JPS6075611A - Manufacture of polyester fiber - Google Patents

Abstract

PURPOSE:To obtain the titled uniform fiber having high strength, stably, by meltspinning a polymer through a spinneret, cooling below the glass transition temperature, drawing in a hot gas stream having a specific flow rate in a hot zone keeping a specific wall temperature of the hot zone and specific temperature of the hot gas, and winding at a high speed. CONSTITUTION:A thermoplastic polyester polymer is subjected to the melt spinning through a spinneret, and cooled to a temperature below the glass transition temperature. The obtined yarn Y is transferred through a hot zone to effect the thermal drawing in the zone. In the above process, the heating cylinder 1 is furnished with plural small holes 3 and a hot-gas-supplying part 2 surrounding said holes 3, and the heating zone is heated with the electric heater 4. Hot gas satisfying the fomrula 10<=F<=80 [F is flow rate of the hot gas (Nl/min)] is introduced actively into the hot zone, and the yarn is heated under the condition to satisfy the formulas TW>70, TA>70, Tw-100<TA<TW [Tw( deg.C) is wall temperature of the hot zone, TA( deg.C) is the temperature of hot gas], and wound at a take-off speed of >=3,000m/min to obtain the objective fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing polyester fiber. More specifically, this article describes a method for stably producing polyester fibers with satisfactory mechanical properties and uniformity that can be used in practical use in a single step using only a spinning rod, without fuzz or threads. .

[Prior art and its problems]

BACKGROUND ART Various methods have been proposed for producing polyester fibers in a single step of spinning, for the purpose of reducing production costs and saving energy.

An example of such a method is the old one, Shoko Sho 45-1932.
As disclosed in the above publication, there is a method in which a melt-spun yarn is once cooled to below the glass transition temperature and then passed through a heating zone again to achieve hot drawing.

Generally speaking, a heating cylinder whose surroundings are heated is used as the heating zone, but it is not possible to simply heat the surroundings of the heating cylinder to raise the atmospheric temperature inside the heating cylinder and run the yarn.
Atmosphere inside the heating cylinder II'! As a result, the uniformity of the resulting yarn is poor, and when it is dyed into fabric, it becomes uneven and cannot be used as a product.

In addition, when such a heating cylinder is used, when the take-up speed is increased or the number of filaments in the yarn to be produced is increased, the accompanying airflow of the running yarn flows into the heating cylinder, causing the atmospheric temperature to drop. , the hot drawing cannot be carried out sufficiently, and the uniformity of the yarn deteriorates due to drawing unevenness.

In order to eliminate these drawbacks and prevent the atmospheric temperature from decreasing due to the accompanying airflow, a method has been proposed in Japanese Patent Application Laid-Open No. 138613/1984, in which the yarns are bundled and passed through a heating cylinder while removing the accompanying airflow. However, in such a method, the heat treatment efficiency is low because the yarns are bundled, and SOO
It has the drawback of requiring high temperature conditions of as high as 0.degree. C., which increases the cost.

In addition to the above, there have also been attempts to eliminate the influence of accompanying airflow by dividing the yarn into the heating zone in order to achieve uniform stretching (Japanese Patent Application Laid-Open No. 51-147615), and In order to make the deformation of the thread as slow as possible, an attempt was made to pass it through two heating zones (Japanese Patent Application Laid-Open No. 16081/1982)
have been proposed, but these can completely eliminate the influence of entrainment airflow, but do not provide a sufficiently uniform yarn.

Therefore, in the conventional technology, in the method of realizing hot drawing by passing the yarn through a heating zone in the spinning process,
The technology for stably obtaining polyester yarn with satisfactory mechanical properties and uniformity at low cost has not yet been perfected.

[Purpose of the invention]

The inventors of the invention developed mechanical properties that could be put to practical use by passing the yarn, which had been cooled during the spinning process, through the heating zone again and hot drawing it.
As a result of various studies on methods for manufacturing polyester fibers that satisfy uniformity in one step, we found that it is necessary to actively introduce heated gas into the heating zone and to control the amount of the raw ore 1 of the heated gas within a limited range. By controlling the relationship between the temperature of the heated gas just before it hits the yarn and the temperature of the wall surface of the heating zone within an appropriate range, it is possible to stably obtain a yarn that is satisfactory in both mechanical properties and uniformity. This is what led to the present invention.

