KR100454498B1 - Manufacturing method of polyester microfiber - Google Patents

Abstract

The present invention relates to a method for producing a polyester ultrafine yarn, and more particularly, to a method for producing a polyester ultrafine yarn having a short fiber fineness of 0.15 denier or less using a melt spinning method.

It is an object of the present invention to provide a polyester ultrafine yarn having a short fiber fineness of 0.15 denier or less by using a melt spinning method, and to provide a method of preparing a polyester ultrafine yarn having high tensile strength and excellent radiation stability without causing entanglement.

According to the present invention, a step of preparing a molten polymer and discharging it through spinneret, cooling the molten polymer discharged through the spinneret to form an unstretched fiber, and stretching the unstretched fiber to polyester polyester microfiber In the melt spinning method consisting of the forming step, the molten polymer discharged through the spinneret in the step of forming the unstretched fiber is cooled to pass through a circular cooling cylinder into which cooling air of 10 ° C or less is introduced into an unstretched fiber. There is provided a method for producing a polyester ultra-fine yarn.

Description

Manufacturing method of polyester microfiber

The present invention relates to a method for producing a polyester ultrafine yarn, and more particularly, to a method for producing a polyester ultrafine yarn having a short fiber fineness of 0.15 denier or less using a melt spinning method.

In general, polyester filament yarn is made of various fineness and filament number, the smaller the fineness of the short fibers constituting the filament yarn, the softer the feel of the knitted fabric knitted with the filament yarn, the softer the suede-like feel, and the higher density is possible. There is an advantage. Microfibers with such a short fiber fineness are silk-like materials, artificial leather, breathable water repellent cloth, high density taffeta, dustproof clothing, filters, wiping cloths such as glasses mop, and weak fibers. It is widely used in fiber reinforcing agents, tough bags, floppy disk cases, as well as artificial blood vessels, artificial fur, nonwoven fabrics, paper flags, outer fabrics, underwear, and the like.

A conventional method for producing ultrafine fibers is disclosed in Japanese Patent Publication No. 48-25362, which releases unstretched fibers having a sea island cross section, and the natural nature of the island components. After stretching the unstretched fibers at the draw ratio in the stretch area, the sea component is dissolved and removed with a solvent to obtain the island component as ultrafine fibers. By stretching this again, a thin and high strength fiber can be obtained. However, this method is disadvantageous in the process because it requires an additional step of dissolving and removing the sea component with a solvent, and even after such solvent treatment, a small amount of sea component may remain on the fiber surface (water component), and This also has the drawback that the fiber surface is also violated to cause a decrease in strength.

In a similar manner, a mixture of two incompatible thermoplastic polymers is melt spun to obtain islands-in-the-sea fibers in which one of the polymers is finely dispersed. After stretching the island-in-the-sea fiber, the sea component is dissolved and removed by a solvent in the same manner as in Japanese Patent Publication No. 48-25362, and the island component is obtained as an ultrafine fiber. However, this method also has a disadvantage in the process of solvent treatment of the sea component, as in Japanese Patent Publication No. 48-25326, and even after such a solvent treatment, a small amount of sea component may remain on the fiber surface (waterborne component). In addition, there is a drawback that the fiber surface is also infringed by the solvent to cause a decrease in strength. In addition, there is a disadvantage in that long fibers cannot be obtained because the island components contained in the island-in-the-sea fibers are not continuous.

In addition, referring to the method disclosed in Japanese Patent Application Laid-open No. 51-554420, after stretching the polyester unstretched yarn composed of short fibers of 2-3 deniers without the orientation of the molecules, the orientation of the molecules is subsequently accompanied. The method of obtaining the polyester ultra-microfiber extended | stretched by the high draw ratio by carrying out the orientation drawing to do (neck extending | stretching) is disclosed. However, the fiber obtained by this method has extremely poor uniformity, cannot be used for medical purposes, and has a process problem in that a special stretching method is required.

In addition, Japanese Patent Application Laid-open No. 51-1303l7 discloses a fiber obtained by spinning a composite fiber composed of a plurality of thermoplastic polymers having incompatibility, and subsequently drawing the fiber obtained by knitting into a knitted fabric, and then dividing it by a mechanical or chemical method to obtain an ultrafine fiber. A method is disclosed. The fiber thus obtained is composed of a plurality of polymers, the dyeing process is complicated and dyeing contamination may occur.

Existing methods as described above are disadvantageous in terms of process compared to conventional melt spinning methods, and are also of poor quality. Despite such disadvantages, the above complicated method has been devised because the ultrafine fibers are not yet obtained by melt spinning as a single polymer. That is, it is because the ultrafine fiber whose short fiber fineness is 0.15 denier or less was not obtained by the melt spinning method of the normal polyester filament yarn.

A method for producing ultrafine fibers having a short fiber fineness reduced to about 0.15 denier by melt spinning is disclosed in Korean Patent Laid-Open Publication No. 96-37881. In this method, a heating body is installed directly under the spinneret, and the shape is circular. The cooling and cooling vents and outlets of the cooling air were alternately installed one or more times to provide ultrafine fibers of 0.35 to 0.15 denier. However, this method was not suitable because the short fiber fineness could not be lowered to 0.15 denier or less, and a separate cooling mechanism had to be provided.

