JP2003278030A - Method of production for polyester hollow fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of production for stably producing polyester hollow fiber with ≥25% of percentage of hollowness. <P>SOLUTION: The method producing the polyester hollow fibers with ≥25% of percentage of hollowness by melt spinning a polyester which is obtained by polycondensation using a catalyst excluding antimony compounds, comprises using a spinneret having discharge openings comprising more than one slits, discharging the melt polymer in 5-12 cm/s of discharging linear velocity, and winding up after bundling the cooled/solidified polymer threads at a position 40-100 cm lower from the spinneret face. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for stably producing a hollow polyester fiber. 2. Description of the Related Art Polyester hollow fibers generally have a structure shown in FIG.
As shown in (1), molten polyester is discharged from a discharge hole formed of a plurality of slits and spun. When the molten polyester is discharged from the discharge hole having such a complicated shape, foreign substances accumulate around the slit of the discharge hole with the elapse of the spinning time, and the formation of the hollow is inhibited, and the hollow tear as shown in FIG. 2 occurs. become. Further, the turbulence of the discharged polymer flow becomes large due to the grown foreign matter in the vicinity of the slit, and the yarn often breaks. Japanese Patent Application Laid-Open No. 59-82408 discloses a polyester melt spinning method for reducing the growth of foreign matter around the slit, stabilizing the flow of the discharged polymer, and stably forming the hollow. Discloses a method in which a polyester obtained by condensation polymerization without using an antimony compound is melt-discharged from a hollow discharge hole formed of a plurality of slits. Certainly, when polyester containing no antimony compound is melt-discharged, the growth of foreign matter accumulated around the slits is smaller than in the case of melt-discharge of polyester containing an antimony compound. However,
When a polyester multifilament having a high hollow ratio of 25% or more is produced by melt spinning, it is difficult to stabilize a polymer stream over a long period of time only by using a polyester containing no antimony compound. The problem that hollow tears occur frequently and spinning breakage occurs frequently and it becomes difficult to stably wind up the spinning yarn remains. [0005] The present invention has been made on the background of the above-mentioned prior art, and an object of the present invention is to provide a method for stably producing a polyester hollow fiber having a hollow ratio of 25% or more. To provide. The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the above-mentioned problems have been solved by a polyester polycondensed using a polymerization catalyst containing no antimony compound. Is melt-spun to produce a hollow fiber having a hollow ratio of 25% or more, using a spinneret having a discharge hole composed of a plurality of slits, and a discharge linear velocity of 5 to 12 cm / sec.
It has been found that this is achieved by discharging the molten polymer in the range of c, bundling the cooled and solidified polymer yarn at a position 40 to 100 cm below the spinneret surface, and then taking the bundle. An embodiment of the present invention will be described below in detail. The polyester in the present invention is a polyester in which ethylene terephthalate accounts for 85 mol% or more, preferably 95 mol% or more as a repeating unit. A small amount (usually 15 mol% or less based on the terephthalic acid component) of a component other than the terephthalic acid component and / or the ethylene glycol component may be copolymerized. The intrinsic viscosity of the polyester (ortho-35 ° C)
(Measured using a chlorophenol solution as a solvent) is preferably one having an intrinsic viscosity of 0.45 to 0.70, which is about the same as that of polyester usually used as a cloth material for clothing.
These polyesters may contain known additives, for example, pigments, dyes, matting agents, antifouling agents, fluorescent brighteners, flame retardants, stabilizers, ultraviolet absorbers, lubricants, and the like. In the present invention, a polycondensation is carried out using a non-antimony compound such as a titanium compound such as titanium trimellitate or titanium tetrabutoxide as a polymerization catalyst without substantially using an antimony compound usually used as a polymerization catalyst. It is important to use polyester that has been used. [0009] FIG. 1A shows an example in which the polyester condensed without substantially using an antimony catalyst is melted, and the hollow ratio of the polyester yarn is designed to be 25% or more. Discharge is performed from a discharge hole having a plurality of slits having a shape as shown. For example, in the case of the discharge hole shown in FIG. 1A, the hollow ratio of the polyester yarn is determined by the slit width of the arc-shaped slit and the circumferential arrangement diameter (PCD).
