KR20010100287A - A process of preparing for polyester yarn - Google Patents

Abstract

The present invention produces polyester partial alignment yarns at high speed spinning (5,000 m / min or more) by effectively delaying the phenomenon of rapid increase of the crystallization on the radiation (radiation crystallization) when producing polyester fibers at high speed spinning. It is characterized by.

To this end, the present invention adds additives having a specific molecular structure, particle size, and glass transition temperature as an orientation inhibitor during polymerization, uniformly kneads 20 or more stationary kneaders, and radiates the shear rate in the spinneret at 7,000 to 15,000 per second. .

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.

Description

Process for preparing polyester fiber {A process of preparing for 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 in the radiative force and the orientation 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 due to the increase of 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 5,000 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. '' 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 properties, in particular the spinning speed, and lowers 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 5,000m / min or more winding speed.

In addition, the present invention is excellent in the workability of spinning, stretching, and flammability, the additives can be moved to the fiber surface to prevent the yarn quality from deteriorating, while maintaining the yarn elongation at 120 or more at a winding speed of 5,000m / min or more It is intended to provide a method by which polyester partial alignment yarns can be prepared.

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, in the present invention, in the manufacture of polyester fibers by melt spinning the polyester polymer, the average particle diameter is 1 μm or less, the glass transition temperature is 100 ° C. or more, and the molecule of the additive obtained by the following formula (I): 0.5 to 5.0 weight of an additive (thermoplastic resin) having an average molecular weight (Mar) of 4 to 30 contained in the main chain or side chain is mixed with a conventional polyester polymer in a molten state, and then continuously kneaded with a stationary kneader, and spun It relates to a method for producing a polyester fiber characterized in that.

Mar () = × 100 (I)

(Wherein, Mar is the average molecular weight of the aromatic portion contained in the molecular chain or side chain per mol of the additive polymer, Mal is the average molecular weight of the aliphatic portion contained in the molecular chain or side chain per mol of the additive polymer)

Hereinafter, the present invention will be described in detail.

First, the present invention, when melt spinning the polyester polymer, the average particle diameter is 1㎛ or less, the glass transition temperature is 100 ℃ or more, the average of the aromatic part contained in the molecular chain or side chain of the additive represented by the following formula (I) 0.5-5.0 weight of additives (thermoplastic resin) whose molecular weight (Mar) is 4-30 are mixed with a conventional polyester polymer in a molten state.

Mar () = × 100 (I)

(Wherein, Mar is the average molecular weight of the aromatic portion contained in the molecular chain or side chain per mol of the additive polymer, Mal is the average molecular weight of the aliphatic portion contained in the molecular chain or side chain per mol of the additive polymer)

As the additive, a methacrylate / styrene copolymer or the like is used. The average particle diameter of the said additive shall be 1 micrometer or less. When the average diameter of the additive exceeds 1 µm, uniform mixing with a polyester melt having a high melt viscosity becomes difficult, and spinning and stretching processability of the final fiber having a diameter of 10 to 30 µm is deteriorated.

The glass transition temperature (Tg) of the said additive is made into 100 degreeC 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 additive, and to suppress the crystal orientation behavior of the polyester polymer.

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

The average molecular weight (Mar) percent of the aromatic part contained in the molecular backbone or side chain of the additive represented by the formula (I) is 4 to 30.

Due to the attractive force between the aromatic ring included in the additive and the aromatic ring included in the polyester molecule, the orientation crystallization occurring during the spinning and stretching process may be more effectively inhibited. 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.

If Mar () is less than 4, the orientation crystallization during spinning cannot be effectively suppressed and the spinning speed cannot be wound up to more than 4,000m per minute, or if Mar () exceeds 30, due to excessive action force, Due to the inherent physical properties of the ester fiber, the difference in dyeing property or occurrence of salt spots in the false twisted yarn state, which is the final fiber, is a serious problem.

In addition, the aromatic part is a rigid part inside the molecular chain, while the aliphatic part means a flexible part. Therefore, since the proper aromatic part can maintain the mechanical properties of the additive polymer chain, it plays a role of minimizing the loss of mechanical properties such as a decrease in strength by the additive fibrils distributed in the polyester.

