JP2000248428A - Production of polyester filament yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a high-elongation polyester filament yarn having excellent quality by suppressing elongation unevenness, etc., while keeping a process condition even at a high speed spinning of >=4,000 m/min spinning speed. SOLUTION: This polyester filament yarn is obtained by extruding a polyester in which 0.5-3.0 wt.% of addition polymer such as polymethyl methacrylate is melt-blended from spinnerets, preferably at 280-290 deg.C, solidifying the extruded yarn by cooling and performing a melt spinning at a speed of 4,000-8,000 m/min. In the process, a moisture content in the addition polymer is made to a range of 0.20-0.35 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyester filament yarn. More specifically, the present invention relates to a method for producing a polyester filament yarn while suppressing the occurrence of breakage and the like by blending an addition polymer comprising an unsaturated monomer having a water content in a specific range when melt-spinning polyester. The present invention relates to a production method for obtaining

[0002]

2. Description of the Related Art In the melt spinning of polyester fibers, it is extremely effective to increase the amount of polymer discharged from a die as much as possible in terms of increasing productivity. It is considered to be extremely desirable from the viewpoint of reduction.

[0003] As a typical means taken so far to increase productivity, there is known a method of increasing the spinning take-off speed to increase the discharge amount from a die. However, in this method, since the take-up speed is high, the molecular orientation of the individual filaments increases, and consequently, the residual elongation of the obtained filament spun yarn decreases. As a result, as a matter of course, the draw ratio at the time of subsequent drawing or drawing false twisting decreases, so that the effect of increasing the discharge amount due to the increase in the take-up speed is offset in the drawing step.

In order to solve such a problem, it is sufficient that the spinning orientation is not increased even if the spinning speed is increased. One of the means is to reduce the temperature of the atmosphere at which the melt is discharged from the spinneret. A method of delaying the cooling and solidification of the spun yarn by raising it has been proposed. However, such a method not only requires the installation of a special heating device immediately below the spinneret, but also has a problem that it is difficult to control a cooling process, and uneven quality and thread breakage are likely to occur. As another means, a method of suppressing an increase in molecular orientation due to an increase in spinning tension due to air resistance by shortening a distance to a convergence point of a spun yarn has been proposed. There is a problem that fusion and thread breakage easily occur, and it is difficult to stably produce yarn.

[0005] As another means, there is a method of increasing the residual elongation of spun yarn by adding an addition polymer comprising an unsaturated monomer to polyester as a fiber elongation improver.
No. 32885. According to this method, a spun yarn having a high residual elongation, that is, an as-spun yarn or a drawn yarn (FOY) -like yarn obtained by an ultra-high-speed straight drawing process is obtained, including an intermediate oriented yarn (POY). According to these studies, it was presumed that high-speed spinning at a spinning speed of 4000 m / min or more was caused by dispersion unevenness of the added polymer, and it was found that there were still problems in variation in elongation and process condition.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a polyester to which an addition polymer comprising an unsaturated monomer has been added as a fiber elongation improver at a spinning speed of 4000.
It is an object of the present invention to provide a method for efficiently producing a high-quality yarn with good quality by suppressing unevenness in the elongation of the obtained yarn while maintaining the process condition during high-speed spinning at m / min or more.

[0007]

According to the study of the present inventors, the above-mentioned problem is solved when the water content of an addition polymer to be blended in a polyester is specified, the dispersibility in the polyester is improved. It was found that the process condition in the high-speed spinning at 4000 m / min or more and the suppression of unevenness in elongation of the obtained yarn can be compatible.

Thus, according to the present invention, a polyester obtained by melt-mixing an addition polymer comprising an unsaturated monomer in a range of 0.5 to 3.0% by weight based on the weight of the polyester is extruded from a spinneret, and discharged from a discharge yarn. Is cooled and solidified, and then drawn at a speed of 4000 to 8000 m / min, wherein the water content of the addition polymer comprising the unsaturated monomer is in the range of 0.20 to 0.35% by weight. And a method for producing a polyester filament yarn.

