KR100601300B1 - A polyester yarn, and a process of preparing for the same - Google Patents

Abstract

In the present invention, when the polyester fiber is produced by high-speed spinning, it is possible to effectively delay the phenomenon in which the crystallization on the radiation increases rapidly (radiation crystallization), and thus to fine-spun the polyester partial alignment yarn of fine fineness (4,000 m or more per minute). It is characterized in that the manufacture. In the present invention, 0.5 to 5.0% by weight of a crystal orientation inhibitor during the conventional polyester polymerization is added thereto, and the mixture is uniformly mixed, and then discharged into a mold, followed by cooling and solidification under the condition of the following formula (I), and continuously 4,000 Spinning is carried out so that single fiber fineness may be 1.0 denier or less at a winding speed of m / min or more.

                        -Below-

〈 1.2 (I)0.9

〈1.2 (I)

Wherein X is the multifilament average cooling rate gradient of the present invention, and Y is the multifilament average cooling rate gradient under the condition that the winding speed is 3,200 m / min and no crystal orientation inhibitor is added.

   The present invention improves productivity by manufacturing polyester partial alignment yarn at high speed, and improves processability such as spinning and stretching flammability, and can also improve quality of final yarn.

Polyester, High Speed Spinning, Partial Alignment Yarn, Crystal Alignment Inhibitor, Stationary Kneader

Description

Polyester fiber and its manufacturing method {A polyester yarn, and a process of preparing for the same}             

The present invention relates to a polyester fiber (High multi polyester yarn) and a method for producing the same that can effectively delay the phenomenon of the rapid increase in crystallization on the radiation when spinning 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, polymethyl methacrylate, or the like as a molecular alignment regulator during or after polymerization. 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. '' Orientation Supression in Fibers Spun from Polymer Melt Blends' (H. Brody, J of 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 is excellent in workability of spinning, stretching, and flammability, the crystal orientation inhibitor can be prevented from moving to the fiber surface to reduce the yarn quality, while maintaining the yarn elongation at 120% or more, more than 4,000m / min An object of the present invention is to provide a method for producing a polyester partial alignment yarn at a winding speed.

The present invention relates to a method for producing a polyester fiber that can effectively delay the spinning crystallization phenomenon at the time of high-speed spinning the polyester fiber, excellent in stretching and flammability processability.

More specifically, the present invention in the manufacture of polyester fibers by melt spinning the polyester polymer, 0.5 to 5.0% by weight of the crystal orientation inhibitor uniformly mixed with the conventional polyester polymer in the molten state, and then discharged through the detention After cooling and solidifying with a cooling wind so that the average cooling rate gradient of the multifilament satisfies the condition of the following formula (I), it is continuously radiated to have a single fiber fineness of 1.0 denier or less at a winding speed of 4,000 m / min or more. The manufacturing method of the polyester fiber characterized by the above-mentioned.

                       -Below-

〈 1.2 (I)0.9

〈1.2 (I)

Wherein X is the multifilament average cooling rate gradient of the present invention, and Y is the multifilament average cooling rate gradient under the condition that the winding speed is 3,200 m / min and no crystal orientation inhibitor is added.

The present invention also relates to a polyester fiber composed of 95 to 99.5% by weight of the conventional polyester as a main component and 0.5 to 5.0% by weight of the crystal orientation suppressor, having a single yarn fineness of 1.0 denier or less, and an elongation at break of 120% or more.                     

Hereinafter, the present invention will be described in detail.

First, the present invention, when melt spinning the polyester polymer, 0.5 to 5.0% by weight of the crystal orientation suppressor of the thermoplastic resin is mixed with the conventional polyester polymer in the molten state. 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.

In the present invention, the mixing of the polyester polymer and the crystallization inhibitor is first performed by supplying the polyester chip to the extruder and melting the same, followed by supplying the molten polyester to the two-stage biaxial screw extruder and simultaneously crystallizing the same. An orientation inhibitor chip is supplied to melt and mix them. More preferably, the melt mixed in the two-stage twin screw extruder is continuously kneaded with a stationary kneader.

Meanwhile, the polyester polymer chip and the crystal orientation suppressor chip may be simultaneously supplied to the extruder to melt and mix them, and then the melt may be continuously kneaded with a stationary kneader.

The stationary kneader serves to make the crystal orientation suppressor distribution more uniform in the melt. In the case of the present invention, since more uniform kneading is required, it is preferable to pass a stationary kneader of 20 stages or more. In other words, kneading of 1 million (2 ²⁰ ) times or more enables uniform distribution of crystallization inhibitors, and is preferable to prevent salt spots in the false twisted state, which is a final product.

