JPS5940923B2 - Melt spinning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for melt spinning synthetic fibers having a single filament fineness of 1 denier or less using a cross-blown spinning tube at a take-up speed of 3000-7 Z/min or more.

Conventionally, cooling gas for melt-spun yarn is blown out from one side of the spun yarn, the cooling gas is blown almost orthogonally to the spun yarn, and then the cooling gas is blown against the cooling gas blowing surface. Two types are widely used: a so-called side-blown spinning tube that discharges gas from the opposite surface, and a cylindrical spinning tube that blows cooling gas from the entire circumference of the spun yarn.

Among these, the former side-blown spinning tube has an open surface opposite to the cooling gas blowing surface and is easy to work with.
It is often used for melt spinning multifilaments for clothing, which have a relatively small number of single yarns.

When melt spinning is performed using such a cross-blown spinning tube, if the single filament fineness of the spun yarn becomes small, single filament breakage will occur during the spinning process due to slight disturbance of the cooling gas, and furthermore, fineness unevenness and physical properties will be affected. Spots are more likely to occur.

This tendency becomes particularly noticeable as the spinning take-off speed increases.

The present inventor has discovered that when fine-grained synthetic fibers with a single filament fineness of 1 denier or less are drawn and melt-spun at a high speed of 3000772/min or more, they are cooled under normal conditions using a conventional side-blown spinning tube. However, the problem encountered was that single fiber breakage occurred frequently in the spun yarn, making it impossible to perform stable spinning, and furthermore, uneven fineness and physical properties occurred, making it impossible to obtain a yarn of good quality.

As a result of intensive studies to solve these problems, we found that by reducing the blowing speed of the cooling gas, outside air can be sucked into the spinning tube from the surface opposite to the cooling gas blowing surface, and the cooling gas blowing surface and The inventors have discovered that it is sufficient to provide a rectifying device on the outside air suction surface, and have arrived at the present invention.

That is, in the present invention, synthetic fibers having a single filament fineness of 1 denier or less are processed using a cross-blown spinning tube. OOO? When performing melt spinning at a take-up rate of 7 Z/min or more, a gas rectifier is provided on the cooling gas blowing surface of the cross-blown spinning tube and the surface opposite to the blowing surface, and a gas rectifying device is provided on the cooling gas blowing surface of the cross-blowing spinning tube and on the surface opposite to the blowing surface. This melt-spinning method is characterized by blowing out cooling gas, and also rectifying outside air from a surface opposite the blowing surface and suctioning it into the spinning cylinder to cool the spun yarn.

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

FIG. 1 is a longitudinal sectional view showing an example of a side-blown spinning tube used in the present invention.

In the figure, 1 is the base, 2 is the cooling chamber, and 3 is the filter provided on the cooling gas blowing surface B, or the same is the blowing surface B.
A rectifying device provided on the surface S opposite to the cooling gas blowing surface B.

The yarn Y discharged from the spinneret 1 so that the single yarn fineness is 1 denier or less is transferred to the cooling chamber 2 and the cooling gas blowing surface B.
It is cooled by cooling gas that is filtered and rectified through a filter 3 and a rectifier 4 provided in the spinning tube and blown into the spinning tube.

At the same time, from the surface S facing the cooling gas blowing surface B, outside air is drawn into and introduced into the spinning cylinder through the straightening device 5, and the spinning tube is also cooled by the straightened outside air.

What is particularly important here is to adopt cooling conditions such that outside air is sucked from the surface S facing the cooling gas blowing surface B.

In order to suck outside air from the opposing surface S, the cooling gas blowing speed may be set lower than the blowing speed normally used, and the suction effect due to the conditions of high-speed running may be exerted.

By setting the cooling gas blowing speed to 30 cm/sec or less, particularly preferably from 5 to 25 CW1/sec, outside air can be drawn in from the opposing surface S.

If the cooling gas blowing speed becomes too high, the cooling gas blown into the spinning cylinder from the blowing surface B will be discharged from the opposing surface S, and the suction and introduction of outside air will not be performed, so that the spun yarn Single thread breakage, fineness unevenness, and physical property unevenness occur.

