JPS602704A - Spinneret for melt spinning and its preparation - Google Patents

Abstract

PURPOSE:To obtain a spinneret having plural smooth nozzles with uniform diameter in a short time, by forming a lower hole at a specific position of a nozzle plate, inserting a hollow pipe to the lower hole by pressure and forming spinning nozzle plates. CONSTITUTION:The lower hole 4' is formed on the nozzle plate 2 such as stainless steel plate, etc. at a position in which a spinning nozzle should be made, and the hollow pipe 4 is inserted into the lower pipe 4' by pressure. If necessary, the end part of the hollow pipe inserted by pressure is abraded in such a way that it has the same plane as that of the nozzle plate or is processed into a given shape, to give the desired spinneret having extremely smooth inner face, uniform aspect ratio, and spinning nozzle holes having high accuracy. Preferably plural spinning nozzle holes are made in one line in the direction of the circumference or in plural lines with the line as the center.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spinneret having a spinning nozzle that can be suitably used for melt spinning such as pitch-based carbon fiber spinning, and a method for manufacturing the same.

Conventionally, spinning of materials such as pitch-based carbon fibers has been carried out using a spinneret having a number of nozzle holes formed in one or more rows in the circumferential direction.

Thin III! In order to melt-spun two fibers in a stable state for a long period of time, it is important that the nozzle hole provided in the spinneret be sufficiently small, have a smooth inner surface, and have the same inner diameter, that is, a uniform aspect ratio.

In producing such a spinneret, the nozzle holes have conventionally been generally drilled through a nozzle plate using a drill or an electron beam. However, the drilling method using a drill has various problems as the nozzle hole diameter becomes smaller. The first reason is that it is difficult to process with high precision. In other words, the drill itself has a tendency to swing when rotating, and when drilling the nozzle plate, it swings and rotates due to drilling resistance, and as shown in Figure 1, the diameter of the hole at the beginning and end was different. It becomes a hole.

Furthermore, as the diameter of the drill becomes smaller, the blade dulls more quickly and the drilling ability is significantly reduced. The blade of such a small-diameter drill cannot be polished, requiring frequent drill replacement, and the frequency of breaking and removing the drill increases, which not only reduces drilling efficiency, but also reduces the manufacturing cost of the spinneret itself. Let cost be a dog.

The electron beam method was proposed to solve the drawbacks of the drilling method using a drill, but the electron beam stays inside the hole during drilling, resulting in the formation of swollen soft stools, as shown in Figure 2. Holes are formed, and such a nozzle has the disadvantage of poor fiber orientation.

Therefore, the main object of the present invention is to provide a spinneret that is equipped with a plurality of nozzles having smooth and uniform hole diameters and can stably spin thin fibers such as pitch-based carbon fibers for a long period of time. It is.

It is another object of the present invention to provide a spinneret with a plurality of nozzles having smooth and uniform pore diameters that can be manufactured with great precision (and in a single time and efficiency). .

As shown in FIG. 3, in the spinneret 1 according to the present invention, a hollow pipe 4 having a desired diameter is attached to a nozzle plate 2 having a predetermined thickness by, for example, press fitting, and a spinning nozzle hole is formed. It is constructed by causing the formation of

Normally, a 4N stainless steel plate (SUS5o4) is suitable for the nozzle plate 2 in the case of melt spinning of pitch-based carbon fiber, etc., and the hollow pipe 4 has an inner diameter of 0.55mm like a hypodermic needle.
It is a stainless steel tube with an outer diameter of 1.5 mm. or,
The nozzle holes formed by the hollow pipe 4 can be arranged in a desired arrangement on the nozzle plate 2, but for example, in the case of melt spinning the pitch-based carbon fiber described above, the nozzle holes are arranged in the nozzle plate 2 in one row or in the circumferential direction. Multiple rows will be arranged concentrically.

Spinnerets 1a and 1b according to other embodiments of the present invention are illustrated in FIGS. 4 and 5. Spinneret 1a shown in FIG.
In this case, the hollow pipe 4 forming the nozzle hole is not provided over the entire thickness of the nozzle plate 2,
It is disposed on the spinning side of the nozzle plate 2 over approximately half of its thickness. The melt spun material inflow side of the nozzle plate 2 is formed with an introduction hole 6 communicating with the nozzle hole formed of a hollow pipe 4 in order to guide the flow of the material into the nozzle hole.

The spinneret 1b shown in FIG. 5 is the spinneret 1b shown in FIG.
8, but differs in that the hollow pipe 4 protrudes somewhat toward the spinning side of the nozzle plate 2 to form a protruding nozzle.

The spinneret 1b having such a protruding nozzle is characterized by good peelability between the melt spun material and the spinneret. Further, in order to reinforce the protrusion on the spinning side of the hollow pipe 4, it is preferable to fix the protrusion to the nozzle plate 2 by brazing 8.

Next, a method for manufacturing a spinneret according to the present invention having the above structure will be explained.

Referring to FIG. 6, a pilot hole 4' is formed in the nozzle plate 2 at a position where a spinning nozzle is to be formed (FIG. 6a).
. Next, the hollow pipe 4 is press-fitted into the lower hole 4° (FIG. 6b). The press-fitting operation is performed, for example, when the hollow pipe 4 is made with an outer diameter of 1
51! When a stainless steel pipe with an inner diameter of 0.55 m and 7 g is used, the inner diameter of the pilot hole 4' is finished within 15 minutes, the nozzle plate 2 is heated to 150 to 300°C, and the hollow pipe 4 is left at room temperature or cooled. This is done by inserting the nozzle plate 2 into the pilot hole 4' and then cooling the nozzle plate 2.

