JPS61289140A - Production of polyester crimped fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing polyester crimped fibers.

More specifically, it relates to a method for producing crimped polyester fibers that improves the spinning cooling process, which is particularly problematic when spinning at a low spinning speed of less than 100 m/sin and subsequently drawing and crimping. It is.

(Prior art) Conventionally, as a method for producing polyester fibers that can be used for practical purposes, 1. Normally, undrawn yarn obtained by melt-spinning polyester is first taken up as a subtow on a bobbin, can, etc. 1. Then, this undrawn yarn is A two-step method is adopted in which a large number of fibers are bundled, supplied to a stretching process, and then stretched. According to this method, polyester fibers can be stably obtained.

The spinning process and drawing process must be installed as independent systems, which requires a large space to store the equipment and the undrawn yarn subtow, which is disadvantageous in terms of operation and cost for low-volume, high-mix production. be.

In recent years, an attempt has been made to obtain a practically usable polyester fiber by a direct spinning/drawing method without going through two steps, as disclosed in JP-A-52-107316.

However, since this method uses a spinning speed of 100 to 400 m/min, the tow speed after stretching is 1500 m/min.
In order to apply crimps to the stretched tow, it is necessary to first store it in a can and then stack a plurality of tows to apply the crimps. In other words, in the production of staple fibers,
Generally, crimp is applied using the push-in crimp method,
Due to equipment limitations, this method currently has a distance of approximately 500m/
This is because the speed of sin is the limit, and this speed is the upper limit of the drawing speed of the short fiber tow in the direct spinning draw-crimping method.

(Problem to be solved by the invention) In this way, the stretching speed is at most 500 m/lll.
The feeding speed of undrawn polyester yarn directly fed to the 1n drawing process is 100 m/mi considering its drawing ratio.
It is necessary to make n grooves. however.

If such extremely low speed spinning is performed, the liquid yarn that has not solidified after spinning will elongate and fall due to its own weight, making spinning difficult. Since the ejection unevenness is significant and unstable, there are problems such as thread breakage occurring during stretching, and at present, a technology that can be put to practical use has not yet been established.

The technical object of the present invention is to provide a method that can improve the above-mentioned drawbacks and continuously produce polyester crimped fibers of excellent quality with good operability.

(Means for Solving the Problems) That is, one aspect of the present invention is to provide an undrawn polyester yarn melt-spun at a speed of 100 m/mfn.

For yarns spun from a spinneret when producing polyester crimped fibers by the direct spinning draw-crimping method, which involves stretching without winding or storing and then crimping.

(a) The cold air blowing start position is within 100 mm from the spinneret surface, and the mouth is from a cold air blowing surface with a length of 15 m or more and 50 m or less. (c) Cool air is blown from parallel to 40 degrees to the spinneret surface for cooling. The gist of this paper is a method for producing crimped polyester fibers.

As the polyester in the present invention, a polyester having ethylene terephthalate as a main repeating unit is preferably used, but polyesters generally used industrially as fibers, such as those to which modifiers, colorants, etc. are added as necessary, are preferably used. Polyester can be used.

Hereinafter, one embodiment of the present invention will be described in further detail with reference to the accompanying drawings.

The polyester polymer is fed into a conventional spinning machine, melted, and then expelled through a suitable spinneret. On this occasion,
The discharge temperature and discharge conditions of the molten polymer may be normal spinning conditions, and are not particularly limited, but from the purpose of the present invention, it is particularly useful when using a porous spinneret with 5000 or more holes per spinneret. The molten polymer is distributed to the distribution plate 2 in the metal bag 1. It is spun through spinneret 3.

It becomes thread Y. The yarn Y is cooled by cold air flowing in the direction of the arrow a from the cold air blowing device 4 installed substantially perpendicular to the running direction of the yarn Y shown by the arrow S. After applying the oil at the guide 6, the direction is changed using the guide 6.
The yarn is taken at a speed of less than 0 m/win, aligned with yarns from multiple spindles as necessary, and guided through a normal drawing process and a crimp process (none of which are shown).

The cold air flowing from the cold air blowing device 4 in the direction of arrow a contacts or passes near the yarn Y, and becomes an accompanying airflow of the yarn Y. Here, the yarn Y immediately after melt spinning is cooled by the cold air blown from the cold air blowing device 4, but the cold air blowing start position of the blowing device is set to enhance the cooling effect and cut the yarn by its own weight.
Alternatively, in order to prevent the generation of cohesive yarns, it is necessary to keep the distance within 100 m from the surface of the spinneret 3, preferably about 50 m. In addition, the length of the cold air blowing surface is generally several hundred meters.
The length of the blowing surface is extremely short (15 mm or more, 50 m) compared to several tens of cm, which is the length of the blowing surface used when the spinning speed is 15 mm or more.
It is necessary to do the following. When the length of the cold air blowing surface exceeds 50+n, the amount of blown cold air that becomes the accompanying airflow of the yarn Y increases, the yarn is pulled downward by this accompanying airflow, and as a result, the spinning speed increases. There will be excess thread and the thread will break.

