JPH01159079A - Die for coating - Google Patents

Abstract

PURPOSE:To prevent the formation of ununiform thickness of low-viscosity liquid resin applied on a wire rod by transferring and regulating the relative position of a first die and a second die provided with holes for passing the wire rod to the direction orthogonal to the travelling direction of the wire rod. CONSTITUTION:A first and second dies 121, 122 provided with holes for passing a wire rod 3 are provided and this wire rod 3 is simultaneously applied with low-viscosity liquid resin at two layers. The relative position of the die 121 and the die 122 is transferred and regulated to the direction orthogonal for the travelling direction of the wire rod 3 by an aligning means 130. As a result, the formation of ununiform thickness of low-viscosity liquid resin applied on the wire rod is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a coating gou for simultaneously applying two layers of low-viscosity resin to a running wire such as an optical fiber to be drawn.

<Prior Art> In optical fibers used for optical communications, it is said that it is preferable not only to optical glass fibers and quartz-based glass fibers, but also to immediately apply a plastic coating to the outer periphery of the optical fibers after forming them into fibers. This is to prevent the strength of the fiber from deteriorating due to scratches on the surface of the fiber that occur when the fiber is made into a fiber, or cracks that grow when the bare fiber is exposed to the air. Such a plastic layer is generally made of a reactive material such as a thermosetting silicone resin or an ultraviolet curable resin (hereinafter referred to as UV resin), which is a low viscosity solution that is cured by heat or ultraviolet rays to form a structure. Resin is used,
In recent years, demand for UV resin-coated fibers has been increasing.

On the other hand, in this optical fiber coating structure, if stress is applied from the side direction to the glass fiber that is the light guiding part, the transmission loss will increase, so a protective layer with a relatively high elastic modulus is provided on the outside and a protective layer is provided on the inside. It is common to have a two-layer structure in which a buffer layer with a relatively low elastic modulus is provided to support and disperse the force from the side (for example, Japanese Patent Laid-Open No. 60-25115
(See Publication No. 3).

Conventionally, when manufacturing such a two-layer optical fiber, a preform 1 is placed in a heating furnace 2 as shown in FIG.
For example, the bare fiber 3 obtained by drawing in
Two sets of coating die 10 and curing device 11 as shown in Japanese Patent No. 177931 were used. That is, the bare fiber 3 obtained by drawing the preform 1 in a heating furnace
was made into a double-layer coated fiber 4 by passing through two sets of coating dies 10 and a curing device 11.

Incidentally, in recent years, the demand for optical fibers has increased and the desire for price reduction has increased, so improving the productivity of optical fibers has become a major issue. It is known that when increasing the manufacturing speed of optical fiber, the problem with coating coating material is the temperature of the optical fiber during coating (A
ppl, Opt, 20 (23), 4023 (
(1981)). One possible way to lower the temperature of this optical fiber is to increase the distance that the bare fiber travels in the air. For this reason, in order to increase the running distance of the bare fiber in the air without increasing the overall length, the two sets of coating dies 10 described above are replaced with two-layer coating dies, and the coating dies 1fi y+... 1 le tithe! ”r 11
A better method would be to obtain the air cooling length for one set.

Therefore, conventionally, a two-layer coating die as shown in FIG. 4 has been used. As shown in the figure, the two-layer coating die 20 has holes 21 a, through which the bare fiber 3 passes, respectively.
It consists of a first die 21 and a second die 22 having 22 a and 23 a, and a point 23, and the first die 21
Inverted conical resin chambers 24 and 25 are defined between the point 23 and the first die 21 and the second die 22, respectively. That is, the point 23 is fitted to the upper side of the first die 21 and fixed with the point fixing screw 26 to define a first resin reservoir chamber 24, and the second die 22 is fitted to the upper side of the first die 21. 21 and fixed with the die fixing screw 27, the second resin reservoir chamber 25 is formed.
is defined.

Such a die has such a recombination function because it is necessary to disassemble and clean the inside when changing the resin or after using it for a long time. That is, if impurities, dust, etc. enter the die, or if resin remaining in the die deteriorates, the strength and other characteristics of the optical fiber may deteriorate if it is coated as is.

The first die 21 has these resin reservoir chambers 24 and 25.
First and second resin inlets 28,29 are formed which communicate with the resin inlets 28,29. The first die 21 and the second die 22 are each directly fixed to the holder wall.

<Problems to be Solved by the Invention> The total thickness of the coating layer of the optical fiber as described above is approximately 70 μm on one side, and the thickness of each of the first and second layers is several tens of μm or less. Therefore, the fiber clearance of the die is very small.

By the way, it is quite difficult to obtain an accuracy of several μm or less using current metal processing technology, and it is difficult to obtain an accuracy of 5 μm or less with cemented carbide or steel that is generally used as a die. Further, the gap for fitting the first and second dies 21 and 22 is required to be at least 10 μm or more, and even in the case of mechanical assembly, it is required to be several μm or more. Therefore, the holes 21a of the first die 21 and the second die 22.

The core of 22a is often misaligned due to processing accuracy and assembly accuracy.

If two layers were coated at the same time in such a state, there was a problem in that so-called scratches were created in which the axes of the negative layer and the second layer were misaligned.

SUMMARY OF THE INVENTION In view of these problems, an object of the present invention is to provide a two-layer coating die that does not cause uneven thickness.

