KR100464786B1 - Method for producing polyester fiber - Google Patents

Abstract

The present invention is a sectional cross-section yarn having a very small and fine pores on the surface of the polyester fiber and excellent molecular orientation in the fiber axis direction, a portion of the fiber is fibrillated in the fiber axis direction during alkali reduction processing polyester fiber The technical configuration of the present invention relates to an inorganic polymer of titanium oxide or silica oxide for promoting fibrillation in an intermediate polymer formed by carrying out a polycondensation reaction in the production of polyester produced by diol and dicarboxylic acid or ester reaction thereof. 1.0 ~ 4.0% by weight of particles are used to obtain the polymerized product and to spin it, using a specially designed release cross-section using a specially designed spinneret to increase the release ratio of the slits, thereby improving molecular orientation and fibrillation during post-processing. Increasing the amount of emulsion adhesion of the produced fiber to 0.7 ~ 3.0% A polyester fiber is produced that is excellent and does not cause staining spots.

Description

Method for producing polyester fiber

The present invention relates to a method for producing a polyester fiber that can be easily expressed through the fibrillation of the polyester fiber, such as comfort and soft touch to the human body that is characteristically expressed in natural fibers or recycled fibers.

Fibrillation of fibers means that one fibrous fiber is separated into fine fibrils of several strands in the post-processing process of the knitted fabric. Not only do they differ fundamentally in their effectiveness, but they also differentiate their use. In the aspect of making the fiber extremely thin, it is similar to the ultrafine fiber, but the manufacturing technology of the fibrillated fiber is not the process of spinning the yarn from the spinning process, but instead of the original single strand fiber in the post-treatment process of the knitted fabric. It is very different from the method of manufacturing microfibers. When this effect is expressed on the surface of the knitted fabric, the shiny metallic luster and stiff feel peculiar to synthetic fibers are eliminated. Instead, the faint gray gloss and soft feel are expressed. The effect of the fiber can also be expressed on the surface of the polyester knitted fabric. More advantageously, fibrillation is expressed in the general dyeing process without a separate process for producing such effects in post-processing, which is a great help in improving process performance and quality in the textile industry.

However, it has been evaluated that the expression of fibrillation is almost impossible in the conventional polyester fiber for clothing, and it is known that it can be expressed only by some acrylic fibers or industrial nonwoven fabrics. As a result of various studies by the researchers, fibrillation can be expressed in various forms in polyester fibers, and the core technology of manufacturing fibrillated fibers is that inorganic particles are eluted to a sufficient level by alkali reduction processing. It has also been found to be in the manufacture of hollow fibers or sectioned yarn with high molecular orientation.

However, the general release cross-section yarn has excellent dry touch and absorption quick-drying, while the initial elastic modulus and the second moment value are very high compared to the raw fiber, and because the elasticity is low, the fabric feels hard and stiff. There is a problem that falls significantly. In order to compensate for this, it is possible to perform stronger alkali reduction in high-order processing of fabrics or to manufacture a special shaped release cross-section yarn, but it is difficult to give uniform emulsion during spinning as the release of cross-section increases. Since yarn may be manufactured or the elongation at the woven fabric may be lowered, there are problems such as limited development in various applications.

Looking at the conventional techniques for this fibrillation, Japanese Unexamined Patent Application Publication No. Hei 1-298210 discloses that in manufacturing direct-stretching hollow fibers having different anisotropy in the fiber axis direction, internal hollow parts and external uneven parts are formed. A technique is known in which fibrillation is expressed only when purifying the hollow fiber by lengthening the connecting part to be connected, and according to JP 57-82543, spinneret for expressing dry feeling and flexibility on the fabric. It is shown that when the V-shaped or U-shaped cross section is designed, excellent physical properties are expressed in the knitted fabric, and the fibrillation is expressed on the fiber surface only when the alkali loss is excessively advanced. In addition, Korean Patent Laid-Open Publication No. 97-702941 includes a core portion and a plurality of fin portions protruding radially from the core portion in the longitudinal direction of the core portion, and at least a part of the slits when each slits are subjected to alkali reduction processing. Disclosed is a manufacturing technology of a polyester filament yarn in which a core is separated from a core to form fibrils.

The problem of the prior art in the production of fibrillated fibers is that when the shape of the spinneret for the expression of fibrillation is excessively deformed from the circular shape, the elongation properties are greatly reduced or eluted at the time of alkali reduction compared to the circular fiber. If the amount of the modifier is large, the spinning workability is drastically deteriorated due to problems such as a sudden rise in the spinning pressure. In addition, in order to increase the fibrillation and increase the release ratio of the slits in order to increase the fibrillation effect in the woven fabric, the uniform emulsion impartment and the appropriate emulsion pick-up rate, which are essential in the spinning process, become poor. There is a problem that one yarn is manufactured.

