JPH06146111A - Production of polyester yarn - Google Patents

Abstract

(57) [Summary] [Purpose] By heating and reheating the spun yarn, it is possible to stably obtain polyester fibers which are free from stains and have excellent quality and which can be directly used in woven and knitted fabrics. [Structure] The polyester fiber yarn y discharged from the melt spinning spinneret 2 and cooled is in an unfocused state at an ambient temperature of 120 ° C to
After heating in a heating device 6 having a heating zone 4 of 250 ° C. formed therein and heating, and further reheating the atmosphere temperature of a reheating device 7 provided at the outlet of the heating zone 4 to T1 + 50 ° C. to 100 ° C., 3500 m Take up and wind at a high speed of more than 1 minute.

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 polyester fiber, and more specifically, a polyester is melt-spun from a melt-spinning die and cooled, and the yarn is run in a non-focusing state in a heating zone. The present invention relates to a method for producing a polyester fiber, characterized in that the outlet is reheated and the yarn is drawn at high speed and wound up.

[0002]

2. Description of the Related Art As a method for producing a polyester fiber having mechanical properties that can be put to practical use only in a spinning step, an ultrahigh-speed spinning method is known in which a spinning take-up speed is 7,000 m / min or more (for example, a spinning speed). Japanese Patent Publication 60-47
928).

However, in such a high-speed spinning method, the workability such as threading property and the operability at the time of spinning breakage are unstable.
Further, although such an ultra-high-speed spinning method has mechanical properties that can be put to practical use, it is stretched as a woven fabric in the actual market, lacks rigidity, is spun at a low speed, and is once wound. Sufficient properties have not yet been drawn out compared to the separate drawing method in which the drawing is carried out in the subsequent separate step, and the direct drawing method in which the spinning is taken out and subsequently drawn.

Further, the ultra-high-speed spinning method has a drawback that the equipment cost of a high-speed winder or the like becomes high. Therefore, as a spinning method capable of obtaining a polyester fiber that can be put to practical use at a take-up speed of 6000 m / min or less, there is a heat-spinning method other than the separate-drawing method and the direct-drawing method. A spinning method in which a heating zone is provided between the roller and the polyester yarn melted and discharged from the spinneret is once cooled, and then the polyester yarn is heated while running in the heating zone, and then drawn is studied.

In such a hot-spinning method, the yarn heated in the heating zone is subjected to the drawing action by the spinning tension, so that it is possible to obtain a polyester fiber having mechanical properties that can be put to practical use even at a relatively low take-up speed. it can.

However, if the spinning tension in the heating zone is too low, the resulting polyester fibers have insufficient mechanical properties, so that further practical operations such as stretching are required to put them into practical use. If it is too high, monofilament breaks and /
Alternatively, spinning breaks and the like occur frequently.

As described above, it is extremely important to control the spinning tension in the heating zone, and as a method for controlling such spinning tension, there is Japanese Patent Publication No. 59-51603. Since a guide is provided just before the line entrance, tension unevenness due to stick-slip is generated,
In terms of quality, unevenness in fineness and uneven dyeing in an unstretched state are likely to occur, and monofilament breakage occurs, which is unstable in the process.

This method is further improved to control the spinning tension,
1m from the exit of the heating zone as a method that can produce stable polyester fiber with stable quality
There is a method of focusing the light at the downstream position as described above (Japanese Patent Laid-Open No. 62-62160).
No. 162015), in this method, after the polyester fibers melted and discharged from the spinneret are once cooled,
The yarn passes through a heating zone of ˜2 m, is converged at a distance of 1 m or more downstream of the heating zone, and the take-up roller is further 0.5 m or more downstream.
Although the spinning tension is sufficient, the yarn hooking work is high, and there is a problem in operability, and moreover, it is likely to be expensive in terms of equipment.

