JPS61113817A - Production of polyester fiber - Google Patents

Abstract

PURPOSE:To decrease the frequency of breakage of spun yarn, and obtain a yarn having high orientation and crystallinity, by passing a spun polyester yarn through a heat-insulation zone and an evacuated spinning cylinder attached just below the spinneret under specific spinning condition, and taking up the spun yarn. CONSTITUTION:A heat-insulation zone 8 of >=50mm long is placed just below the spinneret 7, and the air in a spinning cylinder is evacuated with an evacuation apparatus 12 and the suction pipe 23. The yarn produced by the melt spinning from the spinneret 7 is introduced through the heat-insulation zone 8 into the evacuated spinning chamber Sa maintained in evacuated state, and transferred under cooling with the heat-exchanger 29. After cooling the polyester yarn Y to <=TA+20 deg.C (TA is temperature of outer atmosphere) in the spinning chamber Sa, the yarn is wound at a speed of >=4,000m/min.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing polyester fiber. More specifically, when manufacturing polyester fibers that can be used for practical purposes in a single spinning process, polyester fibers are used to reduce yarn breakage during spinning and to achieve stable production of highly oriented and highly crystalline yarns. The present invention relates to a new manufacturing method.

<Prior art and its problems> As a method for producing polyester fiber, for example, the
In the high-speed spinning method disclosed in Japanese Patent No. 5-4104, there are two major problems that must be solved for industrial realization. One is its inferiority in terms of physical properties, in that the degree of orientation does not increase much and its mechanical properties are inferior to conventional drawn yarns.
Another problem is the operation where thread breakage occurs frequently during spinning.
This is the problem above. These problems become more apparent as the yarn to be manufactured becomes thinner, making it impossible to produce yarn by high-speed spinning.

Among these problems, improvement of physical properties 1! The aim is to

Various methods have been proposed for improving the degree of yarn orientation by adding some operation during the spinning process. ``In order to achieve highly oriented and highly crystallized yarn obtained in the spinning process, it is thought to be effective to increase the stress applied to the yarn during the yarn deformation process1. However, this method causes great damage to the yarn and increases the number of yarn breaks. In order to deal with the increase in stress applied to the yarn, a method that can be realized in terms of operation is to increase the pressure in the atmosphere around which the yarn runs. This pressure spinning method is applied to the spinning process, and the take-up speed is 4.
．． If the atmospheric pressure is increased to increase the stress applied to the yarn under low spinning speeds of less than OOOm/min, the degree of orientation of the obtained yarn will certainly increase. ``However, if this method is directly applied to high-speed spinning at a spinning speed of 4,000 m/min or more,
The behavior is clearly different from that at low speeds, and the contribution to improving the degree of orientation is extremely small, and may even decrease. Therefore, the atmospheric pressure under high-speed spinning and the physical properties of the obtained yarn (degree of orientation,
In the process of examining the degree of crystallinity in more detail,
The present inventors have arrived at an idea that is completely opposite to the conventional idea of reducing the atmospheric pressure during high-speed spinning.

child Rin conducts an experiment to confirm the point.

An example of reducing the pressure of the atmosphere during high-speed spinning is as follows:
There is one disclosed in Japanese Unexamined Patent Publication No. 59-94614. This method aims to reduce the spinning tension and improve the spinning stability in godetless spinning, but it does not meet the aim of the present inventors, which is to eliminate yarn breakage while improving the physical properties of the yarn. Not disclosed. In particular, regarding the improvement of physical properties, this is in the opposite direction to the conventionally known technical idea, and the above-mentioned publication does not contain any description regarding this matter. In fact, if the method described in JP-A-59-94614 is applied as is, the spinning tension can certainly be reduced, but the degree of orientation of the resulting yarn remains almost unchanged.

On the contrary, it even decreased. Furthermore, although this method is effective in godetless spinning,
In actual operations, not using Godetstro 2 not only poses problems in terms of work safety, but also causes vibrations from the winding machine to propagate directly through the yarn to the spinning section, resulting in problems with the uniformity of the yarn. It often decreases.

