test example showing the effect of the present invention will be described below.

In this test example, the relationship between the linear velocity and the amount of attached matter was tested using the ultraviolet irradiation apparatus 1A disclosed in Example 1 under the conditions shown in Table 1.

Under the conditions shown in Table 1, when each set speed is reached and a stable state is reached, a new inner surface of the tube is
Ultraviolet rays were irradiated for one hour to cure the UV resin applied to the running optical fiber, and to attach volatiles generated from the resin at that time.

At this time, the attached amount of the attached matter in the tube was measured. Similarly, a linear velocity of 10 to 100 m / min was performed. At this time, the pipe member 3 was slid upward each time the speed was changed so that a new inner surface was always located in the apparatus main body 4 at each speed. After the test, the amount of deposits in the tube 3 per hour at each speed was measured.

 The results are shown in Table 2 and FIG.

As shown in Table 2 and FIG. 3, it was found that when the linear velocity was a low linear velocity of 20 m / min or less, the amount of adhesion on the inner surface of the tube was overwhelmingly large.

FIG. 4 shows the relationship between the linear speed and the time from when the actual drawing of the optical fiber is started to when the drawing is performed at a constant linear speed and when the non-defective product is picked up. As shown in the figure, the time from the tapping to reaching the linear speed (100 m / min) for non-defective product collection was about 0.9 hours, which was within 1 hour.

From these test results, deposits adhering to volatilize to the tube member without being cured UV resin by ultraviolet irradiation, yarn end finding during about 200 [mu] g / cm ^2, can be estimated to be about 33 .mu.g / cm ² at the time of non-defective-up, yarn end finding during The amount of the attached matter was overwhelmingly large.

Next, using the UV device 1A of the first embodiment, after a lapse of the tapping time (approximately 0.9 hr), the irradiated portion of the tube material irradiated with the ultraviolet rays in the device main body 4 is moved above the device main body 4. It was out of the irradiation range of ultraviolet rays, and thereafter, the tube material 3 was gradually moved with the passage of time and applied to the actual optical fiber
The UV resin was cured. The gel fraction (curing rate) with respect to the time at this time was measured.

The gel fraction was measured by immersing the optical fiber coating layer after ultraviolet irradiation in methyl ethyl ketone at about 60 ° C. and comparing the weight of the coating layer before and after immersion.

Similarly, using the UV device 1B of Example 2, after the elapse of the tapping, the inner tube 10 was pulled upward to cure the UV resin applied to the optical fiber, and then the gel fraction was measured.

For comparison, the UV resin applied to the optical fiber was similarly cured using a conventional apparatus, and then the gel fraction was measured.

The results of the above gel fraction measurement are shown in FIGS.
It is shown in (c).

As shown in the figure, in Examples 1 and 2, the gel fraction largely returned to the original value around 0.9 hr. This change corresponds to the case where the pipe material is largely moved in the first embodiment and the case where the inner tube 10 is pulled out in the second embodiment. Thereafter, no fluctuation is observed in the first embodiment. In addition, the second embodiment is the same as the first embodiment, and has a long time (4 hours).
After the elapse of the time, the gel fraction gradually decreases and does not hinder the curing.

Further, in the conventional example, the gel fraction is significantly reduced between 0.5 hr and 1.0 hr, but this is because the irradiation light intensity is attenuated due to the absorption of the adhered substance adhered to the inner peripheral surface of the tube, It is considered that the irradiation time was shortened due to the simultaneous increase in the linear velocity of the drawing, so that the total irradiation light amount was small and the cured state was low.

From the results described above, according to the method of the present invention, the adhered matter at the time of tapping is removed or moved after being adhered for a certain period of time to remove the adhered matter that hindered the ultraviolet absorption of the tube material. The irradiation amount of ultraviolet rays is substantially increased as compared with the case of performing ultraviolet irradiation. Thus, in the method of the present invention, even if the linear velocity of the optical fiber is increased, the irradiation amount of ultraviolet rays is large, so that the UV resin can be sufficiently cured. In the case of curing the UV resin of the optical fiber at a low linear velocity, if the tubing is slid according to the linear velocity and the amount of adhesion by using the apparatus 1A used in Example 1, the drawing is performed for a long time. Then, the UV resin can be cured.

<Effects of the Invention> As described in detail with the embodiments above, according to the present invention, the wire is decomposed by the energy beam irradiation from the low linear velocity state at the start of drawing to the constant linear velocity state. By moving the tube material or the inner tube to which the decomposition product is attached to outside the irradiation range, the influence of the attachment material is eliminated, and the ultraviolet irradiation at a constant linear velocity can be performed stably.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view of an essential part of an ultraviolet irradiation apparatus according to a first embodiment for carrying out the method of the present invention, FIG. 2 is a sectional view of an essential part of the ultraviolet irradiation apparatus according to the second embodiment, and FIG. FIG. 4 is a graph showing the relationship between the attached matter of the optical fiber and the linear velocity in the first embodiment, FIG. 4 is a graph showing the relationship between the linear velocity and time according to the apparatus of the first embodiment, and FIGS. (C) is a graph showing the relationship between the gel fraction of each resin cured by the apparatus of the second embodiment of the first embodiment and the conventional example and time, and FIG. 6 is a method for producing a UV resin-coated optical fiber. Conceptual diagram representing the seventh
The figure is a cutaway perspective view of a main part of a conventional ultraviolet irradiation device. In the drawings, 1A and 1B are ultraviolet irradiation devices, 2 is an optical fiber, 3 and 10 are tube materials, 4 is an apparatus main body, and 7 is an ultraviolet lamp.

Claims (3)

(57) [Claims] 1. When a hardening resin is coated and hardened by irradiating an outer peripheral surface of a running wire with an energy beam through a tube, from a state of a low linear velocity at the start of the running to a state of a constant linear speed. Irradiates an energy ray through a tube movable in the direction of the traveling wire, and then moves the tube in any direction of travel of the wire, and is located within the irradiation range until the constant linear velocity is reached. A method for coating a wire with a resin, the method comprising: moving an irradiated portion of a tube material out of an irradiation range. 2. A cured resin applied to an outer peripheral surface of a traveling wire having a tube provided so as to allow a traveling wire to pass therethrough, and an irradiation source for irradiating the wire with an energy beam through the tube. An energy beam irradiation device for curing the material by irradiating the energy beam with the energy beam, wherein the tube is movable in an axial direction. 3. A hardening material applied to an outer peripheral surface of a traveling wire having a tube provided so that a traveling wire is inserted therethrough, and an irradiation source for irradiating an energy beam to the wire through the tube. In an energy beam irradiation device for curing a resin by irradiating the energy beam, the tube material is at least a double tube or more, and at least the innermost tube can be moved out of any irradiation range in the drawing direction. An irradiation device characterized by the above-mentioned.