By blowing cooling gas from one side of the spun yarn and sucking in outside air from the opposite side, the blown cooling gas and the sucked outside air begin to balance, allowing stable spinning and uniform yarns. be.

In the present invention, a rectifying device 4.5 is further provided on both the cooling gas blowing surface B and the surface S opposite to the blowing surface. It is necessary to do so.

As the rectifying device, a device having a gas rectifying effect, such as a device consisting of a rectifying plate as shown in FIG. 2 or a honeycomb structure device, is used.

FIG. 2 is a perspective view showing an example of a rectifying device used in the present invention, in which rectifying plates 8, 9, 10, 11, . They are provided in multiple stages, and the gas is rectified by passing between the current plates.

Although it is preferable that the rectifying device be provided over the entire length of the cooling gas blowing surface B and the opposing surface S, it is sufficiently effective to provide it only in the upper half.

As explained above, according to the method of the present invention, when melt-spinning fine synthetic fibers with a single filament fineness of 1 denier or less at a high speed of 3.000 m/min or more, single filaments are added to the spun yarn. Stable spinning is possible without breakage, uneven fineness,
A yarn of good quality with less physical unevenness can be obtained.

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

Examples 1-4. Comparative Examples 1 to 2 Polyethylene terephthalate (containing 0.3% titanium oxide by weight) with an intrinsic viscosity [η] of 0.64 measured with an O-tetrachlorophenol solution at 35°C was prepared with 72 pores with a pore diameter of 0.15.
Discharge rate 13.1 from a separate spinneret at a temperature of 298℃
It was extruded at a speed of S'/min and cooled by changing the cooling gas blowing rate in various ways using a side-blown spinning tube with a rectifier shown in Fig. 1.
It was taken up at a take-up speed of 800 m/min and wound up on a wine goo.

The cooling gas blowing surface is 10mm from the position 90rrrrn below the cap.
It extended for up to 1000 yr, and a rectifier was provided over its entire length.

The rectifying device used was a device shown in FIG. 2 in which rectifying plates were provided in multiple stages, and the spacing between the rectifying plates was approximately 50 mm.

On the other hand, for comparison, spinning was carried out using a conventional side-blown spinning tube without the straightening device and under the same conditions as in Example 2.

Number of single yarn breaks that occur in the spun yarn during the spinning process (times/day)
, and fineness unevenness (U%) were measured and shown in the following table.

In addition, Examples 1 to 4. In Comparative Example 2, the outside air is sucked in from the surface facing the cooling gas blowing surface, but in Comparative Example 1, the cooling gas is blown out from the surface facing the cooling gas blowing surface, and the outside air is not sucked.

As is clear from the table, according to the method of the present invention, yarn breakage hardly occurs, the spinning condition is stable, and yarns of good quality with few irregularities can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an example of a side-blown spinning tube used in the present invention, and FIG. 2 is a perspective view of the rectifying device shown in FIG. 1. Y is a spun yarn, B is a cooling gas blowing surface, S is a surface facing the cooling gas blowing surface, 4 and 5 are rectifiers, 8°9.10,1
1 indicates a rectifying plate.

Claims (1)

[Scope of Claims] 1. When melt-spinning synthetic fibers with a single filament fineness of 1 denier or less using a cross-blown spinning tube at a take-up speed of 3,000,772/min or more, the cooling gas blowing surface of the cross-blown spinning tube A gas rectifying device is provided on the surface opposite the blowing surface, and the cooling gas is blown out from the blowing surface toward the spun yarn, and the outside air is also rectified from the surface opposite the blowing surface to flow into the spinning tube. A melt spinning method characterized in that the spun yarn is cooled by suctioning the spun yarn. 2 Cooling gas blowing speed from the cooling gas blowing surface is 30Cm
2. The melt spinning method according to claim 1, wherein the spinning speed is less than /second. 3 The cooling gas blowing speed from the cooling gas blowing surface is 5 to 25.
The melt spinning method according to claim 1, wherein the spinning speed is CWl/sec.