JPH07305229A - Method for producing modified polyester fiber - Google Patents

Abstract

PURPOSE:To stably obtain modified polyester fibers free from mixing irregularity, having a high quality, and imparted with electrostaticity, water absorbability, and stain resistance by homogeneously feeding a modifying agent having a high melt-viscosity into a polyester. CONSTITUTION:In this method for producing the modifying agent-mixed polyester fibers by combining the flow of a melted polyester having ethylene terephthate units as a main repeating unit and fed from a main extruder 1 with the flow of a melted modifying agent fed from a biaxial extruder 4 having a deaerating hole 5 capable of being subjected to a vacuum of <=20Torr, immediately allowing the produced composite flow to pass a static mixing and stirring element 8, and simultaneously spinning the mixed polymer from a spinneret, the 1/5 to 5/1 mixture of a copolyester produced by copolymerizing a polyester containing ethylene terephthalate units as a main repeating unit with a 10-50mol.% of 5-sodium sulfoisophthalate with a polyethylene oxide having a mol.wt. of 100000-800000 is used a; the modifying agent, and the modifying agent is preferably added to the polyester in an amount of 1-15wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a modified polyester fiber mixed with a modifier.

[0002]

2. Description of the Related Art Conventionally, various modifiers have been added to polyester to improve fiber performance, impart special functions, and improve texture and dyeability. The method of adding the modifier is roughly classified into the following three methods. A method of adding a modifier during polyester polymerization or before chip formation. A method in which a masterbatch containing a high concentration of a modifier is prepared in advance, blended with a base polymer during spinning, and spun. During melt spinning, in the polymer melt stream after exiting the extruder,
A method in which a melted modifier stream is separately mixed and spun.

Among these methods, the most efficient method suitable for multi-product production is the method. This is also a preferable method from the viewpoint of preventing thermal deterioration of the modifier because the modifier has the least heat history. However, in the method (1), since the difference in melt viscosity between the polymer and the modifier is large and the compatibility is generally low, both are uniformly mixed and fibers having no mixed spots are stably spun. The problem is that it is difficult. Further, when the modifier is separately melted, the viscosity of the meltable modifier is limited, so that there is a problem that a high-viscosity modifier cannot be added.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a modifier having a high melt viscosity by using the twin-screw extruder for the modifier when the modifier is mixed in a polymer melt stream in a molten state. An object of the present invention is to enable uniform extrusion and supply, and at the same time, to stably obtain a modified polyester fiber having high quality antistatic property, water absorption property, and antifouling property without mixing unevenness.

[0005]

SUMMARY OF THE INVENTION The present invention provides a polymer melt stream of polyester consisting essentially of repeating units of ethylene terephthalate fed from a main extruder at 20T.
a modifier melt flow supplied from a twin-screw extruder having deaeration holes capable of reducing the pressure to or or less is combined to form a composite flow,
In a method for producing a polyester fiber in which a modifier is mixed by immediately passing through a static mixing and stirring element and spinning from a spinneret, as a modifier, a polyester having ethylene terephthalate as a main repeating unit is used as 5-sodium sulfonate. Copolymerized polyester obtained by copolymerizing isophthalic acid in an amount of 10 mol% to less than 50 mol% and a molecular weight of 100,000 to 80
1/5 to 5 / in weight ratio with 10,000 polyethylene oxide
A method for producing a modified polyester fiber, which comprises using the mixture of 1 and adding the modifier to the polyester polymer in an amount of 1% by weight or more and less than 15% by weight.

[0006] Preferably, when the composite flow is passed through the static mixing and stirring element, the number of divisions D per element and the total number of steps n
A method for producing a modified polyester fiber using a static mixing and stirring element having a total fluid division number S = D ⁿ of 16,000 or more defined by

The present invention will be described in more detail. FIG. 1 is a schematic diagram showing an example of a melt spinning apparatus for carrying out the present invention.
As shown in FIG. 1, with respect to the polyester polymer melt flow supplied from the main extruder 1, the modifier melt flow supplied from the twin-screw extruder 4 from the screw feeder 2 via the vibration feeder 3 At the confluence point 7 via the metering pump 6, they are merged into a combined flow. At this time, the modifier is
While being melt-kneaded by the two screws in the twin-screw extruder 4, it is degassed under a reduced pressure of 20 Torr or less.