From this point of view, it is considered that the hollow fiber or the sectional cross-section yarn is more advantageous to the fabrication of the fibrillable fiber than the general circular fiber. The study found that the slits were well fibrillated by the tension applied during post-processing. However, when the slitting part is processed longer than a certain range, many problems such as the elongation of the yarn and the deterioration of the radioworkability due to the uneven emulsion are exerted. In addition to the expression of berylation, the result is excellent in the radioworkability. And in order to express a sufficient level of fibrillation at the time of alkali reduction, it is necessary to somewhat weaken the portion of the side slitting portion and the central core portion in which the fibrillation is expressed.

As a result of research on various types of spinnerets, the side slits have 2 to 4 slits for the central core, and the cross section of the side slits has a general circular cross section. have. In particular, it was found that the diameter ratio and the contact distance of the central core portion and the side slitting portion should be set within a certain range so that fibrillation can be expressed to a satisfactory level during post-processing. By setting the spinneret specifications to the level that satisfies the above conditions, the generation of static electricity or uneven stretching due to the uneven emulsion during polyester filament spinning was prevented, especially the fiber with excellent uniformity and excellent fibril expression by post-processing It was possible to prepare.

In order to increase the fibrillation expression during alkali reduction processing, the distance between the central core portion and the side slitting portion of the spinneret should be at least within the range of 0.05 to 0.15 mm. Although very good in shape, the fibrillation is rapidly decreased, and if it is 0.15 mm or more, there is a problem in that the adhesion of the polymer is not made or the radiation workability is extremely poor due to trimming and fine thread generation. In addition, in order to apply uniform emulsion, it is necessary to set the diameter ratio of the center core part and the side slitting part to 0.3 to 1.0 range. In this case, when the ratio of the core part and the slitting part is set to 1.0 or more, the flowability of the polymer is the side pin part. When the ratio is set to 0,3 or less, there is a high possibility of fine sanding or trimming due to poor polymer discharge from the side fins, and especially a uniform emulsion. The provision of becomes very disadvantageous, and the production of the fibrillated fiber targeted in this invention becomes impossible. In addition, the amount of oil adhered to the final yarn should be in the range of 0.7% to 3.0% by weight of the filament. If the oil deposition amount is less than 0.7%, problems such as static electricity generation or concentration failure between the multifilaments may occur due to insufficient emulsification, and if it is more than 3.0%, uneven adhesion or fusion on the surface of the filament will occur. This happens and the nonuniformity of the yarn is rapidly increased.

In addition, it is important to add the amount of titanium oxide or silica oxide to be added in the range of 1.0 to 4.0% by weight in order to increase the expression of fibrillation during alkali reduction processing. If less than 1.0% is added, the fibrillation does not easily occur when reducing the alkali in the fabric, and if it is added more than 4.0% by weight, spinning occurs due to aggregation or gelation of silica or titanium particles. The pressure rises rapidly, causing frequent trimming or extremely poor workability.

As a result of conducting a research review on the above various conditions, it was possible to manufacture the fibrillated fiber pursued by the present invention. Hereinafter, the present invention will be described in detail. The polyester used was added 2.5 wt% of the phosphate compound as a heat stabilizer at the end of the ester reaction or at the beginning of the polycondensation reaction as a heat stabilizer in preparing the polyester produced by the diol and dicarboxylic acid or its ester reaction. The polymerization product was formed by adding 1.0 to 4.0% by weight of inorganic particles of titanium oxide or silica oxide having a size of 20 to 200 nm to the intermediate polymer formed by performing a polycondensation reaction at ℃. Thereafter, the polymerization product was preliminarily dried at 140 ° C. for 2 hours and main drying at 160 ° C. for 14 hours to prepare fibers at a spinning speed of 5,000 to 7,000 m / min. At this time, the spinning temperature was in the range of 295 ± 2 ℃, and especially the temperature in the lower part of the spinneret was kept constant to prevent the change in the properties of the yarn, the degree of fibrillation, and the texture of the knitted fabric due to the change in the lower part of the spinneret. It was. The knitted fabric made of the yarn was subjected to weight loss processing in a 5% aqueous alkali solution for 20 minutes, and finally, the degree of fibril expression and the texture of the knitted fabric were evaluated.

Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples.

Example 1

Polyethylene terephthalate (2.5% by weight of titanium oxide and silica oxide as quencher) = 0.655) was melted and discharged at a spinning temperature of 295 ° C. through a release cross-section mold 1 having a cross-sectional structure as shown in FIG. 2 having four side slits and a center core part having a distance of 0.1 mm. After cooling and solidifying the multifilament using the cooling air (2) discharged at a rate of / min, the emulsification (4) and air entanglement (5) at the tip of the first roller (6) is carried out, and maintained at room temperature After winding 0.5 times in the first roller (6) and the second roller (7) to be wound in the final winding machine (9).

At this time, as the spinneret used, as shown in FIG. 2, a heterogeneous cross-section tool having a diameter ratio of 0.5 to the center core portion and the side slits was used, and tension was uniformly applied to each filament for stable spinning workability and uniform emulsification. It wound up in the range of 5,000-7,000 m / min of spinning speed, maintaining. After that, a multi-filament was used to prepare a knitted fabric, and the obtained knitted fabric was subjected to weight loss processing in 5% alkaline aqueous solution to evaluate the touch and fibril expression after weight loss.