[0009]

Embodiments of the present invention will be described below in detail. The polyester used in the present invention may be any polyester having a fiber-forming ability containing an aromatic dicarboxylic acid as a main acid component.Examples thereof include polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, and Cyclohexane dimethylene terephthalate,
Examples thereof include polyethylene-2,6-naphthalenedicarboxylate. These polyesters may be copolymers obtained by copolymerizing an alcohol component such as butanediol or a dicarboxylic acid such as isophthalic acid as the third component, or may be a mixture of these various polyesters. Of these, polyethylene terephthalate polymers are most suitable.

These polyesters may contain a matting agent, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a terminal terminator, a fluorescent whitening agent, and the like, if necessary.

The intrinsic viscosity IV of these polyesters
(Measured using 35 ° C o-chlorophenol solution)
Is suitably in the range of 0.500 to 1.00, particularly preferably in the range of 0.550 to 0.700, particularly preferably 0.58 to 0.65.

Next, the addition polymer composed of the unsaturated monomer used in the present invention is substantially incompatible with the polyester, and is finely dispersed in the polyester so that the melt-discharged yarn is fine. In this case, the orientation of the polyester molecular chains is remarkably suppressed in order to cause a change in the deformation behavior at the time of formation. Preferred addition polymers include, for example, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polystyrene, polypropylene, polymethylpentene, Polyacrylate, polymethyl methacrylate,
And a derivative having a small amount of a copolymer component, and a polymethyl methacrylate polymer is particularly preferable. In addition, since the molecular weight of these polymers preferably has a function as a stress carrier independently of the polyester, the molecular weight (weight average) of at least 2,000 or more,
Particularly, the range of 8,000 to 150,000 is appropriate.

The amount of such an addition polymer to be melt-mixed into the polyester is 0.5 to 3.0% by weight, preferably 1.0 to 2.0% by weight based on the weight of the polyester.
It must be in the range of weight percent. When the mixing amount is less than 0.5% by weight, the orientation of the melt-ejected yarn is insufficiently suppressed, and the object of the present invention cannot be achieved.
On the other hand, when the content exceeds 3.0% by weight, not only does the effect of suppressing the orientation decrease, but also the concentration of stress occurs around the mixed polymer, making it difficult for uniform elongation deformation to occur. It is not preferable because it causes staining spots and the like.

In the present invention, in addition to the above requirements,
The yarn obtained while maintaining the process condition that the water content of the addition polymer composed of the unsaturated monomer melt-mixed into the polyester is within a specific range, that is, within a range of 0.20 to 0.35%. It is important to efficiently produce a high-grade high-extensibility yarn having no unevenness in elongation at a high spinning speed of 4000 m / min or more. Here, when the water content in the addition polymer is out of the above range, for example, when the water content is large, it is difficult to keep the water content constant at the time of melt-kneading, and the addition polymer in the polyester is uniform. This is presumed to be due to a decrease in dispersibility, which is not preferred because not only the unevenness of elongation of the obtained filament yarn is increased, but also the unevenness of fineness and the spinning process condition (increase in yarn breakage) are deteriorated.

The polyester and the addition polymer are extruded from a spinneret after melt-kneading. The extruder used may be either a single-screw or twin-screw extruder. A screw extruder is preferred. In order to improve the kneading property in a single screw extruder, it is preferable to change the shape of a screw groove of a Madduk type extruder or the like.

In the method of the present invention, the temperature of the polymer melt-extruded from the spinneret (hereinafter referred to as the spinneret temperature) is preferably lower than the temperature of the spinneret even when melt-spinning ordinary polyester. Increase in elongation,
It is preferable from the viewpoint of suppressing the occurrence of unevenness of fineness and breakage of yarn. this is,
This is because the elongational viscosity of the addition polymer after the discharge of the spinneret increases further upstream of the spinning line, and the function as a spinning tension carrier is exhibited. As a result, the molecular orientation of the polyester on the spinning line is suppressed. The preferred spinneret temperature is from 270 to
290 ° C., particularly in the range of 280-270 ° C.,
If it is lower than 270 ° C., although depending on the type of the polyester, the spinnability decreases, while if it exceeds 290 ° C., the heat resistance of the addition polymer generally decreases.

The cooling of the yarn extruded from the spinneret is performed in the case of side-blowing cooling, in which the wind speed is 0.15 to 0.60 m /
By maintaining in the range of seconds, it contributes to both improvement of residual elongation and suppression of elongation unevenness and fineness unevenness. Wind speed 0.1
If it is less than 5 m / sec, the unevenness of the filament yarn in the longitudinal direction is large, and it is difficult to obtain a high-quality drawn yarn or processed yarn after the fact. On the other hand, if it exceeds 0.60 m / sec, the elongational viscosity on the polyester side increases, and the increase in the residual elongation becomes small.