Otherwise, if the stationary kneader of less than 20 stages is adopted, deterioration of the quality may occur due to the occurrence of fine salt spots in the twisted yarn state. There is a possibility of becoming difficult.

As described above, the conventional polyester polymer and the crystal orientation suppressor are uniformly melted and mixed, and then cooled and solidified with a cooling wind so that the average cooling rate gradient of the multifilament satisfies the above formula (I), followed by continuous 4,000 m. Spinning is performed so that single yarn (short fiber) fineness is 1.0 denier or less at a winding speed of / min or more. The take-up speed increases productivity by 40% at least 4,000 meters per minute. Winding speeds of less than 4,000m / min have little productivity gains, so there is no economic benefit in terms of return on facility investment.

In addition, the elongation at break of the partial oriented yarn wound at a speed of 4,000 m or more per minute was 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 composed of 95 to 99.5% by weight of conventional polyester as a main component and 0.5 to 5.0% by weight of crystallization inhibitor, single yarn fineness of 1.0 denier or less, and elongation at break of 120% or more. .

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

Polyethylene terephthalate having an intrinsic viscosity of 0.64 was dried at 155 ° C. for 4.5 hours. After melting the chip with a melt extruder, a continuous screw extruder having a glass transition temperature of 105 DEG C and 0.9% by weight of methyl methacrylate / styrene-based copolymer and 91.1% by weight of the polyethylene terephthalate melt (35 mm diameter twin screw extruder (temperature 300 ° C.). In addition, the fine kneading was continuously passed through a 20-stage stationary kneader.

In addition, the polymer melt thus mixed is spun through 36 spinneret perforated spinnerets, and then cooled and solidified by sending 22 ° C. cooling air at a rate of 0.5 m per second (X / Y = 1.0). After winding, a polyester partial alignment yarn having a single yarn fineness of 0.8 denier was prepared. 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 Crystallization Inhibitor Properties Winding speed (m / min) Cooling condition (X / Y) Resin type Glass transition temperature (℃) Added amount (% by weight) Example 1 Methyl methacrylate-styrene copolymer 105 0.9 4,200 1.0 Example 2 Methyl methacrylate-styrene copolymer 105 2.5 4,500 0.9 Example 3 Polymethyl methacrylate 106 1.5 4,800 1.2 Example 4 Polymethyl methacrylate 106 3.5 4,300 1.1 Example 5 polystyrene 107 2.9 4,300 1.0 Example 6 polystyrene 107 4.0 4,100 0.9 Comparative Example 1 - - - 4,500 0.8 Comparative Example 2 Polymethyl methacrylate 106 0.1 4,200 1.4

Workability and Yarn Property Evaluation Results division Radiation workability Partial Incliner Elongation Flammability 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 is uniformly mixed with the polyester polymer and the crystal orientation inhibitor which is a crystal orientation inhibitor excellent in drawing 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 (6)

In preparing polyester fiber by melt spinning the polyester polymer, 0.5 to 5.0% by weight of the crystal orientation suppressor is uniformly mixed with the conventional polyester polymer in the molten state, and then discharged through the detention and average cooling of the multifilament A polyester fiber characterized in that the speed gradient is cooled and solidified with a cooling wind so as to satisfy the condition of the following formula (I), and then the single fiber fineness is spun to 1.0 denier or less at a winding speed of 4,000 m / min or more continuously. Manufacturing method.                        -Below- 0.9

〈1.2 (I) Wherein X is the multifilament average cooling rate gradient of the present invention, and Y is the multifilament average cooling rate gradient under the condition that the winding speed is 3,200 m / min and no crystal orientation inhibitor is added. 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. The method for producing a polyester fiber according to claim 1, wherein the crystal orientation suppressor in the molten state and the conventional polyester are mixed with a stationary kneader. The method for producing a polyester fiber according to claim 1, wherein the conventional polyester in the molten state and the crystal orientation suppressor on the solid are melted and mixed in a twin screw extruder. A polyester fiber composed of 95 to 99.5% by weight of ordinary polyester as a main component and 0.5 to 5.0% by weight of crystallization inhibitor, having a single yarn fineness of 1.0 denier or less, and an elongation at break of 120% or more. The polyester fiber according to claim 5, wherein the crystallization inhibitor is a polymethyl methacrylate resin, a polystyrene resin, or a methyl methacrylate-styrene copolymer resin.