In view of this, the additive of the present invention can maintain physical properties, particularly strength, similar to that of polyester partial alignment yarns prepared by the general method. On the other hand, when Mar () is less than 4 or exceeds 30, the strength decreases. In particular, when the condition exceeds 30, the strength drops to a serious level.

The amount of the additive added is 0.5 to 5.0 weight based on the weight of the entire polymer (polyester polymer + additive). If the added amount is less than 0.5 weight, the effect of inhibiting radiocrystallization is insignificant, and if the added amount is more than 5.0 weight, the stretching and flammability processability deteriorate.

Next, the present invention kneads the mixture of the polyester polymer and the additive continuously with a stationary kneader of 20 stages or more, and spins at a winding speed of 5,000 m / min or more at a shear rate of 7,000 to 15,000 per second in the spinneret.

The stationary kneader serves to make the additive distribution inside the melt more uniform. In the case of the present invention, more uniform kneading is required, so it must pass through 20 or more stationary kneaders. That is to say, kneading more than 1 million (2 ²⁰ ) times, uniform distribution of additives is possible, and it is possible to prevent the occurrence of salt spots in the false twisted state of the final product.

Otherwise, if the stationary kneader of less than 20 stages is adopted, deterioration of the quality due to the occurrence of fine salt spots in the twisted yarn state, as well as deterioration of workability in the stretching and the combustion process, will result in a difficult operation. . In addition, the shear rate in the spinneret should be continuously discharged at 7,000 or more and less than 15,000 per second.

The shear rate in the spinneret is a dominant factor that determines the radial distribution of the additives distributed inside the spun yarn. If the shear rate is low, the degree of orientation of the additive in the fiber axis direction may be lowered, thereby reducing the effect of inhibiting the orientation crystallization of the polyester fiber by the additive. On the other hand, if the shear rate is too high, the distribution of the additive There is a problem that is concentrated on the surface portion of the fiber may occur a problem of strength degradation.

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, which is the scope of the present invention, the effect of suppressing the orientation crystallization of the polyester fiber is sufficiently exerted, and the distribution of the additive in the fiber radial direction is appropriate. So that the strength of the partially oriented yarn and the false twist yarn can be properly maintained.

After homogeneous kneading under the above conditions, the partially aligned yarns spun under appropriate conditions are continuously wound at a speed of 5,000 m / min or more. If the spinning speed is at least 5,000 m / min, productivity is improved by 40. The spinning speed of less than 5,000m / min is a small productivity improvement, so it is not profitable in terms of economics such as the return on facility investment.

In addition, the cutting elongation of the partial oriented yarn wound at a speed of 5,000 m / min or more was 120 or more. When the cutting elongation is 120 or more, the crimp frequency is high, and the crimp quality can be obtained with good crimp quality, and excellent flammability can be secured. 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).

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

Examples 1-12 and Comparative Examples 1-5

Polyethylene terephthalate having an intrinsic viscosity of 0.64 and 0.3 wt% of titanium oxide was dried at 155 ° C for 4.5 hours. After melting the chip with a melt-extruder, the glass transition temperature was continuously added to the methacrylate styrene / styrene copolymer as shown in Table 1 as an additive, and a biaxial screw having a diameter of 35 millimeters with a diameter of 300 mm at various mixing ratios as shown in Table 1 Mix in an extruder. 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 the cooling air at 22 ° C. is sent at a rate of 0.5 m per second to cool and solidify. A partial alignment yarn was prepared. At this time, the shear rate and the winding speed in the spinneret are shown in Table 1.

The twisted yarn was manufactured using the Murada 33H (manufactured by Murada Co., Ltd.) stretch-simultaneous combustor as the partial alignment yarn of Examples 1 to 12 prepared as described above. 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.

