KR20020004201A - A process of preparing for the polyester yarn - Google Patents

Abstract

PURPOSE: A polyester fiber and a manufacturing method thereof are provided, which is characterized by improving productivity, increasing processability of drawing and false-twisting, improving touch and bulkiness, and producing partly oriented yarn of polyester by retarding spinning-crystallization though spinning is done at over 4000m/min. of winding speed. CONSTITUTION: The polyester fiber is obtained by a process containing the steps of: supplying 95-99.5wt.% of polyester polymer and 0.5-5.0wt.% of crystal orientation inhibitor from each supplying device to a pressing-melting device(1); melting and mixing to produce melted mixture; supplying the melted mixture to a spinning device with a booster pump(3); and then spinning and winding at over 4000m/min. of velocity.

Description

Process for preparing polyester fiber {A process of preparing for the polyester yarn}

The present invention relates to a method for producing a polyester fiber that can effectively delay the phenomenon that the crystallization on the radiation sharply increases when the high-speed spinning of the polyester fiber.

When spinning a polyester polymer at a high speed of more than 4,000m / min, the phenomenon of "Spinning Crystallinity" occurs due to the rapid increase in the radial tension, which causes severe process instability factors such as cutting and moor. The sex is significantly lowered. As a result, when spinning the polyester fiber, there is a limit of spinning speed, and currently the mass production of polyester partial alignment yarns is usually produced at spinning speeds of 3,500 to 4,000 m / min.

At the spinning speed of 4,000m / min as the critical point, the increase in molecular orientation increases without increasing the crystallinity, but when the spinning speed exceeds 4,000m / min, the molecular orientation and crystallinity increase simultaneously. Therefore, as the spinning speed increases, the crystallinity increases rapidly with the increase of the radial tension and the alignment crystallization accordingly. As the spinning speed increases, the density and birefringence also increase. Ziabicki and H. Kawai Edited, 'High Speed Fiber Spinning', John Wiley & Sons, New York, 1985].

Until now, the process of delaying the rapid increase of the crystallization on the radiation by increasing the spinning speed in the polyester fiber production process overcomes the existing limit spinning speed and spins the polyester partial alignment yarn at a high speed of 4,000 m / min or more. Much research has been conducted on. Known methods to date can be roughly classified into first, through the modification of the raw polymer (copolymerization, molecular chain crosslinking, etc.) and second, by mixing the polymer material.

As a first method, EP 0 263 020 and US Pat. No. 4,518,744 add compounds pentaerythrite, trimethylropropane, melitic acid and trimellitic acid, which have side chains to the molecular chain, before or after transesterification or polymerization. US Patent 4,966,740 proposes a method for adding tetraethyl silicate before or after the transesterification reaction, US Patent 4,092,299 proposes a molecular chain crosslinking method using a tetrafunctional material have. However, the first methods must specifically select the polymerization conditions, and the workability in the draw combustion process is lowered. In particular, the high cutting rate in the combustion process causes a problem of difficult combustion.

As a second method, US Pat. No. 4,609,710 discloses a method of mixing polystyrene, polyamide, polymethylmethacrylate, or the like as a molecular alignment regulator during or after the polymerization of a polyester. In addition, a method of reducing the radiation orientation by adding a small amount of liquid crystal polymer material, polyethylene, polyethylene glycol, etc. in the conventional polyester polymerization is known. Appl. Polym. Sci., 31 , 2753 1986)]

In this case, the flowability of the polymer melt in the spinning process is drastically changed, which greatly affects the spinning characteristics, in particular, the spinning speed, thereby lowering the spun orientation. However, the method is difficult to spin stably due to the problem of uniformly mixing the added polymer, and the mixed polymer is moved to the fiber surface in the drawing and burning process to inhibit the workability, the occurrence of wool and fine dye stains Occurrence is a cause of deterioration of the final false twist quality.

The present invention is to provide a method for producing a polyester fiber that can effectively delay the phenomenon of the rapid increase in crystallization on the radiation when spinning the polyester fiber at a winding speed of 4,000m / min or more. In addition, the present invention can efficiently melt and mix the polyester polymer and the crystal orientation suppressor with a simple device, and 4,000 polyester partial orientation yarns that can prevent the crystal orientation inhibitor from moving to the fiber surface to reduce yarn quality. It is intended to provide a method which can be produced at a winding speed of m / min or more.

1 is a schematic cross-sectional view of a pressure melting machine used in the present invention.

※ Explanation of main parts in drawings

1: pressure melting machine body 2: stirrer

3: booster pump 4: discharge tube

The method for producing the polyester fiber of the present invention for achieving such a problem, in the production of polyester fibers by melt-spun polyester polymer, 95.0 to 99.5% by weight of the polyester polymer in the melter and 0.5 ~ crystal orientation suppressor After supplying 5.0% by weight through a separate feeder, melt and mix them to prepare a molten mixture, and then supply the molten mixture uniformly to the spinning apparatus using a booster pump to continuously supply a rate of 4,000 m / min or more. It is characterized by spinning, winding.