Fibril expression in cross-sectional shape and alkali-reduced fibers was measured using SEM (Scanning Electron Microscopy). At this time, if the expression level of fibrillation is 100-10000 / cm2, it is very good (◎), if it is 10-100 / cm2, it is excellent (○), and if it is less than 10 / cm2, it is not good (×). As for the evaluation of the fabric, the sensory evaluation was performed on soft touch, resilience and color development. A schematic process diagram of the spinning apparatus used in this invention is shown in FIG.

Example 2

A polyester multifilament was prepared under the same conditions as in Example 1, except that the spinnerets used had a distance of 0.05 and 0.15 mm from the center core to the side slits and a diameter ratio of 0.50. The fibers were prepared at min.

Example 3

A polyester multifilament was prepared under the same conditions as in Example 1, except that the spinneret used had a distance of 0.10 mm between the center core and the side slits and a diameter ratio of 0.30 and 1.0, respectively, with a spinning speed of 6,000 m. Fibers were prepared at / min.

Example 4

A polyester multifilament was prepared under the same conditions as in Example 1, except that the spinning speed was adjusted at 6,000 m / min while adjusting the gear pump number of the emulsion applying device so that the oil deposition rate of the yarn was 0.7% and 3.0%, respectively. Spinning.

Example 5

A polyester multifilament was prepared under the same conditions as in Example 1 except that the polyester polymer used was spun using 1.0 wt% and 3.5 wt% of silica oxide or titanium oxide, respectively, based on the amount of polymer. It was.

The physical property evaluation results of the polyester fibers obtained in Examples 1 to 5 are shown in Table 1.

Comparative Example 1

Polyester multifilament was prepared under the same conditions as in Example 1, except that the fibers were prepared at spinning speeds of 4,000 m / min and 8,000 m / min, respectively, and then developed into woven fabrics. The touch was evaluated.

Comparative Example 2

The polyester multifilament was manufactured under the same conditions as in Example 1 except that the spinnerets used were 0.20 mm apart from the distance between the center core and the side pins, and the diameter ratio was 0.50. The fibers were produced at a speed of 6,000 m / min.

Comparative Example 3

A polyester multifilament was prepared under the same conditions as in Example 1 except that the spinnerets used were 0.10 mm in distance between the center core and side slits, and their diameter ratios were 0.20 and 1.25, respectively. Fibers were prepared at / min.

Comparative Example 4

A polyester multifilament was prepared under the same conditions as in Example 1, except that the gear pump rotation speed of the emulsion applying device was adjusted so that the oil adhesion rate of the manufactured yarn was 0.5% and 3.5% at a spinning speed of 6,000 m / min. Spinning.

Comparative Example 5

A polyester multifilament was prepared under the same conditions as in Example 1 except that the polyester polymer was used in which no silica oxide or titanium oxide was added, 0.5% charged, and 4.5% added, respectively, based on the amount of polymer. Was used to spin at a spinning speed of 6,000 m / min.

Comparative Example 6

Polyester multifilament was prepared under the same conditions as in Example 1, except that the spinneret used was made of yarn using a cross-sectional shape of the side slitting portion of the central core portion as shown in FIG. .

Table 2 shows the results of evaluation of physical properties of the polyester fibers according to Comparative Examples 1 to 6.

According to the present invention, a single strand of polyester fiber is separated into tens to thousands of thin fibrils by a post-processing process, and in particular, the fibrillation in the fabric state makes the fiber comfortable and soft to the human body seen in natural fibers. You will feel the effect from.

1 is a schematic process diagram of a spinning apparatus used in the present invention,

Figure 2 is a cross-sectional view showing the cross-sectional shape of the mold release cross section used in the present invention,

3 is a cross-sectional view showing the cross-sectional shape of the release cross section of the mold used in the comparative example of the present invention;

4 is a perspective view showing the expression state of fibrils after weight loss processing,

5 is a photograph of the surface of the fabric is expressed fibrillation.

<Description of Symbols for Main Parts of Drawings>

1: detention 2: cooling air outlet

4: emulsification 5: air jammer

6: 1st roller 7: 2nd roller

9: winder

Claims (3)

In preparing a polyester release section yarn produced by diol and dicarboxylic acid or ester reaction thereof, 1.0 to 4.0% by weight of inorganic particles of titanium oxide or silica oxide was added to the intermediate polymer formed by the polycondensation reaction to obtain a polymerization product, and a spinning cross-section using a spinneret using a spinneret was used to obtain a polymerization product. A method of producing a polyester fiber, characterized in that the emulsion deposition amount of the fiber produced by spinning at high speed in the range of 5000 ~ 7000m / min so that 0.7 ~ 3.0%. The method according to claim 1, A method for producing a polyester fiber, comprising a side slitting portion having 2 to 4 slits, and having a circular cross section of the side slitting portion, in the central core portion of the spinneret for forming a cross section. The method according to claim 1 or 2, Method for producing a polyester fiber characterized in that the contact distance of the central core portion and the side slitting portion of the spinneret for release cross section is in the range of 0.05 to 0.15mm, and the ratio of diameter (RS / RC) is in the range of 0.3 to 1.0