Therefore, a spinning method that improves the physical properties in a high-speed spinning method and stably produces yarn without yarn breakage is as follows:
The current situation is that it has not yet been established.

<Object of the Invention> The object of the present invention is to produce an excellent polyester fiber that can improve yarn physical properties during high-speed spinning, obtain highly oriented and highly crystalline yarn, and reduce spun yarn breakage. The purpose is to provide a method.

<Structure of the Invention> In order to achieve this object, the present invention melts a polyester polymer and deposits 50 I2 or more directly below a spinneret.

The polyester yarn is discharged into a 9' vacuum spinning tube which is continuously provided below the upper length of the heat-retaining zone, and is cooled to form a polyester yarn.
After cooling to below 0)°C (where T is the R degree of the outside atmosphere), the spinning tube is kept sufficiently airtight and discharged from the vacuum spinning tube at a take-up speed of 4,000 m/min or more by a take-up means. It is characterized by the fact that the yarn is taken up.

The present invention will be explained in more detail below.

In the present invention, in order to reduce yarn breakage while improving the degree of orientation and crystallinity using the high-speed spinning method, a heat-retaining zone with a length of 50 mm or more is provided directly below the spinneret, and a It is necessary to provide a vacuum spinning tube and reduce the pressure of the atmosphere around which the yarn runs.

If there is no such heat-retaining zone, or if there is one, but the length is less than 50 meters, the degree of orientation and
Improvement in crystallinity cannot be achieved. The degree of orientation and crystallinity can only be improved by running a continuous vacuum spinning tube below a heat-retaining zone of 50 threads or more. Furthermore, by using such a heat-retaining zone in combination with a vacuum spinning tube, it is possible to not only improve the physical properties of the yarn but also dramatically reduce yarn breakage. According to the observations of the present inventors, 1. .

It has been found that according to the method of the present invention, contamination on the nozzle surface is significantly reduced and the flow stability of the flow discharged from one nozzle is improved. This reduction in yarn breakage is considered to be due to this effect. The above-mentioned effects of reducing yarn breakage and improving physical properties are due to the atmospheric pressure f 6Q
This becomes more noticeable when the temperature is set to 0 Torr or less and the length of the heat retention zone is set to 100 meters or more.

Furthermore, in the present invention, the take-up speed is '4. It is necessary to take off the discharged yarn with the taking-off means in 7 minutes or more at '00.0m.

As such a collecting means, a Godet roll or the like is generally used, but a hot roll or the like may also be used.

However, as mentioned above, winding the yarn directly on the winding machine, that is, making it Godetless, impairs the propagation of the vibration of the wine goo and impairs the uniformity of the yarn, which is a safety concern. This is not desirable because it causes problems. In addition, it is necessary to set the take-up speed Ifta, ooom/min or more in order to bring the degree of orientation and crystallinity of the yarn to a practically usable level. The upper limit of this take-up speed is determined from the physical properties (same effect, spinning stability, reliability of one winder, etc.)
,000 m/min is preferred.

Further, the yarn when taken out from the vacuum spinning tube needs to be cooled to below = (TA+20)°C (where TA is the temperature of the outside atmosphere). (TA +2
This is because if the temperature remains above 0°C and cooling is insufficient, thread breakage will increase.

Furthermore, the reduced pressure spinning tube in the present invention needs to be kept sufficiently airtight from the external atmosphere (atmospheric pressure).

If such airtightness is insufficient, a high degree of vacuum (degree of reduced pressure)
This is because not only the effect of the present invention cannot be obtained sufficiently, but also the pressure (degree of vacuum) in the spinning tube increases and the uniformity of the obtained yarn decreases. From this point of view as well, it is necessary that the vacuum spinning tube be provided continuously below the heat-retaining zone directly below the spinneret.

As explained above, in the present invention, an improvement in the degree of orientation of the yarn and a rapid increase in the degree of crystallinity are realized in relation to the heat retention zone and the spinning speed, and new effects are expressed. A surprising effect that is opposite to the conventional technical idea 1 can be obtained.