Hereinafter, the present invention will be described in detail.

First, the present invention supplies 95.0 to 99.5 wt% of the polyester polymer and 0.5 to 5.0 wt% of the crystal orientation suppressor of the thermoplastic resin to the pressure melter as shown in FIG. 1 through a separate feeder, and then melts / mixes them to melt the mixture. To prepare. As the crystal orientation suppressor, polymethyl methacrylate resin, polystyrene resin, or methyl methacrylate-styrene copolymer resin is used.

The glass transition temperature (Tg) of the crystal orientation suppressor is 100 ° C. or more. The reason is to maintain the difference in the solidification behavior of the polyester polymer having a glass transition temperature (Tg) of 80 ° C. on the radiation and the crystallization inhibitor, thereby suppressing the crystal orientation behavior of the polyester polymer.

If the glass transition temperature (Tg) of the crystallization inhibitor is less than 100 ℃, the difference in the solidification behavior between the polyester polymer and the crystallization inhibitor is small, it is difficult to effectively suppress the crystal orientation behavior of the polyester polymer on the radiation. As a result, the winding speed cannot be made higher than 4,000 m / min.

Due to the attractive force between the aromatic ring included in the crystallization inhibitor and the aromatic ring included in the polyester molecule, it is possible to more effectively inhibit the orientation crystallization occurring during the spinning and stretching process. It is well known that an aromatic ring is composed of double bonds between constituent carbon atoms, and therefore, an attractive force exists between adjacent aromatic rings.

In addition, the aromatic part is a rigid part inside the molecular chain, while the aliphatic part means a flexible part. Therefore, the presence of an appropriate aromatic part can maintain the mechanical properties of the polymer chain, a crystallization inhibitor, thereby minimizing the loss of mechanical properties, such as a decrease in strength by the crystallization inhibitor fibrils distributed in the polyester. .

From this point of view, by using the crystallization inhibitor of the present invention, it is possible to maintain a similar level of physical properties, particularly strength, to the polyester partial-orientated yarn prepared by the general method.

The amount of the crystallization inhibitor added is 0.5 to 5.0% by weight based on the weight of the entire polymer (polyester polymer + crystallization inhibitor). If the added amount is less than 0.5% by weight, the effect of suppressing radiocrystallization is insignificant, and when the added amount is more than 5.0% by weight, the stretching and flammability processability deteriorate.

The pressure melter 1 used in the present invention has a shape as shown in FIG. 1, and a stirrer 2 is installed inside the pressure melter 1, and a booster pump 3 is disposed at a lower end of the melt melt discharged. It is installed.

In the pressure melting machine (1), the polyester polymer and the crystallization inhibitor are melted and mixed for 10 minutes. At this time, the temperature of the pressure melting machine 1 is preferably set to about 300 ℃ level. The stirrer speed of the pressure melter (the tip of the stirrer blade) is preferably 5 to 50 cm per second. If the shear force is too weak or the melt / mix time is too short, the polyester polymer and the crystal orientation suppressor are not melted / mixed uniformly, making high-speed spinning difficult and the quality of the yarn deteriorated. On the other hand, if the shear force is too strong or the melting / mixing time is too long, there is a high possibility that the polymer properties change.

Next, the molten mixture is uniformly supplied to the spinning apparatus using the booster pump 3 to spin and wind at a speed of 4,000 m / min or more. The molten mixture is quantitatively supplied to the spinning apparatus through the discharge pipe 4 by the booster pump 3.

Thus, the elongation at break of the partial oriented yarn wound at a speed of 4,000 m or more per minute is 120% or more. When the elongation is more than 120% crimp frequency (Crimp Frequency) is high, the crimp quality can be obtained good twisted yarn, it is possible to secure excellent flammability workability. Otherwise, it is difficult to perform high-speed operation more than 800 meters per minute in the simultaneous drawing and burning process, and it is difficult to obtain the same twisted yarn with the same physical properties as in the case of the simultaneous drawing and burning of the unstretched yarn spun at ordinary 3,000 to 3,500 meters per minute. It is difficult to secure the stability of the work by obtaining the combustible yarn with reduced varnish (Crimp Liveliness).

In the present invention, it is preferable to maintain the shear rate in the spinneret during spinning at 7,000 to 15,000 per second. The shear rate in the spinneret during spinning is the dominant factor that determines the radial distribution of the crystallization suppressor distributed inside the spun yarn.

If the shear rate is low, the degree of orientation of the crystallization inhibitor in the fiber axis direction is lowered, which may cause a problem that the effect of suppressing the orientation crystallization of the polyester fiber is reduced. On the other hand, if the shear rate is too high, The problem that the distribution is concentrated on the surface portion of the fiber occurs, which may cause a problem of lowering the strength.