Immediately after the polymer melt stream and the modifier melt stream are combined into a composite stream at the confluence 7, the composite stream is passed through the static mixing and stirring element 8 and measured by the metering pump 9, and then the spinning pack. Then, the polyester fiber mixed with the modifier is fed from the spinneret of the spinning pack.

In the present invention, the polyester used is a polyester having ethylene terephthalate as a repeating unit, preferably polyethylene terephthalate, but dicarboxylic acids such as isophthalic acid, adipic acid, sebacic acid and 5-sodium sulfoisophthalic acid. Alternatively, a glycol component such as 1,4-butanediol or 1,4-cyclohexanedimethanol may be copolymerized, and if the polyester is substantially linear, termination of polymerization of trimellitic acid, pentaerythritol, etc. Agents may be included.

The polyester may be synthesized by any known method. When the polyester is polyethylene terephthalate, for example, terephthalic acid and ethylene glycol are directly esterified to synthesize a glycol ester of terephthalic acid or a low polymer thereof. And then polycondensation. To get polyester,
Known catalysts, antioxidants, anti-coloring agents and the like are used as appropriate.

In the present invention, the use of a twin-screw extruder capable of degassing under reduced pressure as a side-feed process makes it possible to mix a high-viscosity modifier, which has been difficult to use conventionally, with polyester. Thus, it becomes possible to stably melt-spin a spotless fiber in which the and the modifier are uniformly mixed.

In the present invention, as a modifier, 10 mol% of 5-sodium sulfoisophthalic acid is added to polyester containing ethylene terephthalate as a main repeating unit.
A mixture of a copolymerized polyester having a molecular weight of not less than 50 mol% and preferably not less than 20 mol% and not more than 40 mol% and a polyethylene oxide having a molecular weight of 100,000 to 800,000, preferably 150,000 to 600,000 is used.

The copolymerized polyester for 5-sodium sulfoisophthalic acid copolymerization may be obtained by any known method for obtaining a copolymerized polyester. If it is less than 10 mol%, sufficient water absorbency and antifouling property cannot be obtained, and if it is more than 50 mol%, the stability during spinning remarkably becomes poor. Further, when the molecular weight of polyethylene oxide is less than 100,000, a difference between spindles is likely to occur when spinning is made into multiple spindles, and when it exceeds 800,000, not only the stability during spinning becomes significantly poor, but also mixed spots occur. Occurs.

The mixing ratio of the copolymerized polyester and polyethylene oxide in the modifier is 1/5 to 5 by weight.
/ 1, preferably 1/3 to 3/1. If the mixing ratio is less than 1/5, antifouling property cannot be obtained, and if it exceeds 5/1, antistatic property cannot be obtained.

In the present invention, such a modifier is added to the polyester polymer in an amount of 1% by weight or more and less than 15% by weight. If the amount of the modifier added is less than 1% by weight, antistatic property, water absorbency and antifouling property cannot be obtained, and if it is more than 15% by weight, not only the stability during spinning remarkably deteriorates, but also mixing Spots occur.

In the present invention, the polyester polymer melt stream and the modifier melt stream are combined to form a single composite stream, and this composite stream is immediately passed through the static mixing and stirring element. The static mixing and stirring element used is a mixing device having no driving part, and the elements that are placed in the flow channel and convert the flow channel repeatedly divide, invert, and change the flow of the fluid, and Are to be mixed. By repeatedly dividing, reversing and converting the flow, the number of divisions of the flow increases exponentially to increase the mixing degree.

Assuming that the number of divisions per stage of the static mixing and stirring element is D and the total number of stages is n, the total number of fluid divisions S is S = D ⁿ
In the present invention, in order to highly disperse the high-viscosity modifier in the polymer stream, the total fluid division number S
= D ⁿ needs to pass through a static mixing and stirring element having a value of 16,000 or more, and the total number of fluid divisions is preferably 6
It is 5,000 or more, particularly preferably 260,000 or more. When the total number of divided fluids is less than 16,000, the modifier is coarsely dispersed, the stability during spinning becomes poor, and uneven dyeing is imparted to the obtained fiber due to uneven mixing.

A publicly known spinneret is applied to the melt spinning in the present invention, and the fiber is spun from the spinneret by a known method, drawn and heat-treated to give a fiber. If necessary, the obtained fiber is shaped into a processed yarn or the like, or is further subjected to any processing such as alkali weight reduction processing and dyeing finishing processing.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples. Each property in the examples was measured and evaluated by the following methods. In addition, ◎, ○, △, × of the evaluation in Table 1
Represents extremely good, good, slightly good, and bad, respectively.