In this way, in the present invention, a heat-retaining zone with a length of 50 or more fabrics is provided directly below one nozzle, and a vacuum spinning tube is installed continuously below the zone, and while reducing the pressure around the yarn traveling position, After the yarn temperature has been cooled to below (TA120)'C, highly oriented and highly crystalline polyester fibers can be produced for the first time in a single spinning process by taking them off at 4,000 m for more than 7 minutes using a taking means. , it can be manufactured stably without thread breakage.

1. The present invention is particularly effective when applied to high-speed spinning of thin materials with a single yarn denier of 1 d or less.

The present invention will be specifically explained below with reference to FIG.

FIG. 1 is a schematic diagram of a reduced pressure spinning apparatus which is an example of a method for carrying out the production method of the present invention.

In the figure, the spinning machine has a raw material hopper 2, into which chips 1 are input. Melt extruder 3. Metering pump 4. It consists of a motor 5 with a transmission, a knob 62 and a base 7.

The chips 1 from the IJX material hopper 2 are passed through the metal ring bong 4 in a polymer state by the melt extruder 3 in the spinning machine, after which they are filtered by a filter (not shown) in the tsuku tsuku 6, and then threaded from the spinneret 7. The strip Y is usually melt-spun at a temperature in the range of not less than the melting point of polyester and 100° C. above the melting point. The metering bong 4 is connected to a motor 5 with a transmission, and by controlling the rotation speed of the motor 5, the amount of yarn Y to be discharged can be determined.

In the present invention, a spinneret 7 is attached and a reduced pressure spinning tube S is provided directly below the 7t hack 6, and by connecting the spinning tube to a vacuum system, it is possible to maintain the inside of the spinning tube in a reduced pressure state. be.

The vacuum spinning tube S will be described in more detail below.

A long heat-retaining zone 8 is provided between the mouthpiece surface and the bottom groove of the spin block 9. In order to improve yarn orientation, crystallinity, and reduce yarn breakage, the length L of this heat retention zone is 50 mm.
Requires IE11 or higher. This heat-retaining zone can be accessed from the bottom of the pack by sealing member 10. It is connected to the exhaust device 12 via the heat insulating cylinder 11t.

A cylindrical porous filter 13 is installed in the exhaust device 12, and is connected to the vacuum system via a vacuum system communication pipe 14 that opens to the exhaust device 12. The structure is such that the air inside the spinning tube is exhausted almost uniformly in the circumferential direction. A pulp 15 is attached to the pipe 14 to adjust the flow rate. 26
is a vacuum gauge.

The lower blade of the exhaust device 12 has a movable cylinder 17 and a fixed cylinder 18.
The movable cylindrical body 17 interlocks with a cylinder 19 attached to the movable cylindrical body.

The cylinder 19 can be moved up and down within the fixed cylinder 18 by operating the cylinder 19. During operations such as threading, the movable cylinder 17 secures a working space between the lower end of the exhaust device 12 and the upper end of the movable cylinder 17, and during normal winding.

It can rise to the position of the upper exhaust device 12 and come into contact with the pressure.

In addition, sealing members 16 and 16' such as O-rings are provided at the sliding parts between the movable cylinder 17 and the fixed cylinder 18 and at the pressure-contact parts between the movable cylinder 17 and the exhaust device 112 to prevent leakage. It is structured.

As shown in FIG. 2, the thread exit portion at the lower end of the fixed cylinder 18 has a minute slit 28 through which the thread can pass, and the pressure loss due to the resistance of the slit substantially eliminates the fluid flow. A guide holder 25 is attached with a seal guide 24 that ensures sufficient safety and stability (FIG. 2(A) shows a plan view, and FIG. 2(B) shows a side view). Seal guide 2
4, only a slight airflow flows in.

The inflow of the air current does not cause significant shaking of the yarn, but entanglement between the single yarns of the yarn 6 does not occur.