Therefore, if the shear rate in the spinneret is maintained within the range of 7,000 or more and 15,000 or less per second, the effect of suppressing the orientation crystallization of the polyester fiber is sufficiently exerted, and the distribution of the crystallization suppressor in the radial direction of the fiber is appropriately maintained and partially aligned. The strength of the yarn and the false twisted yarn can be maintained properly.

The polyester fiber of the present invention prepared as described above is 95 to 99.5% by weight of the main polyester and the polymethyl methacrylate resin, polystyrene resin or methyl methacrylate-styrene copolymer resin 0.5 Consists of ~ 5.0% by weight, the elongation at break is more than 120%.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Example 1

19.1% by weight of polyethylene terephthalate having an intrinsic viscosity of 0.64 and 0.9% by weight of methyl methacrylate / styrene copolymer having a glass transition temperature of 105 ° C. After feeding to the feeder, they are melted and mixed for 3 minutes to produce a molten mixture.

Subsequently, the molten mixture was uniformly supplied to the spinning apparatus through the discharge pipe 4 to the booster pump 3, and the 36 discharge holes were spun through the punched spinneret, and the cooling process at 22 ° C was performed at 0.5 mm per second. The polyester partial alignment yarn was manufactured by sending out by speed, cooling, solidifying, and winding up. At this time, the shear rate in the spinneret was 9,000 per second and the winding speed was 4,200 m / min.

The twisted yarn was manufactured using the Murada 33H (manufactured by Japan Murada Co., Ltd.) draw-synchronous combustor. The burning rate was 850 m / min, the drawing ratio was 1.671 times, the temperature of the first heating plate was 200 ° C., the angle between the nip belts was 105 degrees, and the speed ratio was 1.5.

The final false twisted yarn was circular knitted using a circular knitting machine, and then dyed at 130 ° C. for 60 minutes using a disperse dye, and then dyeing quality of the plaque was examined. Table 2 shows the results of evaluating the fairness of spinning and combustibility and the properties of partially aligned yarns and combustible yarns.

Example 2 to Example 6 and Comparative Example 1 to Comparative Example 2

The polyester partial alignment yarn, false twist yarn and circular knitted fabric were manufactured under the same process and conditions as in Example 1 except that the resin type, glass transition temperature, mixing weight%, and winding speed of the crystallization inhibitor were changed as shown in Table 1. It was. Table 2 shows the results of evaluating the fairness of spinning and combustibility and the properties of partially aligned yarns and combustible yarns.

Polyester partial alignment yarn manufacturing conditions division Pressure melter processing time (minutes) Crystallization Inhibitor Properties Winding speed (m / min) Resin type Glass transition temperature (℃) Addition amount (% by weight) Example 1 3 Methyl methacrylate-styrene copolymer 105 0.9 4,200 Example 2 4 Methyl methacrylate-styrene copolymer 105 2.5 4,500 Example 3 5 Polymethyl methacrylate 106 1.5 4,800 Example 4 3 Polymethyl methacrylate 106 3.5 4,300 Example 5 4 polystyrene 107 2.9 4,300 Example 6 5 polystyrene 107 4.0 4,100 Comparative Example 1 15 - - - 4,500 Comparative Example 2 2 Polymethyl methacrylate 106 0.1 4,200

Workability and Yarn Property Evaluation Results division Radiation workability Partial Alignment Elongation (%) Combustible Workability Primp Quality Platter Cream Rigidity (%) Example 1 Good 125 Good 41 none Example 2 Good 132 Good 38 none Example 3 Good 138 Good 39 none Example 4 Good 143 Good 42 none Example 5 Good 147 Good 44 none Example 6 Good 123 Good 43 none Comparative Example 1 Bad 83 Bad 28 has exist Comparative Example 2 Somewhat defective 110 Bad 29 has exist

The present invention can effectively delay the "radiation crystallization" in which the crystallization on the radiation is rapidly increased during high-speed radiation to produce a polyester partial alignment yarn at a winding speed of 4,000m / min or more. As a result, productivity is improved. In addition, the present invention can be homogeneously mixed with the polyester polymer and the crystal orientation inhibitor which is a crystal orientation inhibitor with a simple device, the device is simple and excellent stretching and flammability processability. In addition, the present invention can effectively prevent the phenomenon that the crystal orientation inhibitor is moved to the yarn surface to reduce the yarn quality.

Claims (3)

In manufacturing polyester fiber by melt spinning the polyester polymer, 95.0 to 99.5 wt% of the polyester polymer and 0.5 to 5.0 wt% of the crystal orientation suppressor are respectively supplied to the pressure melter through a separate feeder, and then melted and mixed. To prepare a molten mixture, and then uniformly quantitatively supply the molten mixture to a spinning apparatus using a booster pump to spin and wind continuously at a rate of 4,000 m / min or more. The method for producing a polyester fiber according to claim 1, wherein the crystallization inhibitor is a polymethyl methacrylate resin, a polystyrene resin or a methyl methacrylate-styrene copolymer resin. The method for producing a polyester fiber according to claim 1, wherein the crystallization inhibitor has a glass transition temperature of 100 ° C or higher.