[Structure of the invention]

That is, in the present invention, a thermoplastic polyester polymer is melt-spun from a spinneret, once cooled to below the glass transition temperature, the yarn is run through the heating zone again, and the yarn is heated and drawn in the heating zone. When heating, a flow of heated gas ff1F (Nj'/min) is introduced into the heating zone under conditions that satisfy the following formula I, and the wall temperature of the heating zone 1 W (℃) and the temperature TA of the heated gas are )(℃') is expressed by the following formula II, I,
This is a method for producing polyester fiber, which is characterized in that the yarn is heated before being set so as to satisfy the IV, and the yarn is drawn at a drawing speed of 3 o o am/min or more.

10≦F≦80…………………………………… IT,
＞70 ………………………………………… I]T^
〉70 …………………………………………… ■Ty
−1(10<TA<TV………………………… ■Detailed explanation of the present invention The present invention will be explained in further detail below.

The polyester polymer in the present invention is mainly a polyester having egure/terephthalate as a main repeating unit, but it may also be a polyester polymer having butylene terephthalate as a repeating unit. Also, 15
A polyester polymer containing a polyester copolymerized with one or more other components in an amount below the molar coefficient and a small amount of additives may be used.

The present invention relates to a heating zone through which the yarn passes after being cooled, and a method of introducing heated gas into the heating zone while heating the atmosphere of the heating zone from the surroundings and taking the yarn at a taking rate of 3DOOrp/min or more. .

In particular, it is important to introduce heated gas into the heating zone and under what conditions.
controlling the flow rate of the heated gas within a limited range;
The temperature of the heated gas must be set within a certain range with respect to the temperature of the heating zone wall surface.

In other words, simply passing the yarn through a heating zone where the ambient temperature is increased by heating the surrounding area will result in an increase in the take-up speed.
In particular, when the take-up speed is 300 [1 m/min], the uniformity of the yarn obtained rapidly decreases.

However, the inventors have discovered that at this time, if heating gas is introduced into the heating zone at a flow rate within a limited range, deterioration in the uniformity of the yarn can be suppressed.

At this time, the flow rate of the heated gas introduced into the heating zone t is the first point of the present invention. In other words, the flow rate of heated gas is 1
0~80 NI! /min, a yarn with satisfactory mechanical properties and good uniformity can be obtained. If the flow rate is less than 10 N, g1 min, the uniformity of the yarn will deteriorate, the mechanical properties will also deteriorate, and the effect of heating gas introduction will not be fully demonstrated, and the flow rate will be 80 NI! If it exceeds 7 minutes, the uniformity deteriorates, and at the same time, the number of fluffs and yarn breakage increases rapidly, reducing the stability of the operation. Particularly from the viewpoint of yarn uniformity, the flow rate is preferably 10 to 50 Nl/min, and more preferably 20 to ao Nl/min.

In addition to the above points, the temperature of the heating gas and the temperature of the heating zone wall are the second points of the invention.

First of all, in order to uniformly draw the yarn in the heating zone, it is essential that the temperature TA of the heated gas just before it hits the yarn and the temperature Tw of the heating zone wall surface are both higher than 70°C. be. If either TA or Tw is 70° C. or lower, stretching in the heating zone cannot be performed sufficiently, resulting in deterioration of the mechanical properties of the yarn and deterioration of uniformity due to fluctuations in the stretching point. In particular, a range of 100 to 600°C is good for both TA and Tw.

In addition to this, it has been found that the relationship between the temperature TA of the heating gas and the temperature 'rwO of the heating zone wall surface has a significant influence on the uniformity. According to experiments by the inventors, TA is
It has been found that a uniform yarn can be obtained only when the setting is made so that w satisfies the relationship Tw 100 < TA < TV ('C). According to the observations of the present inventors, when the temperature of the gas immediately before hitting the yarn is set to be higher than the temperature of the inner wall surface of the heating zone, the running state of the yarn in the heating zone suddenly becomes unstable and the uniformity deteriorates. At the same time, fluffing and yarn breakage occur frequently during spinning. On the other hand, if the temperature of the heated gas is too low relative to the temperature of the inner wall of the heating zone, the uniformity will be significantly reduced. According to experiments conducted by the present inventors, it was found that the critical range is TA>'1:'w 100 (°C).

In addition, in the present invention, the yarn that has passed through the heating zone as described above is taken off at a take-up speed of 300 m/min. If the take-up speed is less than 3000 m/min, firstly, a yarn with sufficiently satisfactory mechanical properties cannot be obtained. Furthermore, if the take-up speed is less than 3000 m/min, the heating zone t as in the present invention is
The effect of introducing the heated gas tends to deteriorate the uniformity of the reverse die.