A vacuum gauge 27 and a suction pipe 25 are provided on the lower blade of the fixed cylinder 18, and the pipe 23 communicates with the outside atmospheric pressure section via the pulp 22.

Therefore, by simply bringing the movable cylinder 171c into contact with the exhaust device 12, the lower end of the fixed cylinder 18 "'-"4
A sealed space t'''' can be easily obtained in the depressurized atmosphere chamber Sa1 below the mouthpiece.

The outer wall of the IL fixed cylinder 18 is covered with a heat exchanger 29, and has a structure in which the temperature of the atmosphere in the vacuum spinning chamber Sa can be cooled by a refrigerant (not shown) K flowing inside the heat exchanger 29. .

The lower pressure reducing atmosphere chamber Sa of the mouthpiece contains pulp 22 and pulp 15.
Accordingly, the degree of vacuum B and the air flow rate in the reduced pressure atmosphere chamber Sa can also be controlled. The melt-spun yarn Y is introduced from the spinneret 7 into the reduced-pressure spinning chamber Sa maintained in a reduced pressure state while passing through a heat-retaining normal region 8 under the spinneret. The yarn Y travels through the vacuum spinning tube while being cooled.

Furthermore, the yarn Y is attached to the movable cylinder 17. Cooling is promoted and solidified while being covered by the heat exchanger 29 and traveling inside the securely fixed cylinder 18. For yarn Y, the yarn temperature I becomes 20°C or lower than the external ambient temperature at point 9.

The second Godet roll 50a, which passes through the seal guide 24 at the outlet of the pressurized atmosphere cylinder 18 and rotates at a constant circumferential speed and is installed in the outside air normal pressure section, draws the air from the reduced pressure atmosphere cylinder at a drawing speed K4.
．． It is pulled out at OOOm/min or more. In this case, the lubricant is applied to the yarn by the lubricant applying device 21 installed between the seal guide 24 and the first godet roll 30a.

The oil application device 21 is designed so that it does not affect workability.
It is preferable to install it near the outlet of the reduced pressure atmosphere cylinder.

The warping thread of the first godet roll 50a is thick.

The yarn Y is wound on the bobbin 34 of the winder 33 via the second godet roll 5 obt.

Rotation of the pobbin 34 of the winder 35 at! A tension detector 31 provided between the IE2 godet roll 30b and the winder 33 detects the winding tension of the yarn Y, and the controller 32 controls the winding tension to be approximately constant.

According to this embodiment, the amount of air flowing out from the reduced pressure atmosphere chamber Sa at the bottom of one mouth is controlled by the pulp 15 provided at the outlet of the exhaust device 12, and the pulp 22 provided at the lower end of the fixed cylinder 18 is controlled by the pulp 15 provided at the outlet of the exhaust device 12. .

By adjusting the amount of air flowing into the reduced-pressure atmosphere chamber Sa from the normal-pressure atmosphere, the amount of air flowing in the opposite direction to the running direction of the yarn Y can be made uniform while maintaining a constant degree of vacuum in the reduced-pressure atmosphere chamber Sa. It becomes possible to control.

What is the polyester polymer that can be applied to the present invention?

Polyesters containing ethylene terephthalate as a repeating unit are mainly used, but polyesters containing a small amount of additives or polyesters copolymerized with one or more other components in an amount of 15 molar or less may also be used.

Further, in the embodiments shown in the drawings, air is used as the pressurized fluid, but nitrogen, water vapor, or other inert or active gases for the polymer may be used depending on the purpose.

According to the present invention, the yarn Y has one pair of godet rolls 30a, S
It is routed by Ob and wound up after t.

Furthermore, the oil agent may be applied at any position after the yarn Y has been cooled and solidified (it may be installed in the reduced pressure atmosphere chamber Sa at the bottom of the first cap, or it may be installed in the normal atmospheric pressure section). Furthermore, the seal guide 24) may be provided with a function of applying a lubricant, and the seal guide 24 may also serve as a lubricant to the yarn.

