JPH0192418A - Method for spinning metallic fiber - Google Patents

Abstract

PURPOSE:To reduce dripping, clogging, abnormality in the discharge direction during spinning, etc., and maintain spinning stability for a long period, by controlling oxygen concentration in a spinneret atmosphere within a specific range in discharging a molten metal through a spinneret and forming a fiber therefrom. CONSTITUTION:A molten metal (e.g. Pb, Sn, Ni, Zn, Al, Cu, Pb/Sn or Pb/Sb alloy) is discharged through a spinneret and formed into a fiber. In the process, oxygen concentration in the spinneret atmosphere is controlled to 0.3-15%, preferably 0.5-10%.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the spinning of metal fibers that has excellent long-term spinning stability with less dripping, clogging, and abnormalities in the direction of discharge during spinning in the spinneret hole. It is about law.

[Prior Art] Several proposals have already been made in Japanese Patent Application Laid-Open No. 41913/1983 regarding methods for stably spinning metal into fibers by melt spinning, but it is difficult to control the oxygen concentration in the spinneret atmosphere. No attempt has been made to achieve long-term spinning stability.

[Problems to be solved by the invention] When melt spinning of metal fibers is continued for a long period of time, some filaments develop an abnormality in the discharge direction at the outlet of the spinneret hole, and are spun at an angle of several tens of degrees from the vertical direction. It becomes like this. When this happens, during multifilament spinning, the filaments interlock and collide with each other near the outlet of the spinneret. Since the metal was still in a molten state very close to the outlet of the die, a problem arose in that the metal was shot and the fibers were not formed properly.

Further, such a phenomenon in which the ejection direction changes is an early stage of an abnormality in the mouth hole, and eventually becomes cotton thread and generates drips. Furthermore, there was a problem in that clogging occurred, making it impossible to continue spinning, and requiring 1q of spinnerets to be replaced.

This abnormality in the spinneret hole is due to the generation and growth of foreign matter around the discharge port or inside the discharge hole, and suppressing the generation and growth of such foreign matter is an issue in achieving stable spinning. Ta.

In view of the drawbacks of the prior art, the present invention aims to achieve excellent long-term spinning stability.

[Means for Solving the Problems] The present invention provides a method for forming fibers by discharging from a melting nozzle, in which the oxygen concentration in the nozzle atmosphere is set to 0°5% or more15,
% or less.

Inclination of the discharge direction, dripping, and clogging at the nozzle hole are caused by foreign matter generated around and inside the nozzle hole. Produced as a result of reaction with gas.

In the case of metals that can be turned into fibers by discharging molten metal into the atmosphere, the oxide film that is formed on the surface of the molten metal liquid column immediately after discharge plays an important role, stabilizing the liquid column and preventing it from breaking. Prevents fibers.

However, on the other hand, if oxides are generated around or inside the spinneret hole, it will cause spinning failure.

Therefore, it is sufficient that the spun metal liquid column is stabilized by an oxide film and has a concentration of oxygen that makes it possible to form fibers.If the oxygen concentration is too high, the oxidation reaction will occur excessively and This is undesirable because oxides are generated in the surrounding area and inside the mouth hole due to diffused oxygen. To carry out the present invention, it is necessary to keep the oxygen concentration in the mouth atmosphere from 0.3% to 15%, preferably from 0.3% to 10%, particularly preferably from 0.5% to 10%. It is desirable to do so. If the oxygen concentration is lower than 0.3%, the spun liquid column becomes unstable and fiber formation itself becomes impossible, which is not preferable. Also, if it is larger than 15%,
is almost equal to the agricultural level (oxygen in the atmosphere), so the effect of suppressing the production and growth of foreign substances is not observed at all, which is not preferable.

The molten metals mentioned here include Pb, Sn, Ni, Zn,
Metals such as AD, Cu, Pb/Sn alloy, and Pb/Sb alloy that can be spun into the atmosphere to form fibers are particularly preferred, but other metals can also combine with oxygen and become insoluble in the molten metal. It is not limited to these, as it often contains impurities.

[Effect] This is thought to be due to the fact that by lowering the oxygen concentration in the nozzle atmosphere, oxidation of the metal is suppressed, making it difficult for oxides to form and grow around the nozzle hole and inside the discharge hole.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

[Example] Example 1 Electrolytic lead (purity of 99.9% or more) was melted in air at 340°C, and spun into the atmosphere through a nozzle whose surface temperature was set to 340°C by pressurizing N2 gas. produced fibers. N2 gas was fed into the spinning tube that was continuously installed at the bottom of the spinneret to maintain the oxygen concentration in the spinneret atmosphere at 5%.

Although a spinneret with a hole diameter of 50 μm and 300 holes was used, the spinning process was extremely stable, and 1 ton of lead fiber could be produced without replacing the spinneret.

Comparative Example 1 In the same manner as in Example 1, lead was melted and spun into the atmosphere by pressurizing N2 gas to produce fibers. No gas was supplied to the spinning tube and it was left in the atmosphere. (Oxygen degree, about 20%) From the time about 600 kg of lead fibers were spun, fine threads started to form, and eventually dripped, making it impossible to continue spinning any further.

Comparative Example 2 In the same manner as in Example 1, molten lead was spun into the atmosphere through a nozzle with a hole diameter of 50 μm and a number of holes of 300, and it was confirmed that fibers were normally formed. Next, N2 gas is sent into the spinning tube that is connected to the spindle to reduce the oxygen concentration to 0.
．． When we started maintaining it at 1%, the fibers were no longer forming and became droplets.

[Effects of the Invention] According to the present invention, the life of the spinneret is significantly extended, and spinning can be performed for a long time without replacing the spinneret. Since the manufacturing process has been stabilized, productivity is improved and it is also effective in reducing manufacturing costs.

Furthermore, the present invention is particularly effective when using a nozzle with a small mouth diameter, and the hole diameter is 100μ or less, especially 5.
It is extremely effective when using a cap with a diameter of 0 μ or less.

Claims (1)

[Claims] (1) In a method of discharging molten metal from a nozzle to form fibers, the oxygen concentration in the nozzle atmosphere is set to 0.3% or more and 15%.
A metal fiber spinning method characterized by controlling as follows.