JPS6136088B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing synthetic fiber spun yarn by tension-cut spinning.

Normally, in order to obtain synthetic fiber spun yarn by the tension-cutting method, the raw material polymer is first spun and stretched to form a tow, which is then tension-cutted into short fiber bundles, which are then subjected to an appropriate spinning process to form the spun yarn. It is normal to form a As a result of a detailed study of these processes, the present inventors created a tow in which the undrawn yarn after spinning was not drawn, that is, it was not stretched, but conversely contracted by heating. It was discovered that by cutting, a spun yarn with a softer texture than conventional yarns could be obtained.

That is, the present invention is characterized in that a thermoplastic polymer is spun into a continuous yarn, the continuous yarn is heat treated in a relaxed state, and then tension cut is made into a yarn without substantially hot drawing. This is a method for producing spun yarn. below,
The present invention will be explained in detail.

The thermoplastic polymer of the present invention includes polyester,
Any thermoplastic polymer may be used as long as it can be used to produce thermoplastic synthetic fibers such as polyamide and polypropylene, but polyester is preferred from the viewpoint of texture and heat resistance. In the present invention, such a thermoplastic polymer is spun into a continuous yarn, but the spinning speed is preferably 2000 m/min, which is higher than the commonly used spinning speed of 500 to 1000 m/min. Of course, it is also possible to use a yarn spun within a range of 100 to 200 min, but in this case, the adjustment range of the heat treatment temperature in the relaxed state described below is narrow. However, if the spinning speed is 2000 m/min or more, oriented spinning will be performed, and the control range of the heat treatment temperature will be expanded depending on the internal structure of the spun fibers.

Next, in the present invention, the continuous yarn described above is heat treated in a relaxed state. This heat treatment may be performed as long as the continuous yarn can be thermally shrunk to some extent, but it is desirable to shrink the continuous yarn by 10% or more if possible.

Therefore, the heat treatment temperature must be at a level that allows the continuous yarn to sufficiently shrink and not cause fusion, and this varies depending on the type of tow, spinning conditions, etc.
Care must be taken to satisfy the temperature conditions suitable for the tow at that time.

For example, if the continuous yarn of polyester is spun at a spinning speed of 500 to 1000 m/min, the continuous yarn must be supplied in sufficient quantity to ensure sufficient shrinkage and to prevent fusion. (i.e., overfeed) and dry heat at a temperature of 100°C.
Heat treated at around ℃.

In addition, if the polyester continuous yarn is spun at a spinning speed of 2000 m/min or more, the heat treatment temperature may preferably be in the dry heat range of 150 to 200° C. while maintaining the yarn in a relaxed state. If the spinning speed is 2000 m/min or more, the range of the heat treatment temperature is wider, so there is no need to make delicate adjustments like the heat treatment temperature when the spinning speed is 500 to 1000 m/min.
As already mentioned, it is desirable to spin continuous yarn at a spinning speed of 2000 m/min or more.

Next, the present invention is a method for producing a spun yarn, in which the continuous yarn heat-treated as described above is then tension cut into a yarn without being substantially hot-stretched. Continuous heat treatment under the conditions described above causes sagging,
Twitches, loops, etc. often occur, and it may be necessary to pull them in advance and sometimes stretch them slightly to make them even, but even in that case, it is usually done. Complete hot stretching must be avoided.

Regarding tension cutting, it is possible to create a sliver by cutting it at a drafting ratio of several times, and then drafting it as appropriate and spinning it, or by cutting it at a high drawing ratio of several tens of times, and then using a fluid swirling nozzle, etc. It is also possible to continuously produce yarn directly by conjugating with . In addition, the length of the tension cut at this time is generally better if it is long (for example, 100 mm or more).By doing so, the degree of conjugation or the number of twists of the twisted yarn can be lowered, and the binding force between the fibers is weakened. , a softer texture effect can be obtained.

Next, the present invention will be explained using figures.

FIG. 1 is a process diagram showing one embodiment of the method of the present invention.

In Fig. 1, the polyester continuous yarn 1, which has just been spun at a spinning speed of about 3000 m/min, is in a relaxed state due to about 20% overfeed between rollers 2 and 3, and is heated to a dry heat temperature of 180°C. The heated heater 4 undergoes heat shrinkage treatment with a shrinkage rate of about 20%. Subsequently, the continuous yarn is cut between rollers 3 and 5 at a drafting ratio of 5 times to become short fibers, and then passed through a crimp device 6 and stored in a can 7 . The sliver 8 thus produced is thereafter supplied to a spinning process as appropriate to form a spun yarn.

The first feature of the woven or knitted fabric made from the spun yarn obtained by the method of the present invention is that it has a very flexible and bulky texture, is soft to the touch, and has excellent pilling properties. It means that you can get what you want.

Figure 2 is an example of a diagram showing the relationship between the amount of thermal shrinkage of continuous yarns due to heat treatment and the bulkiness of the fabric. The bulkiness (thickness mm) of the fabric was improved.

As is clear from FIG. 2, it can be seen that as the amount of heat shrinkage of the continuous yarn increases, the bulkiness of the fabric increases and the feel improves. It is also clear that even if the same heat treatment is applied, it will not be effective if the treatment is performed while stretching (that is, the negative direction of the horizontal axis in FIG. 2 means that the treatment is performed while stretching).

In addition, since the continuous yarn of the present invention is heat-treated in a relaxed state, the Young's modulus of the fiber is low, and fabrics made from spun yarn with this tension-cut can be flexible and soft to the touch, and at the same time The pilling properties of the woven or knitted fabric are also improved. Next, the second feature of the present invention is
This means that the hue of the woven or knitted fabric made of the spun yarn of the present invention is improved. FIG. 3 is an example of this, and is a diagram showing the relationship between the amount of thermal shrinkage (%) of continuous yarns due to heat treatment and the dyeability of the fabric. The horizontal axis of FIG. 3 represents the amount of heat shrinkage of the continuous yarn, and the vertical axis represents the dyeability (L value) of the fabric. As shown in FIG. 3, as the amount of heat shrinkage of the continuous yarn increases, the dyeability of the woven fabric improves, and the hue of the resulting woven or knitted fabric improves.

The dyeability (L value) referred to herein is evaluated by the lightness value (L value) measured by the density of the dyed material using a color difference meter.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing one embodiment of the method of the present invention, FIG. 2 is a diagram showing the relationship between the amount of heat shrinkage of continuous yarns due to heat treatment and the bulkiness of the fabric, and FIG. FIG. 2 is a diagram showing the relationship between the amount of thermal shrinkage of continuous yarns due to heat treatment and the dyeability of textiles.

Claims (1)

[Claims] 1. A spun yarn characterized in that a thermoplastic polymer is spun into a continuous yarn, the continuous yarn is heat treated in a relaxed state, and then tension-cutted into a yarn without substantially hot drawing. Manufacturing method.