In the heat exchanger that cools the atmospheric temperature in the reduced-pressure atmosphere chamber Sa at the bottom of the spinneret, the temperature of the air in the reduced-pressure atmosphere spinning tube rises due to heat exchange with the spun yarn.

The purpose of this is to prevent the cooling effect of the yarn from decreasing, but it is not limited to the case where the refrigerant is completely exposed to the outer wall of the fixed cylinder 18 as in this embodiment. Alternatively, means such as heat pipes may be used.

Furthermore, in this embodiment, the suction pulp 22 is opened to allow air to flow into the reduced pressure atmosphere chamber Sa below the base, and the cooling of the yarn Y is promoted by the heat exchanger 29. In some cases, these may not be necessary.

<Effects of the Invention> By employing the configurations described above, the present invention achieves the following excellent effects.

That is, in the present invention, the reduced pressure atmosphere spinning chamber from the bottom of the first spindle to the yarn exit section is set at 3,\\ at the yarn exit part 0.
By effectively sealing fluidly sufficiently with a seal guide having a minute slit that allows the yarn to pass through, it has excellent airtightness and can easily create a reduced-pressure atmosphere spinning chamber with a high degree of vacuum. I can do it. Furthermore, by guiding the yarn to this reduced-pressure spinning tube through a heat-retaining zone directly under the spinneret, it is possible to reduce the number of spun yarn breakages that increase during high-speed spinning, and to produce a yarn that can be stably used for practical purposes with high crystallinity and high orientation. The production of strips can be realized only by spinning type.

Furthermore, in the present invention, the degree of vacuum in the spinning chamber in a reduced pressure atmosphere is controlled in order to take up the yarn that has been substantially and sufficiently fluidly sealed by the seal guide with a taking means such as a body roll controlled at a constant speed I. The yarn speed can be controlled independently by these take-off means. Therefore, it becomes possible to easily control the conditions for manufacturing the yarn.

EXAMPLES Hereinafter, the effects of the present invention will be specifically explained with reference to Examples.

The methods for measuring various physical properties described in the Examples are as follows.

Strength〉 Test length 50W tensile speed E200 [7 minutes (however, take-up speed IJ [5 minutes])
,000m/min or more, test length 2001
Obtain the strength and elongation curve at a tensile rate of 1m (IQQm/min) and calculate the strength.

Orientation degree Δn〉 Measured by the compensator method using Na and D line monochromatic light.

Density> Measured using a density gradient tube of light liquid η-hebutane and heavy liquid carbon tetrachloride.

Dry heat shrinkage rate> A 10-turn skein with a circumferential length of 1 m is made using a skein removal machine, and a load of 0.1 g/d is applied to this to measure the original length LO. Next, this was heated to 160℃ and put into the open oven for 15 minutes.
Process for minutes. 0.1 g/d in sample after treatment
The treated diameter length LO is determined by applying a load, and then the dry heat shrinkage rate 1, sa is calculated using the following formula.

<Example-1> Using the spinning equipment shown in Fig. 1, the intrinsic viscosity [η] = 0
．． 65 polyethylene terephthalate at a spinning temperature of 300
Melt-spun at 20°C to the length L' of the heat-retaining zone under the nozzle.
0 m, the spinneret has a hole diameter of 0.2, the number of holes in 1φ is 24, the discharge rate is 33 g/min, and the lower part of the heat retention zone has a thickness of 40 m.
An exhaust device with a length of 200 mm and an inner diameter of 150 mm is installed through the heat insulating cylinder of the spinning tube, and this is connected to a vacuum system to exhaust air from the outer periphery of the yarn, and the atmospheric pressure inside the spinning tube can be adjusted to various degrees of vacuum. control it. The total length of the vacuum spinning tube was 3.5 m, and the winding was performed by changing the take-up speed. Under all the above conditions, the temperature of the yarn at the exit of the spinning tube is 20 to 30°C, and t(
The outside atmosphere temperature is 20℃). Table 1 shows the spinning conditions, the strength orientation degree of the resulting next thread, and the spinning conditions.