Means for Solving the Problems> The structure of the double-layer coated die of the present invention that achieves the above object includes first and second dies having holes through which the wire passes, and the wire has a low viscosity. A coating die for simultaneously applying two layers of liquid resin, comprising alignment means for moving and adjusting the relative positions of the first die and the second die in a direction perpendicular to the running direction of the wire rod. It is characterized by

In conventional second coating, the first layer is applied by a resin flow in which the wire pulls the resin of the first layer, a so-called traction flow, and this traction flow causes the wire to self-align and die. moved towards the center. Then, when the wire passed through the first die enters the second die whose center is shifted by the processing precision or assembly precision, the self-aligning force (!&<
However, since this force is generated between the applied liquid first layer and the second layer of resin, it is weaker than the above-mentioned force, and often the thickness is uneven without alignment. Also, due to this self-aligning force,
The first layer, which was applied without uneven thickness, may instead have uneven thickness.

The present invention prevents such inconvenience with the above-described configuration, and adjusts the damage caused when the wire enters the second die from the first die.

Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the two-layer coating die of this example.

As shown in the figure, the two-layer coating die 120 of this embodiment has holes 121a and 122 through which the bare fiber 3 passes, respectively.
a, a first die 121 and a second die 1 having 123a
22 and a point 123, and an inverted conical resin reservoir 124 between the first die 121 and the point 123 and between the first die 121 and the second die 122, respectively.
125 is defined as in the conventional case, but the second die 122 is movable in the horizontal direction with respect to the first die 121. That is, on the lower side of the first die 121, there is a die holding portion 121 having a diameter larger than that of the second die 122.
b is formed, and after the second die 122 is accommodated in this goo holding portion 121b, it is supported by a die fixing screw 127 so as to be movable in the horizontal direction. Four thickness unevenness adjustment screws 130 are provided at equal intervals on the lower outer periphery of the first die 121 so that their tips protrude into the die holding part 121b. The horizontal position of the second die 122 can be adjusted. In this embodiment, a second die 122 is provided as an alignment means so as to be movable in the horizontal direction with respect to the first die 121, and a tip abutment is provided on the outer circumference of the second die on the outer circumference of the first die 121. A contact adjustment heel 130 is provided. In addition, in the figure, 126 points 122 to the first die 12.
It is a point fixing screw that fixes to 1, and also 128,
Reference numerals 129 indicate first and second resin inlets communicating with the resin reservoir chambers 124 and 125, respectively; The resin is transferred to the second resin reservoir chamber 12 from the second resin population 129.
It's set to fall into the 5th category.

In such a two-layer coating die, the bare fiber 3 that is drawn and runs from top to bottom in the figure is inserted through the hole 122a at the point 122, enters the first resin reservoir 124, and is coated with the first layer. , then enters the second resin reservoir chamber 125 through the hole 121a, and enters the hole 123a with the second layer coated.
It comes out more. At this time, when entering the hole 121a of the first die 121, a self-aligning force acts to align the core. However, since this fiber is not well aligned when exiting from the hole 123a through the second resin reservoir chamber 125, the first die 12
The centers of the hole 121a of the first die 122 and the hole 122a of the second die 122 must be aligned. These holes 121a and 122
Adjustment of the center with respect to a can be performed by moving the second die 122 in the horizontal direction using the uneven thickness adjusting screw 130.

Using the two-layer coating die of this example, two layers were simultaneously coated using an ultraviolet curable resin called FI950XO65 manufactured by Desoto Co. as the -layer resin and 950XO44 manufactured by Desoto Co. as the second layer resin.

First, 130 four thickness unevenness adjusting screws were pushed in evenly to obtain a state similar to that of a conventional two-layer coating device, and when two layers were coated simultaneously, as shown in Figure 2 was gotten.

Note that this optical fiber has a first layer 3a with respect to the fiber 3.
Although there was no uneven thickness, the second layer 3b had a large uneven thickness.

Next, while checking the uneven thickness by cross-section like this,
When the position of the second die 122 is adjusted using the thickness unevenness adjustment screw 130, as shown in FIG. No optical fiber was obtained.

Note that the thickness unevenness evaluation can be more easily performed by using the scattering state of laser light when coating with an optically transparent resin.

In the above embodiment, the second die 122 is movably provided with respect to the first die 121, but it goes without saying that the same effect can be obtained even if the relationship is reversed. Further, the present invention is not limited to two-layer coating, and can also be applied to multi-layer coating.

In the hypothetical embodiment, a two-layer coating die used for coating an optical fiber has been described, but it goes without saying that the die can also be used to coat a wire with two layers at the same time.

<Effects of the Invention> As specifically explained above along with the examples, by using the coating die of the present invention, the conventional problem of uneven thickness can be solved and two layers can be coated simultaneously on the running wire. Now I can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a two-layer coating die according to an example of the present invention, and FIG. 2 is a sectional view showing test results in this example.
FIG. 3 is a schematic diagram showing a conventional two-layer coating process, and FIG. 4 is a sectional view of a conventional two-layer coating die. In the drawings, 121 is a first die, 122 is a second die, 123 is a point, 124 is a first resin reservoir, 125 is a second resin reservoir, and 130 is a thickness unevenness adjusting screw.

Claims (1)

[Scope of Claims] 1) A coating die that simultaneously applies two layers of low-viscosity liquid resin to the wire, the coating die comprising first and second dies each having a hole through which the wire passes; A coating die characterized in that it comprises centering means for moving and adjusting the relative position of the wire rod and the second die in a direction perpendicular to the running direction of the wire rod. 2) A second die is provided on the first die so as to be movable in a direction perpendicular to the running direction of the wire rod, and a push/pull bolt provided on the first die serves as centering means. A two-layer coating die according to scope 1.