That is, in the present invention, heating gas is introduced into the heating zone at an appropriate flow rate at a take-up speed of 3000 m/min or more, and the temperature of the heating gas is controlled within a limited range with respect to the temperature of the heating zone wall surface. For the first time, yarn with satisfactory uniformity and mechanical properties can be stably obtained without fuzz or yarn breakage.

Note that as the heating zone in the present invention, a tube having a cylindrical shape or a rectangular cross section can be used.
The shape is not limited to the above shape as long as the space in which the thread runs is heated.

Further, the method for raising the temperature of the atmosphere in the heating zone is generally to heat the periphery of the heating zone by electric heating or heating with a heating medium, but the method is not limited to this.

Furthermore, the heating zone of the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a heating cylinder showing an example of a heating zone used in the present invention. In FIG. 1, 1 is a heating tube, 2 is a heating gas supply section, 3 is a small hole, and 4 is an electric heater. The cooled yarn Y travels within the heating cylinder 1 without contacting the heating cylinder and undergoes a heat treatment. A heated gas supply section is provided so as to surround a plurality of small holes 3 formed in the heating cylinder 1, and heated gas is introduced into the heating cylinder through the small holes 3.

As for the method of introducing the heated gas, although a method of introducing the heated gas through the small hole 3 is shown in FIG. 1, the method is not limited to this.

In addition to air, inert gases such as nitrogen and helium, water vapor, and the like can be used as the heating gas, but air or inert gases are particularly preferable because there are fewer operational problems.

In addition, the yarn introduced into the heating zone should be cooled down to T9 or below, and especially preferably completely cooled to room temperature. It is preferable that the yarn is not bundled.This is because, as mentioned above, when the yarn is introduced into the heating zone in a bundled state, the temperature of the yarn increases. Therefore, the heating zone must be kept at a very high temperature. This is because it is disadvantageous in terms of cost.

〔Effect of the invention〕

As mentioned above, heating gas is introduced into the heating zone at an appropriate flow rate, and the temperature of the heated gas is controlled within a limited range with respect to the temperature of the wall surface of the heating zone, and the heating gas is withdrawn at a withdrawal speed of 3000 m/min or more. Only by doing so can a drawn yarn with excellent mechanical properties and good uniformity be produced with good operational performance.

The polyester fiber obtained by the present invention has excellent properties such that it has almost the same performance as conventional drawn yarn and can be used in all fields where conventional drawn yarn is applied.

The present invention will be explained in more detail with reference to Examples below.

In addition, the physical properties in Examples were measured as follows.

A0 strong elongation The strong elongation was measured using a Tensilon tensile tester manufactured by Toyo Baldwin Co., Ltd. under conditions of a sample length of 2QQW and a tensile speed of 100 shoes/min.

B. Uniformity (Worcester's mottling) Yarn speed 25
m/min, range ±125%, chart speed 5 crn/min, thickness unevenness in the fiber axis direction was measured, and the U% value was calculated.

Example-1 Polyethylene terephthalate melted at 290°C with 30 holes
It was discharged from the nozzle (diameter 0.2Nφ). The discharge L1 was set to 35.09 per minute. 25 to the thread discharged from the nozzle.
After cooling the yarn to room temperature by blowing cooling air at 25℃ over a length of 1m for 7 minutes, a yarn with a length of 1m and an inner diameter of 15mm was installed 2m below the nozzle as shown in Figure 1. The yarn was introduced into a heated cylinder.

The heating cylinder was electrically heated from the periphery of the cylinder, and the wall temperature was 170 to 174°C as measured using a thermocouple. Also, on the side near the mouth of the heating cylinder, there is a hole diameter of 411μR on the inner wall of the heating cylinder.
Four small holes of φ were provided, and heated air was introduced through the small holes. The temperature of the heated air just before it passed through the small holes was measured using a thermocouple and was found to be in the range of 125 to 137°C.

While changing the flow rate of the heated air as shown in Table 1, the take-up speed is 5.
000 m 7 minutes to collect 63 denier, 50 filler, l
A thread of thread was obtained.

Table 1t includes the strength and elongation of the wound yarn and υ% idi.
I showed this.