As is clear from Table 1, there is no problem with spinnability in 41 to 4 where the take-up speed is less than 4,000 m/min, but even if the atmospheric pressure is reduced, neither the strength nor the degree of orientation increases, and the density Low (
It is amorphous and has a high shrinkage rate, so it has not reached a practical thread quality. However, when the take-up speed K k is increased to 4,000n for 7 minutes, there are some problems with spinnability at normal pressure, as shown in By reducing the pressure, A6.

As shown in Figure 7, the strength is improved, the density rapidly increases, and the shrinkage rate decreases, indicating that not only a practical yarn quality is achieved, but also spinnability is improved. In addition, take-up speed 5.
At 000 m/min, as shown in Fig. 8 (the yield is low, the strength is low and the spinnability is poor, but the spinnability is significantly improved by reducing the pressure in the atmosphere, and the strength and density are further increased. It can be seen that it is improved. Collection speed 5.80
In the case of 0 m/min, there is a similar tendency as above, but especially when &1
Comparing 1 and 12, it is clear that the atmospheric pressure is 600E.
It can be seen that setting it below ilHg is more effective for improving spinnability, strength, and crystallinity.

Example-2> Changing the spinning pack length and calculating the length L of the heat-insulating zone on one spindle-
Spinning was carried out under the same conditions as 412 of Example 1 except for the changes as in 2. The physical properties of the obtained T yarn are also shown in Table 2 along with the spinning raw material. As is clear from Table 2, when the length of the heat retention zone under the spinneret reaches 50 drops, the spinnability rapidly decreases, the degree of orientation (Δn) also decreases, and the physical properties of the yarn deteriorate, such as a decrease in strength and an increase in transfer. In this way, it can be seen that the physical properties can be improved and the yarn breakage can be reduced only by reducing the pressure while keeping the heat retention zone under the cap at 5 Qrrm or more.

<Example 3> The t0 results are shown in which spinning was performed in the same manner as 7512 of Example 1, except that the length of the vacuum spinning section was changed to control the yarn density at the outlet of the spinning tube. -5.

Table 6> As shown in Table 5, the yarn temperature at the exit of the spinning tube is (outside temperature + 2
It can be seen that if the temperature exceeds 0)°C, the spinnability deteriorates significantly, which is not preferable.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a reduced-pressure atmosphere spinning apparatus as an example for implementing the manufacturing method of the present invention, and FIG. 2 shows an example of a seal guide applied to the above-mentioned apparatus.
(a) is a plan view, and (b) is a side view. 1... Chips 2... Raw material hopper 3.
・・Melt extruder 4−・Metering pump 5・
・・Motor 6 with transmission ・Puncture 7 ・Base
8... Heat retention zone under the cap 9... Spin block 10... Seal member 11... Heat insulating cylinder 12... Exhaust device 13
... Porous filter 14 ... Vacuum system communication piping 15 ... Air volume adjustment pulp 16.16' - Seal member 17 ... Movable tube 18 ... Fixed tube 19.
...Schilling-20...Cylinder lifting guide rod 21...Oil agent applying device 22...Intake air amount adjustment pulp
, j) 25...Intake piping 24...Seal guide 25...Holder 26.27...
Vacuum gauge 28... Seal guide slit 29... Heat exchanger 30a... First Godet roll 50b... Second Godet roll 31... Tension detector 32... Winder controller 53... Winding Machine 54...Bobbin

Claims (1)

[Claims] Melting a polyester polymer, discharging it into a vacuum spinning cylinder that is continuously provided below a heat-retaining zone with a length of 50 mm or more directly below a spinneret, and cooling it to form a polyester yarn;
The polyester yarn was spun in the vacuum spinning cylinder (T_A+2
After cooling to below 0) °C (where T_A is the temperature of the outside atmosphere), the yarn is discharged from the vacuum spinning tube, which is kept sufficiently airtight, at a take-up speed of 4,000 m/min or more by a take-up means. A method for producing polyester fibers, which comprises taking over the fibers.