Subsequently, if the hollow pipe 4 protrudes beyond the nozzle plate 2, the protruding part of the hollow pipe 4 is ground so as to be flush with the surface of the nozzle plate 2 (FIG. 6C).

FIG. 7 illustrates a method for manufacturing the spinneret shown in FIG.

In this embodiment, the lower holes formed in the nozzle plate 2 include a small diameter portion 4'' on the spinning side of the nozzle plate 2, a large diameter portion 4'' on the melt spun material inflow side of the nozzle plate 2,
It consists of a transition part 41 that connects the small diameter part 4' and the large diameter part 4''.The hollow pipe 4 is press-fitted into the small diameter lower hole 41 in the same manner as described above (FIG. 7b). The portion protruding upward from 4' expands toward the transition lower hole 41,
It is closely attached to the wall of the lower transition hole 4"1 (FIG. 7C). Next, the hollow pipe portion protruding from the spinning side of the nozzle plate 2 is ground to make it flush with the surface of the nozzle plate 2. Also, if desired, the portion of the hollow pipe 4 that is brought into close contact with the lower transition hole 4'' can be polished with a special tip and the bent portion removed. Large diameter part 4111 and transition part 4°
forms the introduction hole 6.

FIG. 8 illustrates a method for manufacturing a spinneret with protruding nozzles. The process of drilling the pilot hole into the nozzle plate 2 and press-fitting the hollow pipe into the nozzle plate 2 (FIGS. 8a and 8b) is the same as that described in connection with FIG. The only difference is that it protrudes longer outward from the spinning side. The upper end of the hollow pipe 4 press-fitted in this manner expands into the lower transition hole as described above, and brazing 8 is performed on the outer periphery of the protruding portion of the hollow pipe 4 (Fig. 8). C). Such brazing can be carried out in a conventional manner, for example by heating in an electric furnace. After the brazing work is completed, the hollow pipe portion and brazing portion protruding from the spinning side of the nozzle plate 2 are polished into a predetermined shape.

Also, if desired, the portion of the hollow pipe 4 that is brought into close contact with the lower transition hole can be polished with a special tip and the bent portion removed (FIG. 8d).

The present invention, which is constructed as described above, uses a ready-made hollow pipe with good roundness and straightness as a spinning nozzle as it is, so it is possible to create a highly accurate spinning nozzle with an extremely smooth inner surface and a uniform aspect ratio. A spinneret having the following properties can be provided.

Further, according to the present invention, a multi-hole nozzle spinneret having a large number of highly accurate nozzle holes can be provided easily and at low cost. Furthermore, the use of the spinneret according to the present invention has the advantage that pitch-based carbon fibers and the like can be stably spun over a long period of time.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views showing the nozzle holes of a conventional spinneret. FIG. 3 is a sectional view showing one embodiment of the nozzle hole of the spinneret according to the present invention. 4 and 5 are cross-sectional views showing other embodiments of the nozzle hole of the spinneret according to the present invention. FIGS. 6(a) to (e), FIGS. 7(a) to (d), and FIGS. 8(a) to (d) are explanations of each manufacturing process to explain the manufacturing method of the spinneret according to the present invention. It is a diagram. 1: Spinneret 2: Nozzle plate 4: Hollow pipe 8: Brazing Fig. 1 Fig. 2 Fig. 6 Fig. 7

Claims (1)

[Scope of Claims] 1) A spinneret for melt spinning, characterized in that a hollow pipe having a predetermined inner diameter is attached through a nozzle plate to form a spinning nozzle hole 2) The spinning nozzle hole is arranged in the circumferential direction The spinneret for melt spinning according to claim 1, wherein the spinneret is formed by forming a plurality of cages in one row or in a plurality of rows concentrically. 3) Processing a pilot hole in the nozzle plate, press-fitting a hollow pipe into the pilot hole, and, if necessary, polishing the end of the press-fitted hollow pipe to the same plane as the nozzle plate or to a predetermined shape. A method for manufacturing a spinneret for bath melt spinning, comprising: 4) The method according to claim 3, wherein a plurality of pilot holes are formed in one row or in a plurality of concentric rows in the circumferential direction of the nozzle plate. 5) The press-fitting process is carried out by heating the nozzle plate to 150°C to 300°C, leaving the hollow pipe at room temperature or cooling it, inserting the hollow pipe into the nozzle plate, and then cooling the nozzle plate. The method described in Scope No. 3. 6) The method according to claim 3, wherein the pilot holes are bored with the same diameter in the thickness direction of the nozzle plate, and the hollow pipe is press-fitted over the entire length of the pilot holes. 7) The method according to claim 3, wherein the pilot hole is comprised of a large diameter part and a small diameter part, and the hollow pipe is press-fitted into the small diameter part. 8) The method according to claim 7, wherein the hollow pipe is disposed over the entire length of the small diameter section. 9) The method according to claim 7, wherein the hollow pipe is arranged to protrude outward from the nozzle plate from the lower hole of the small diameter portion. 10) The method according to claim 9, wherein the outwardly projecting hollow pipe portion is brazed to the nozzle plate.