Intrinsic viscosity: A sample was dissolved in a phenol / tetrachloroethane (50/50 weight ratio) mixed solvent and measured at 25 ° C. with an Ubbelohde viscometer. Fineness unevenness: The cross section of the drawn yarn was observed with an optical microscope at a magnification of 300 times and visually determined.

Antistatic performance: The following conditions Warp Polyethylene terephthalate yarn (50 denier /
18 filaments) Weft Yarn according to the present invention (100 denier / 48 filaments) Warp density 59.1 yarns / cm Weave yarn density 22.3 yarns / cm After weaving, measurement of triboelectrification discharge curve according to JIS L1094 (1988) reference method According to the law.

A friction electrification voltage measuring device EST-3 manufactured by Kanebo Engineering Co., Ltd. was used as a device, and the measurement was carried out at a temperature of 20 ± 1 ° C. and a relative humidity of 30 ± 2%. Washing of the sample, washing of the rubbing cloth (wool) with hot water, and adjustment of the sample and the rubbing cloth were in accordance with JIS L1094. 3 from the triboelectrification discharge curve obtained by measuring 5 times per sample
The electrification voltage V ₃₀ after 0 seconds and the attenuation rate D ₆₀ after 60 seconds were obtained as average values. The unit of the charged voltage is volt (V), and the sign is minus (-).

Water absorption performance: The following conditions Warp Polyethylene terephthalate yarn (50 denier /
18 filaments) Weft Yarn according to the present invention (100 denier / 48 filaments) Warp density 59.1 yarns / cm Weave yarn density 24.4 yarns / cm After weaving, alkali reduction treatment is performed to reduce weight 20 wt.
%, And the evaluation was made by the following water droplet extinction time.

(Water droplet extinction time) 20 cm from the above fabric
A 20 cm x 20 cm test piece was attached to a metal ring having a diameter of 15 cm, the distance between the test piece and the burette was set to 1 cm, and distilled water at 20 ± 2 ° C from the burette was 0.04 c.
After c was dropped, the time required for the test piece to absorb the water droplet and disappear the mirror reflection was measured, and the average value of the measured values of 10 times was shown.

Antifouling performance: 7 cm × knitted from the sample yarn
A 7 cm knitted fabric was evaluated by the following two methods. After 0.4 cc of sesame oil was attached to the test piece and dried at room temperature for 24 hours, it was washed in a bath of 25 g of a commercial detergent / 40 liters of water for 10 minutes and rinsed for 7 minutes, and stain removal was visually determined. The test piece was stirred in mud water for 30 seconds, taken out, dried as it was, and the degree of difficulty in attaching dirt was visually determined.

Example 1 Using the melt spinning apparatus shown in FIG. 1, polyethylene terephthalate containing 0.5 wt.
Melt extrusion at 0 ° C., on the other hand, from the twin-screw extruder 4, mixing ratio of copolymerized polyester obtained by copolymerizing 5-sodium sulfoisophthalic acid with 30 mol% polyethylene terephthalate and powdered polyethylene oxide having a molecular weight of 150,000 to 400,000. (Weight) 1/1 modifier at 215 ° C
Was melt-extruded, and the modifier melt flow was combined with the polyethylene terephthalate melt flow by the metering pump 6 so that the amount of the modifier added to the polyethylene terephthalate was 4 wt% to form a composite flow. The composite stream immediately passed through a static mixing and stirring element 8 having 22 stages of two-divided elements per stage, and then this composite stream was supplied to a spinning pack 10 via a metering pump 9.

Then, the mixture was spun at 271 ° C. through a spinneret having 48 circular holes each having a hole diameter of 0.8 mm, the spun yarn was cooled with cooling air, and then an oil agent was applied thereto to give 1,400.
It was wound at a winding speed of m / min. Then stretched by a conventional method,
It heat-processed and the modified polyester fiber of 100 denier / 48 filament was obtained. Table 1 shows the evaluation results of the stability during melt spinning when obtaining fibers and the fiber characteristics of the obtained fibers.