Further, as the single fibers become finer, especially in the case of single fibers having a denier of 1 denier or less, not only the dyeing unevenness becomes worse in the long spinning running length, but also the number of spinning yarn breakage increases as a process condition. Therefore, in this method, spinning is carried out by changing the position of the heating zone and the like, and considering the actual production, the equipment is fixed, and a short spinning run length is desirable so that workability is good. Also,
1 as a monofilament that can be obtained as production with the equipment fixed
Products below denier are also desired.

[0010]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and allows polyester fibers to be produced by a heat spinning method, and has a short spinning run length in terms of equipment and production work. It is intended to provide a manufacturing method capable of efficiently performing a product and capable of providing a product having a thin single fiber denier.

[0011]

[Means for Solving the Problems] That is, according to the present invention, a filament in a non-focus state in which polyester is melt-spun and then once cooled and solidified is heated by a cylindrical heating device in which an ambient temperature T1 is maintained at 120 to 250 ° C. When heating while traveling in the zone, the heating device outlet is narrowed down, and a reheating device that holds the ambient temperature T2 of the heating device outlet at T1 + 50 to 100 ° C. is provided to take up at a spinning speed of 3500 m / min or more. The method for producing a polyester fiber is characterized in that the polyester fiber is wound without being stretched.

In the present invention, the polyester fiber is intended mainly for polyethylene terephthalate, but a copolyester in which 85 mol% or more, preferably 95% or more of the repeating unit is ethylene terephthalate, or other polymers such as polyester, such as poly It may be a blended mixture of a small amount of examethylene terephthalate, nylon 6, nylon 66, polyethylene-2,6 naphthalate, polycarbonate, polymethacrylate methyl and the like.

Known additives for these polyesters,
For example, pigments, dyes, matting agents, antifouling agents, fluorescent whitening agents, flame retardants, stabilizers, UV absorbers, etc. may be included. Intrinsic viscosity IV (35 ° C.) of the polyester fiber used in the present invention
Of O-chlorophenol solution) is 0.3
The range of 1.0 to 1.0, especially 0.5 to 0.8 is suitable.

The above-mentioned polyester has a melting point (Tm)
It is spun from the spinneret at a temperature of (Tm + 50 ° C.) and the spun yarn is subsequently cooled to a temperature below the glass transition temperature (Tg). The Tg of polyester at this time is approximately 70 to 8
The temperature is about 0 ° C., and above this temperature, the molecular motion of the polyester is severe, which is not preferable in terms of shrinkage ratio and fiber forming property. For this reason, it is desired to cool to Tg or lower after melt discharge.

In order to cool the spun yarn melt-spun from the spinneret, which has the spinning holes arranged circumferentially around one or two or three rounds or is arranged in a lattice, to the above temperature, spinning is performed. Cooling about 0.5-1.2m from the die surface (usually 0.8-
In the 1.0 m) zone, it is preferable to blow a cooling gas of approximately 25 ° C. laterally or circumferentially around the spun yarn in a non-focused state to forcibly cool the spun yarn. It is possible to obtain a fine thread.

If the spun yarn is not sufficiently cooled, it is difficult to uniformly heat it in the heating zone, and the homogeneity of the obtained polyester fiber is poor. Therefore, the yarn immediately before the yarn entrance in the heating zone has a glass transition. Must be cooled below temperature.

The arrangement of the spinning holes of the spinneret is ideally one row in the circumferential direction as described above, but the outer diameter of a normal spinneret is about 50 to 100 mm, and one row in the case of multiple yarns. Since it is difficult to form multiple yarns in the arrangement, the yarns may be arranged in an equal array in two or three rows in a circumferential shape, or may be arranged in a lattice shape so that the cooling air can blow through the yarns uniformly. In the present invention, it is suitable that the number of single fibers is 24 to 72, and if it is more than that, it is 9
It will be 6 points. Also, the total denier is 30-
Although it is about 100 denier, it is preferably 50 to 75 denier.