It is an object of the present invention to provide a method for producing a polyester ultrafine yarn having a short fiber fineness of 0.15 denier or less using a melt spinning method.

Another object of the present invention is to provide a method for producing a polyester ultra-fine yarn having a high tensile strength and excellent radiation stability without entanglement.

According to the present invention, a step of preparing a molten polymer and discharging it through spinneret, cooling the molten polymer discharged through the spinneret to form an unstretched fiber, and stretching the unstretched fiber to polyester polyester microfiber In the melt spinning method consisting of the forming step, the molten polymer discharged through the spinneret in the step of forming the unstretched fiber is cooled to pass through a circular cooling cylinder into which cooling air of 10 ℃ or less is introduced into the unstretched fiber. There is provided a method for producing a polyester ultra-fine yarn.

MEANS TO SOLVE THE PROBLEM In the manufacture of the ultrafine fiber which single yarn fineness is 0.15 denier or less, it does not have the process disadvantage and the quality defect which appear in the conventional methods, and it stably improves the practically valuable ultrafine fiber by improving the existing melt spinning method. The method to obtain is presented.

It is already known that a superfine fiber of less than 0.15 denier of single fiber fineness cannot be obtained only by obtaining an unstretched fiber by an existing melt spinning method and orientation stretching it (for example, Japanese Chemical Fibers July, July, 1997, page 57). The reason is that in order to manufacture the ultra-fine fibers using the conventional melt spinning method, the discharge amount of the polymer per one ejection spinneret of the spinneret must be extremely small to spin the unstretched fibers, and the orientation stretching is performed at the highest draw ratio. When the amount of polymer discharge per spinneret of spinneret is gradually reduced to about 0.15g / min, trimming starts to occur just below the spinneret under normal spinning conditions, and the unfinished short fiber fineness after stretching is less than 0.3 denier. This is because continuous fibers cannot be obtained.

Therefore, in order to manufacture the ultra-fine fibers, a spinning method is required to produce fibers that can be spun without trimming and have a large maximum draw ratio of the obtained non-stretched continuous fibers even with a lower polymer discharge amount per spinneret discharge. The present invention has found that it is effective to quench the spinning fibers immediately after they are released from the spinneret and at the same time focus the spinning fibers at a relatively short distance from the spinneret.

Looking at the manufacturing method of the polyester ultra-fine yarn according to the present invention in detail.

In the melt spinning method of the present invention, the molten polymer is prepared, the molten polymer is measured and discharged through spinneret, and then the molten polymer discharged through the spinneret is cooled to form fibers to wind the fiber. Unstretched fibers are obtained, and the unstretched fibers are oriented and stretched to obtain ultrafine fibers having a fineness of 0.15 denier or less.

In more detail, the polyester polymer chip is kneaded and melted in the melt extruder and discharged from the spinneret via the metering pump. The molten polymer discharged through the spinneret is solidified and fiberized while passing through a cylindrical cooling cylinder, and cooling air of 10 ° C. or less is blown from the lower portion of the cooling cylinder to the upper portion of the circular cooling cylinder. At this time, when the temperature of the cooling air exceeds 10 ℃ the spinning fiber discharged through the spinneret is not solidified well to cause single yarn. In addition, the air flow rate of the cooling air is preferably 2.0 to 10.0Nm 3 / min, and in this case, when the airflow amount is less than 2.0Nm 3 / min, solidification capacity due to cooling is decreased, whereas single yarn occurs, whereas 10.0Nm 3 / min When the excess air volume is exceeded, the stability of the dead road is reduced, so that single yarns occur.

On the other hand, the spinning fiber discharged through the spinneret is concentrated through a guide at a position of about 10 to 150 cm below the spinneret while being cooled in the circular cooling cylinder. At this time, if the position where the spinning fiber is focused at a position within 10cm, the emission fibers are not solidified, so short fibers are easily fused or cut off by contact with guides. On the other hand, focusing at a location farther than 150 cm causes single cutting due to air resistance, so that continuous unstretched continuous fibers cannot be obtained. As such, by focusing all the short fibers at a point 10 to 150 cm below the spinneret, the air resistance is reduced, and the tension on the fiber is reduced, thereby reducing the fiber orientation. Therefore, the trimming due to air resistance can be prevented, and the maximum draw ratio of the unstretched fibers can be increased as compared with not connected at a point close to the spinneret, whereby a finer stretched fiber can be obtained.

As described above, the spinning fiber focused through the guide is oiled in the emulsion applying device to impart the binding, smoothness and antistatic property of the yarn, and then wound into the bobbin as an unstretched yarn.

The unstretched continuous fiber obtained by melt spinning in this way is usually oriented and stretched by a conventional stretching apparatus and put into practical use as a stretched fiber. That is, the unstretched continuous fibers are stretched while passing through a plurality of godet rollers to form ultra-fine fibers and wound up. In this invention, it is preferable to use well-known drawing apparatuses, such as an extending | stretching machine, an extending | stretching machine, and an extending | stretching combustor, for orientation stretching of an unstretched fiber.