Polyester partial alignment yarn manufacturing conditions division Additive properties Stationary kneader (single) Shear rate (per second) Winding speed (m / min) Average particle size (㎛) Tg (℃) Mar () Addition amount (weight) Example 1 0.08 105 5 0.9 20 9,000 5,000 Example 2 0.06 100 15 1.3 25 11,000 5,000 Example 3 0.08 105 5 1.5 20 12,000 5,000 Example 4 0.1 100 20 3 20 11,000 5,000 Example 5 0.08 105 5 4 25 12,000 5,000 Example 6 0.06 100 15 0.5 20 11,000 5,000 Example 7 0.1 100 20 One 25 11,000 5,000 Example 8 0.08 105 5 0.9 20 10,000 5,500 Example 9 0.08 105 5 1.5 20 13,000 5,500 Example 10 0.08 105 5 4 25 13,000 5,500 Example 11 0.1 100 20 One 25 15,000 5,000 Example 12 0.1 100 20 One 25 700 5,000 Comparative Example 1 - - - - - 12,000 5,000 Comparative Example 2 1.0 100 20 One 25 15,000 5,000 Comparative Example 3 0.1 100 20 One 10 15,000 5,000 Comparative Example 4 0.1 100 20 One 25 16,000 5,000 Comparative Example 5 0.07 98 45 One 25 12,000 5,000

Workability and Yarn Property Evaluation Results division Radiation workability Partial Oriented Shinto () 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 120 Good 43 none Example 7 Good 120 Good 41 none Example 8 Good 120 Good 39 none Example 9 Good 126 Good 36 none Example 10 Good 132 Good 37 none Example 11 Good 121 Good 45 none Example 12 Good 134 Good 43 none Comparative Example 1 Bad 83 Bad 28 has exist Comparative Example 2 Somewhat defective 110 Bad 29 has exist Comparative Example 3 Somewhat defective 115 Bad 30 has exist Comparative Example 4 Somewhat defective 115 Bad 28 has exist Comparative Example 5 Bad 126 Bad 29 has exist

When satisfying the requirements of the present invention as described above, even in the case of spinning and winding at a speed of 5000 m / min in Examples 1 to 12, the workability of the spinning process is secured stably, the elongation of the partial alignment yarn is 120 or more.

On the other hand, in Comparative Examples 1 to 5, which do not meet the requirements of the present invention, when spinning at a rate of 5,000 m / min, there is a lot of trimming, and the elongation of the partial alignment yarn does not reach 120. It resulted in not having proper physical properties.

In addition, when the requirements of the present invention are satisfied, the workability of the twist is good, the quality of the twisted yarn is excellent, and the twisted yarn of excellent quality can be obtained with little occurrence of salt spots after dyeing.

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 5,000m / min or more. As a result, productivity is improved. In addition, the present invention is uniformly mixed with the polyester polymer and the additive of the orientation inhibitor is excellent in stretching and flammability processability. In addition, the present invention can effectively prevent the phenomenon that the additives move to the yarn surface to lower the yarn quality.

Claims (5)

In melt-spun polyester polymer to produce polyester fibers, the average particle diameter is 1㎛ or less, the glass transition temperature is 100 ℃ or more, contained in the molecular chain or side chain of the additive obtained by the following formula (I) 0.5 to 5.0 weight of an additive (thermoplastic resin) having an average molecular weight (Mar) of 4 to 30 in an aromatic part is mixed with a conventional polyester polymer in a molten state, and then is continuously kneaded with a stationary kneader, and characterized in that the poly Process for producing ester fiber. Mar () = × 100 (I) (Wherein, Mar is the average molecular weight of the aromatic portion contained in the molecular chain or side chain per mol of the additive polymer, Mal is the average molecular weight of the aliphatic portion contained in the molecular chain or side chain per mol of the additive polymer) The method for producing a polyester fiber according to claim 1, wherein the winding speed is 5,000 m / min or more. The method for producing a polyester fiber according to claim 1, wherein the elongation at break is 120 or more. The method of producing a polyester fiber according to claim 1, wherein the additive and the polyester polymer are kneaded with at least 20 stages of stationary kneader. The method of claim 1, wherein the shear rate in the spinneret during spinning is 7,000 to 15,000 per second.