It can be arbitrarily adjusted by changing (1 in FIG. 1). In the present invention, in the case of the discharge hole shown in FIG. 1 (a), if the slit width of the arc-shaped slit is 0.10 mm or less and the circumferential arrangement diameter (PCD) is 0.60 mm or more, the hollow ratio is 25% or more. It can be. But,
When the hollow ratio is 60% or more, it is difficult to bond between the molten polymers discharged from the plurality of slits, and it is difficult to form a hollow. In addition to the arc-shaped slit, any discharge hole having a hollow forming performance may be a discharge hole in which a rectangular slit as shown in FIG. 1B is arranged. [0010] The spinning temperature is preferably in the range of 270 to 310 ° C. When the temperature is lower than 270 ° C., the hollow ratio can be increased, but a polymer discharge failure often occurs.
When the melting temperature exceeds 310 ° C., it is difficult to make the hollow ratio 25% or more. In order to prevent the inflow of cooling air from directly hitting the surface of the spinneret, the position of a shielding plate, for example, as shown in FIG. 3, which is installed below the polymer discharge surface, is 30 to 80 mm below the surface of the spinneret. Is preferable in that the hollow ratio is 25% or more. In the present invention, the linear velocity of the polymer discharged from the discharge hole composed of a plurality of slits is 5 to 12 cm / s.
ec, preferably in the range of 8 to 10 cm / sec. The discharge linear velocity can be arbitrarily set by changing the total opening area of the discharge slit according to the polymer discharge amount. Discharge linear velocity is 5cm
When the spinning time is less than / sec, foreign matter grows around the slit as the spinning time elapses, and hollow tears occur. When the time further elapses, spinning breakage occurs, and spinning-up becomes difficult. Discharge linear velocity is 12cm
When the time exceeds / sec, it is difficult to bond the molten polymers discharged from the plurality of slits, and it is difficult to form a hollow. Further, in the present invention, it is important that the light is focused at a position 40 to 100 cm, preferably 60 to 80 cm below the spinneret surface (hereinafter referred to as a focusing distance). The bunching may be performed on the yarn guide after the oil agent is applied by the oiling roller, or may be performed by the lubrication guide (5 in FIG. 3) that performs bunching while refueling. Is more preferable in controlling the value to an appropriate range. When the convergence distance is less than 40 cm, the spinning tension becomes low, and the winding of the roller occurs, and it becomes difficult to normally wind the spinning. When the convergence distance exceeds 100 cm, the influence of the accompanying airflow on the polymer flow becomes large, and the variation in the hollow ratio between single yarns due to cooling spots becomes large. Next, the bundled yarn is taken up at a speed of 1000 to 4000 m / min through a pair of godet rollers. Here, the tension measured before the first godet roller (hereinafter referred to as spinning tension) is 0.09.
０．２0.25 cN / dtex, more preferably 0.10 to
It is preferable that the spinning is performed so as to be 0.20 cN / dtex. If the spinning tension is less than 0.09 cN / dtex, the running of the yarn becomes unstable, and the winding of the yarn around the godet roller is likely to occur. Spinning tension is 0.2
If it exceeds 5 cN / dtex, the wound package may be too hard and the release property may be poor. Thus, a polyester multifilament having a hollow ratio of 25% or more can be stably manufactured. The present invention will be described more specifically with reference to the following examples. Each item in the examples was measured by the following method. (1) Intrinsic viscosity Orthochlorophenol was used as a solvent and measured at 35 ° C. (2) Variation in hollow ratio (%) and hollow ratio A cross-sectional photograph (560 times) of a polyester multifilament wound and spun is taken, and the hollow area (A) of each single yarn cross-section except for the cross-section where hollow tearing is observed. And the area (B) surrounding the cross section was measured and calculated by the following formula, and the average value of all the measured values was defined as the hollow ratio (%). Hollow rate (%) = A / B × 100 The variation rate of the measured value (standard deviation / average value × 100) was defined as the variation of the hollow rate. (3) Hollow tear occurrence rate (%) In the cross-sectional photograph obtained in the above (2), the cross section of the single yarn having the hollow tear was counted, and the ratio (%) to the entire single yarn cross section was defined as the hollow tear occurrence rate. (4) Spinning tension (cN / dtex) Rothchi between the convergence position and the first godet roller
It measured using the tension meter (R-1192 type) manufactured by ld. (5) Spinning breakage rate (%) Except for breakage due to artificial or mechanical factors, record the number of breaks that occur each time the complete winding of the specified weight package is completed. Calculated. Spinning rate (%) = number of times of thread breakage / number of spinning spindles × 100 [Examples 1 and 2, Comparative Examples 1 and 2] Intrinsic viscosity produced by titanium tetrabutoxide in a polymerization step using a polymerization catalyst Add 0.64 polyethylene terephthalate to 16
After drying at 0 ° C., it is melted by a melt spinning equipment equipped with a screw type extruder, and has a shape shown in FIG. 1 (a), and a slit width, a circumferential arrangement diameter (PCD) and a total opening area of a slit shown in Table 1, respectively. Was discharged at a spinning temperature of 290 ° C. and a discharge rate of 25 g / min. At this time, the discharge linear velocities were as shown in Table 1. The discharged polymer is cooled and solidified by blowing cooling air at 25 ° C. from a cross-flow type spinning cylinder (the upper end of the blowing port is the same horizontal plane as the bottom of the shielding plate 50 mm below the spinneret).