(Comparative Examples 1 and 2) In the same manner as in Example 1, except that the copolyesters in the modifier were replaced with 5-sodium sulfoisophthalic acid 8 mol% and 60 mol% copolymerized polyesters, respectively. In the same manner as in Example 1, modified polyester fibers each having 100 denier / 48 filaments were obtained. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

(Example 2) A modified 100 denier / 48 filament was prepared in the same manner as in Example 1 except that the polyethylene oxide in the modifier was replaced with polyethylene oxide having a molecular weight of 500,000 to 700,000. Quality polyester fiber was obtained. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

(Comparative Examples 3 to 4) In Example 1, polyethylene oxide in the modifier was added to a molecular weight of 20,000 and 100.
Modified polyester fibers of 100 denier / 48 filaments were obtained in the same manner as in Example 1 except that polyethylene oxide of 10,000 to 1.7 million was used instead.
Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

(Examples 3 to 4) Examples 1 to 3 were the same as Example 1 except that the mixing ratios of the copolymerized polyester and polyethylene oxide in the mixture of modifiers were changed to 1/3 and 3/1, respectively. 100 denier /
48 filaments of modified polyester fiber were obtained. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

(Comparative Examples 5-6) As in Example 1, except that the mixing ratio of the copolymerized polyester and polyethylene oxide in the mixture of modifiers was changed to 1/8 and 8/1, respectively. 100 denier /
48 filaments of modified polyester fiber were obtained. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

(Examples 5 to 6) In Example 1, the amount of the modifier added to polyethylene terephthalate was 2 w.
Modified polyester fibers having 100 denier / 48 filaments were obtained in the same manner as in Example 1 except that t%, spinning temperature was 273 ° C., the addition amount was 10 wt%, and the spinning temperature was 268 ° C., respectively. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

Comparative Examples 7 to 8 In Example 1, the amount of the modifier added to polyethylene terephthalate was adjusted to 0.
5 wt%, spinning temperature 280 ° C. and addition amount 20 wt
%, Modified polyester fibers of 100 denier / 48 filaments were obtained in the same manner as in Example 1 except that the spinning temperature was changed to 265 ° C. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber. In Comparative Example 8, it was difficult to stably obtain the fiber.

Example 7 A modified polyester fiber having 100 denier / 48 filaments was obtained in the same manner as in Example 1 except that the number of stages of the static mixing and stirring element was changed to 16. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

Comparative Example 9 A modified polyester fiber of 100 denier / 48 filaments was obtained in the same manner as in Example 1 except that the number of stages of the static mixing and stirring element was changed to 12. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

(Comparative Examples 10 to 11) In Example 1,
Except that the modifier was replaced with a modifier of copolyester only and a modifier of polyethylene oxide respectively,
In the same manner as in Example 1, modified polyester fibers each having 100 denier / 48 filaments were obtained. Table 1 shows the evaluation results of the stability during spinning and the fiber characteristics of the obtained fiber.

[0038]

[Table 1]

[0039]

EFFECTS OF THE INVENTION According to the present invention, it is possible to supply a modifier having a high melt viscosity in a uniform melted state, and a high quality of permanent antistatic performance, water absorption performance with reduced mixing spots, A modified polyester fiber having excellent antifouling performance can be stably obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a melt spinning apparatus for carrying out the present invention.

[Explanation of symbols] 1 main extruder 2 screw feeder 3 vibrating feeder 4 twin screw extruder 5 degassing hole 6 metering pump 7 confluence point 8 static mixing and stirring element 9 metering pump 10 spinning pack

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location D01F 6/86 301 K // (C08L 67/02 71:02)

Claims (2)

[Claims] 1. A modifier supplied from a twin-screw extruder having deaeration holes capable of depressurizing to 20 Torr or less in a polymer melt stream of a polyester substantially composed of repeating units of ethylene terephthalate supplied from a main extruder. In the method for producing a polyester fiber in which a modifier is mixed by combining the melt streams to form a composite stream, immediately passing through a static mixing and stirring element, and spinning from a spinneret, ethylene terephthalate is used as a modifier. In the weight ratio of the copolymerized polyester obtained by copolymerizing 5-sodium sulfoisophthalic acid with 10% by mole or more and less than 50% by mole of the polyester having 10 to 80% by weight as a main repeating unit and polyethylene oxide having a molecular weight of 100,000 to 800,000, Using the mixture of 1 and adding the modifier to the polyester polymer in an amount of 1% by weight or more and less than 15% by weight. A method for producing a modified polyester fiber, comprising: 2. A total fluid division number S defined by a division number D per one stage and a total stage number n as a static mixing and stirring element.
= Production method of the modified polyester fiber according to claim 1, wherein the use of static mixing stirring device D ⁿ is 16,000 or more.