In addition to polyesters, melt-spun fiber-forming polymers such as polyamides and polyolefins, which are thermoplastic polymers, may also be used to prepare ultrafine fibers using the method according to the present invention. Of course, small amounts of additives such as plasticizers, colorants, heat stabilizers, flame retardants, antistatic agents and the like can be added to these polymers.

In other words, in the present invention, instead of the flat cooling cylinder generally used in the solidification process of the molten polymer discharged through the spinneret, a circular cooling cylinder mainly used for manufacturing industrial polyester filament yarn is used. After the temperature is lowered to 10 ° C. or lower rather than room temperature, the molten polymer is solidified, and then the unstretched fibers are stably oriented to prepare microfibers stably.

In this way, the ultra-fine fibers obtained by the orientation stretching of the unstretched continuous fibers are free from woolen, entangled and the like, and can be sufficiently knitted in a conventional knitting process. In addition, the knitted fabric produced using the ultra-fine fibers have no staining stains, is flexible, has excellent feel, and gives a feeling close to natural suede.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

After drying the polyester resin having an intrinsic viscosity of 0.63, the spinneret was spun at a spinning temperature of 305 ° C. through a three-spin spinneret having a diameter of 0.1 mm and a number of spinnerets of 960 in a screw extrusion spinneret. At this time, the polyester resin was discharged at a discharge amount of 42.2g / min, spinning speed 2000m / min. The spinning fiber discharged through the spinneret is solidified while passing through a circular cooling cylinder. At this time, cooling air is introduced from the lower part of the circular cooling cylinder to the upper part, and the temperature is 5 ° C., and the air volume is 3.0 Nm 3 /. min. The spinning fiber solidified through the cooling process is concentrated at a position of 120 cm below the spinneret, and then subjected to an emulsion imparting device.

The non-drawn yarn obtained in this way was stretched through a first gourd roller having a temperature of 85 ° C. and a speed of 20 m / min, and a second gourd roller having a temperature of 120 ° C. and a speed of 3800 m / min.

The microfiber had a fineness of 97.2 denier, a tensile strength of 3.5 g / d, and an elongation at break of 38.1%.

Example 2

It carried out by the same method and conditions as Example 1 except that the air volume of the cooling air in the said circular cooling cylinder is 9.0Nm <3> / min. The resulting fineness of polyester ultrafine yarn was 96.8 denier, tensile strength was 3.4 g / d, and elongation at break was 37.2%.

Comparative Example 1

It carried out under the same conditions and methods as in Example 1 except that the air volume in the circular cooling cylinder was 1.0 Nm 3 / min. As a result, solidification of the filament was not made properly in the cooling tube, so that single yarns were generated and weaving was impossible.

Comparative Example 2

Except that the air volume of the cooling air in the circular cooling cylinder was 12.0Nm 3 / min was carried out under the same conditions and methods as in Example 1. As a result, due to too much air volume, single yarns occurred within 3 minutes after the thread was suspended, and normal sacrifice was impossible.

Comparative Example 3

The same conditions and methods as in Example 1 were conducted except that the temperature of the cooling air in the circular cooling cylinder was 15 ° C. As a result, solidification of the filament was not made properly in the cooling tube, so that single yarns were generated and weaving was impossible.

According to the present invention, instead of the flat cooling cylinder generally used in the solidification process of the molten polymer discharged through the spinneret, a circular cooling cylinder mainly used in the manufacture of industrial polyester filament yarn is used, and the temperature of the cooling air is By lowering the melted polymer to 10 ° C. or lower, not normal temperature, and then orientationally stretching the obtained unstretched fiber, a method for producing a polyester ultrafine yarn having a short fiber fineness of 0.15 denier or less is provided.

Thus prepared polyester microfiber has the advantage that the entanglement does not occur, the tensile strength is large and the radiation stability is excellent.

In addition, by concentrating all the short fibers at a point about 10 to 150 cm down from the spinneret, the air resistance is reduced, and the tension applied to the fibers is reduced, thereby reducing the fiber orientation. Therefore, the trimming due to air resistance can be prevented, and the maximum draw ratio of the unstretched fibers can be increased as compared with not connected at a point close to the spinneret, whereby a finer stretched fiber can be obtained.

Claims (4)

Preparing a molten polymer and discharging it through a spinneret; and cooling the molten polymer discharged through the spinneret by the discharged molten polymer to form an unstretched fiber, and stretching the unstretched fiber to polyester In the melt spinning method consisting of forming a micro-fine yarn, And wherein the molten polymer discharged through the spinneret in the step of forming the unstretched fiber is cooled while passing through a circular cooling cylinder into which cooling air of 10 ° C. or less is introduced, thereby forming an unstretched fiber. The method of claim 1, wherein the air flow rate of the cooling air in the step of forming the unstretched fiber is 2.0 to 10.0 Nm 3 / min. The method of claim 1, wherein the microfiber short fiber fineness is 0.15 denier or less. The method of claim 1, wherein the position where the spinning fibers discharged through the spinneret are focused is 10 to 150 cm.