After applying the oil while converging the running yarn with a guide type oiling device installed 70 cm below the spinneret surface, the spinning tension was set to 0.15 cN / dtex, and 3000 m / d via a pair of godet rollers. Pick up at the speed of 10 minutes
kg of polyester multifilament package (84 dtex fineness, 2 filaments)
4). As is clear from Table 1, the discharge linear velocity is 12 cm.
In Comparative Example 2 exceeding / sec, there were many lamination defects between the molten polymers discharged from the plurality of slits, and the hollow tearing rate was extremely high from the start of spinning. The above operation was carried out for 32 spindles continuously for 7 days, and the hollow breakage rate and the spinning break rate were observed. As is clear from Table 1, the discharge linear velocity is 5 to 12c.
In Examples 1 and 2 in the range of m / sec, a polyester multifilament having a high hollow ratio could be stably produced for 7 days. On the other hand, in Comparative Example 1 in which the discharge linear velocity was less than 5 cm / sec, foreign substances grew around the slit as the spinning time elapses, the hollow tearing rate increased, and on the fourth day of the spinning, the spun yarn was broken. Occurred frequently, and it became difficult to take up the spinning yarn thereafter, and the operation was stopped. [Table 1] [Examples 3 and 4, Comparative Examples 3 and 4] Slit width 0.06 mm, circumferential arrangement diameter (PCD) 1.00 m
m, using a spinneret provided with 24 discharge holes having a slit opening area of 0.145 cm ² and a discharge linear velocity of 8 cm.
/ Sec, and the spinning operation was performed under the same method and conditions as in Example 1 except that the convergence distance was set as shown in Table 2. In Examples 3 and 4 in which the convergence distance is in the range of 40 to 100 cm, the occurrence of spinning breakage is extremely small for 7 days, and a polyester hollow filament having a high hollow ratio can be produced stably. Was. On the other hand, in Comparative Example 3 in which the convergence distance was less than 40 cm, the spinning tension was low, the roller was wrapped, and it was difficult to continuously perform the spinning operation. Focusing distance is 10
In Comparative Example 4 having a length of more than 0 cm, the variation in the hollow ratio between the single yarns was large, and a polyester hollow fiber of practical quality was not obtained. [Table 2] According to the present invention, the hollow ratio is stably 25%.
The above polyester hollow fiber can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing one embodiment of a spinneret discharge hole used in the present invention. FIG. 2 is a schematic view showing one embodiment of a cross section of a hollow fiber for explaining hollow tearing according to the present invention. FIG. 3 is a schematic view showing one embodiment of a melt-spinning winding facility used in the present invention. [Description of Signs] 1: Circumferential arrangement diameter (PCD) 2: Spinneret 3: Shielding plate 4: Cross-flow type spinning cylinder 5: Refueling guide (focusing position) 6: First godet roller 7: Second godet Roller 8: Polyester hollow fiber package

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Hiroyuki Osaka             77 Teijin Stock Association, Kitayoshida-cho, Matsuyama-shi, Ehime             Shamatsuyama Office F term (reference) 4L035 BB31 BB40 DD03 GG02

Claims (1)

Claims: 1. Discharge consisting of a plurality of slits when producing a hollow fiber having a hollow ratio of 25% or more by melt-spinning a polycondensed polyester using a polymerization catalyst containing no antimony compound. Using a spinneret with holes, discharge linear speed 5
The molten polymer is discharged within a range of from about 12 cm / sec to about 40 to 10 cm from the surface of the spinneret.
A method for producing a polyester hollow fiber, wherein the fiber is collected at a position below 0 cm and then collected.