As is clear from Table 1, the flow rate ID within the range of the present invention
163 to 169 satisfying ~80 N13/min,
It can be seen that a yarn with almost satisfactory uniformity and high mechanical quality can be obtained. Especially from the point of view of uniformity, the flow rate is 10~
It can be seen that 50 Nip/min is preferable, and that uniformity is further improved at 20 to 40 Nip/min.

However, A1.2, where the flow rate is less than 10 Nl 1 minute, is not preferable because the mechanical properties are also deteriorated and the uniformity of z is also deteriorated as the U% value becomes large. Also, the flow rate is 8
A thickness of 10 to 12 times greater than 0 Nl is not preferable because not only the uniformity deteriorates but also fluff increases rapidly.

Example-2 The flow rate of the heated air introduced into the heating zone is kept constant at 2ONeZ, and the temperature TA of the heated air and the wall temperature 'r of the heating zone are
A 66 denier 30 filament yarn was obtained under the same conditions as in Example 1 except that w was changed as shown in Table 2. The strength and elongation of the obtained yarn and the U value are shown in Table 2.

As is clear from Table 2, in examples where either or both of r, q'W is 70°C or lower (marked with ○ in the table), the mechanical properties are low and the U% value is large, resulting in poor uniformity. It can be seen that only poor yarns are obtained.

Also, even if 'rA and 'rw are higher than 70℃, 'r
In the case where A<'rw is not satisfied (marked with △ in the table), not only the uniformity deteriorates but also fluff increases rapidly, which is not preferable. Furthermore, it can be seen that in cases where 'I', -TA<100 is not satisfied (marked in the table), the U% value also increases, which is not preferable.

In Table 2, yarns with satisfactory uniformity and mechanical properties can be obtained with less fluff and workability when T71>70 Tw
>70 Tw I G O < TW < TW This is only the case of A17, 21, 22, 27-29.

Example-5 The flow t^ of heated air introduced into the heating zone is 0 and 20
Assuming that the vorticity of the heated air is constant at N17 minutes, the vorticity of the heated air is TA1, the temperature of the heating zone wall surface IJ'w is TA=128~131℃T, =
63 under the same conditions as Example 1 except that the discharge amount and take-up speed were changed as shown in Table 3 at 168 to 172°C.
A yarn of denier-3o filament was obtained. The strength and elongation of the obtained yarn and the U% value are shown in Table 3.

Table 3 As is clear from Table 3, when the take-up speed is less than 3 Om/min, the strength and elongation of the yarn obtained by passing through the heating zone is low and does not reach a level that can be put to practical use. In addition, there is no significant difference in strength and elongation properties whether the heated air flow [l] is 0 or 20 Nl/min, and the uniformity tends to deteriorate with the introduction of heated air.

However, when the take-up speed is 3000 m/min or more, the effect of introducing heated air becomes significant, and the flow rate specified in the present invention,
Starting with the conditions of heated air and heated cylinder wall that meet the temperature,
It can be seen that a yarn with good mechanical properties and uniformity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a heating cylinder showing an example of a heating zone used in the present invention. 1: Heating cylinder 2: Heating gas supply section 3 = Small hole 4: Electric heater Y: Thread patent applicant Toshi Co., Ltd. 11 1 = To 2 Te----゛4 Procedure number 1n official text +59.5. 48 Kazuo Wakasugi, Commissioner of the Japan Patent Office (Monday/Monday, 1980) 1. Indication of the case 1988 Patent Application No. 181250 2. Title of invention 5. Number of inventions increased by amendment 0 6. Subject of amendment 7. Contents (1) On page 16, line 9 of the specification box, "mechanical properties are also reduced," is amended to "mechanical properties are also relatively reduced." (2) On page 18, line 3 of the specification, "mechanical properties are low" is amended to "mechanical properties are relatively low". I"2

Claims (1)

[Claims] After melt-spinning a thermoplastic polyester polymer from a spinneret and once cooling it to below the glass transition temperature, l'5
When the yarn is run through the heating zone and heated and stretched in the heating zone, the flow rate of the heated gas in the heating zone is FOJ/? /min) under conditions that satisfy the following formula I, and the wall temperature Tw (°C) of the heating zone and the temperature TA ('C) of the heated gas are determined by the following formula 11.111,! Set the yarn to satisfy V, then heat the yarn and set the take-up speed to 30110.
n+ A method for producing polyester fiber characterized by taking it off in 7 minutes or more. 10≦F≦-80・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・ITw>7
0…………………………………………・■TA＞70…
……………………………………………■Tw' 100
< TA < TV………………………………IV