The cooled and solidified yarn is 4000 m / min or more, preferably 5000 m / min or more, and particularly preferably 5 m / min or more.
Withdraw at a speed of 000-8000 m / min. Pickup speed is 4
If it is less than 000 m / min, the effect of the present invention will be small.

[0019]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In addition, each evaluation item in an Example followed the following measuring method. <Moisture content> The moisture content in polymethyl methacrylate was determined according to the Karl Fischer method. <Process condition> Expressed as the number of times of yarn breakage per day when 24 spinning machines with four spindles were continuously operated for three days. <Elongation Unevenness> Twenty-four spinning machines with four spindles were operated continuously for three days, and the difference between the maximum elongation and the minimum elongation measured and sampled every hour was calculated and expressed as an average value.

Examples 1-4 and Comparative Examples 1-2 A polyethylene terephthalate chip having an intrinsic viscosity of 0.64 and a polymethyl methacrylate (P
MMA) chips are melt-kneaded with an extruder, melt-discharged from a spinneret having a discharge hole having a hole diameter of 0.2 mm and 36 holes at the temperature shown in Table 1, and then a cooling air is blown onto the discharge yarn. After cooling and solidification, an oil agent was applied and taken up at the speed shown in Table 1 to obtain a polyester filament yarn of 125 denier / 36 filaments. Table 1 shows the evaluation results of the obtained yarns.

[0021]

[Table 1]

[0022]

According to the method of the present invention, it is presumed that the dispersibility of the addition polymer comprising the unsaturated monomer in the polyester is improved, and the high-quality and high-quality film with little unevenness in elongation and fineness is observed. Elongation yarns can be produced under excellent spinning process conditions, and their industrial value is extremely large.

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[Procedure amendment]

[Submission date] December 7, 1999 (1999.12.
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

The intrinsic viscosity IV of these polyesters
(Measured using 35 ° C o-chlorophenol solution)
Is suitably in the range of 0.50 to 1.00,
A range of 0.55 to 0.70 , particularly 0.58 to 0.65 is desirable.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

[0016] In the method of the present invention, (hereinafter referred to as spinneret temperature) polymer temperatures melt-extruded from spinnerets, it is lower than the spinneret temperature for you melt spinning ordinary polyester, more Increase in residual elongation,
It is preferable from the viewpoint of suppressing the occurrence of unevenness of fineness and breakage of yarn. this is,
This is because the elongational viscosity of the addition polymer after the discharge of the spinneret increases further upstream of the spinning line, and the function as a spinning tension carrier is exhibited. As a result, the molecular orientation of the polyester on the spinning line is suppressed. The preferred spinneret temperature is from 270 to
290 ° C., are particularly suitable in the range of 280 to 290 ° C.,
If it is lower than 270 ° C., although depending on the type of the polyester, the spinnability decreases, while if it exceeds 290 ° C., the heat resistance of the addition polymer generally decreases.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

[0021]

[Table 1]

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Iwashita 77-77 Kitayoshida-cho, Matsuyama-shi, Ehime F-term in Teijin Limited Matsuyama Office (reference) 4J002 BB032 BB122 BB162 BC032 BG032 BG062 BG102 CF061 CF071 CF081 GK00 4L035 BB32 BB34 BB55 JJ15

Claims (3)

[Claims] 1. An addition polymer comprising an unsaturated monomer,
A polyester melt-mixed in a range of 0.5 to 3.0% by weight based on the weight of the polyester is extruded from a spinneret, and the discharged yarn is cooled and solidified, and then 4,000 to 8,000.
In the melt spinning method of drawing at a speed of m / min, the water content of the addition polymer comprising the unsaturated monomer is set to 0.20 to 0.1%.
A method for producing a polyester filament yarn, wherein the amount is in the range of 35% by weight. 2. The method for producing a polyester filament yarn according to claim 1, wherein the addition polymer comprising an unsaturated monomer is an addition polymer having methyl methacrylate as a main constituent unit. 3. The method according to claim 1, wherein the temperature of the polyester extruded from the spinneret is 280 to 290 ° C.