On the other hand, if the length of the cold air blowing surface is less than 15n, the threads Y will not be sufficiently cooled and the single threads will stick together, which is not preferable.

The blowing angle of the cold air from the blowing device 4 to the yarn Y is in the range from parallel to the spinneret surface to 40 degrees, preferably from 15 degrees to
It needs to be 30 degrees. That is, immediately after spinning, cold air is blown approximately perpendicularly or in the direction of the spinneret (obliquely upward) to the yarn located at a very short distance within lOO1 from the spinneret surface to cool the yarn. speed 100
Draft breakage caused by the weight of the liquid yarn immediately after spinning, which occurs when melt spinning is less than m/+win, is prevented, and there is no fusion between single yarns caused by yarn wobbling, resulting in no variation in quality and excellent uniformity. It becomes a thread.

On the other hand, the cold air blowing angle from the cold air blowing device 4 is
When the direction is downward rather than parallel to the plane, the length of the cold air blowing surface described above becomes
As with the case where the length exceeds 0 mm, thread breakage is likely to occur.

Furthermore, if the cold air blowing angle exceeds 40 degrees with respect to the surface of the spinneret 3, the nozzle surface will be cooled by the blowing air, and as a result, discharge unevenness will become significant and thread breakage will occur, which is unsuitable.

The yarn that has been subjected to the above cooling treatment is first heated in a heating row, and then drawn to a predetermined draw ratio in a normal drawing process, and if necessary, after heat centrifugation.

The polyester crimped fibers are crimped and have practically excellent physical properties.

(Example) Examples of the present invention are shown below, but the present invention is not limited thereto.

Examples 1 to 5 and Comparative Examples 1 to 5 Polyethylene terephthalate having an intrinsic viscosity [η) of 0.68 was melted and spun from a spinneret, and after cooling, it was stretched without winding. 4! When applying compression and cutting, the first
The various cooling conditions shown in the table were adopted.

The production of polyester crimped fibers was carried out over a period of 15 days. The spinning temperature was 300°C, the number of spinneret holes was 8000, the cold air was 30°C, and the blowing speed was 1.
．． After taking it off at a speed of 7 m/sec and 30 m/win, it was oiled, immediately stretched 6 times, and crimped using a push crimper.

It was cut to 511m. Table 1 shows the physical properties of the obtained short polyester fibers.

Table 1 *2: The force meter could not be measured after the pull-up device got stuck.

As is clear from Table 1, the yarns obtained in Examples 1 to 5 all had little yarn breakage (the single yarn fineness variation rate was also good, and the 1 strength elongation was comparable to that of the two-step method). Polyester crimped fibers were obtained.Furthermore, in the samples for measuring the single yarn fineness fluctuation rate of the yarns obtained in Examples 1 to 5, there was no fusion between single yarns, but in Comparative Example 2.3, there was no fusion between single yarns. Fusion between single filaments was observed in the sample.

(Effects of the Invention) As described above, the present invention is advantageous in that when producing polyester crimped fibers by the direct spinning draw-crimping method at a spinning speed of less than 100 m/min, the cold air blowing start position is set at one point from the spinneret surface.
Since the spun yarn is cooled by blowing cold air from a cold air blowing surface with a length of 151 to 50 mm or less from a range of 40 degrees parallel to the spinneret surface, draft breakage due to the yarn's own weight is avoided. thread breakage due to accompanying air currents,
This method has the advantage that polyester crimped fibers of excellent quality can be produced continuously with good operability without the occurrence of troubles such as fusion between single yarns due to yarn wobbling.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view showing a polyester melt spinning apparatus used in one embodiment of the present invention. 1; Spinneret pack 2; Distribution plate 3; Spinneret 4; Cold air blower Y; Yarn

Claims (1)

[Claims] (1) Polyester crimped fibers are produced by a direct spinning draw-crimping method in which undrawn polyester yarn melt-spun at a speed of less than 100 m/min is drawn without winding or storing, and then crimped. When manufacturing, for the yarn spun from the spinneret, (a) The cold air blowing start position is within 100 mm from the spinneret surface (b) From the cold air blowing surface with a length of 15 mm or more and 50 mm or less c) Parallel or parallel to the spinneret surface A method for producing crimped polyester fibers, which is characterized by cooling by blowing cold air from a range of 40 degrees.