In the present invention, the thus cooled and solidified polyester yarn is immediately in an unfocused state and the ambient temperature T1 is 120 to 250 ° C., preferably 150 to 200 ° C.
The heating device is heated while running in the heating zone of the cylindrical heating device held at 1, the outlet of the heating device is further narrowed down, and a reheating device in which the ambient temperature T2 of the outlet is kept at T1 + 50 ° C to 100 ° C is provided to provide the spinning take-up speed. It is necessary to take up at a speed of 3500 m / min or more and take up without stretching with a take-up roller or the like.

Here, the ambient temperature T1 of the heating zone is 12
When the temperature is lower than 0 ° C, the stretching action in the heating zone is insufficient, so that the mechanical properties of the obtained polyester fiber are insufficient, and when the temperature is higher than 250 ° C, a large number of spun yarns and / or single fibers are produced. It is not preferable because fusion occurs between them. When the temperature exceeds 250 ° C., when the yarn is cut by spinning, the single fibers adhere to the inside of the heating device in a broken state, so that when the yarn is re-hooked, the attached yarn does not easily cover the yarn.

The heating zone is usually formed by a cylinder having a cylindrical shape, and the inside of the cylinder may be a direct heat transfer type heater or a cast-in type heater. Means a heating device which blows and heats by using the gas or vapor to maintain a predetermined temperature.

However, in the above-mentioned heating device, a certain portion (spot) can enhance the stretching action at a very high temperature, but it is difficult to heat the entire heating zone, and the temperature lowers significantly below the heating zone, and the physical properties are improved. Was not preferable. In addition, if the number of weights increases in the same position, the difference between the weights becomes large, and the dyeing difference becomes large due to temperature unevenness.

Therefore, if the heating device of the heating medium type is used as well as the heating device described above, the heating cylinder is heated uniformly even if the number of weights increases due to the heating medium, which is preferable for quality maintenance. It is possible to suppress the temperature decrease to some extent even below the band.

However, when the heating device is attached at a position close to the cooling device, the spinning tension is lowered as described above, so that the physical properties are improved, especially the stress at the elongation of 10% at the time of load stretching (hereinafter referred to as 10% stress). ) Is lower than that of the conventional direct-rolling method, there is a problem in quality.

Therefore, in the present invention, a reheating device is provided at the outlet of the heating device to improve the physical properties and produce single fiber denier. The reheating device provided at the outlet of this heating device is formed by a small heat transfer type heater, and it is important to narrow the outlet so as to minimize the discharge amount of the wake carried by the yarn when the yarn passes. Therefore, this narrowing down suppresses a decrease in the ambient temperature T1 in the heating zone of the heating device, and enables appropriate temperature control.

Further, when the outlet of the heating device is narrowed down, the associated flow collides with the outlet portion of the cylindrical heating device to generate a turbulent flow, so that the air resistance due to the blowing up of the associated flow and the running of the yarn at the outlet portion of the heating device. And the stretching action is further strengthened, the molecular orientation of the fiber is improved, and the physical properties are improved.

Further, the ambient temperature T at the outlet of the heating device
Even if 1 is 150 ° C. or higher, the temperature drops due to the accompanying flow of the yarn, so it is necessary to attach a reheating device to the outlet of the heating device and make the ambient temperature T2 higher than T1. When T2 is the same as T1, the molecular orientation is not so strong, and the physical strength is not so high. T2 is T1
50 to 100 ° C. higher than that leads to improvement in physical properties.
If the temperature exceeds 100 ° C, the single fibers will be broken, which is not preferable.

When there is no reheating device, the position of the heating device is set to 1 from the cooling device as in JP-A-62-162015.
Since it is necessary to install it below m, the spinning tension of 1 denier or less will increase the spinning tension extremely, making the production difficult.

Next, in the present invention, the yarn which has exited the heating zone has a spinning take-up speed of 3500 m from the yarn outlet of the heating zone.
It is necessary to collect it at least per minute. Spin take-up speed is 350
When it was less than 0 m / min, the spinning tension in the heating zone was insufficient, and thus the obtained polyester fiber was a yarn having low strength and high elongation.

The preferred spinning take-off speed in the present invention is 4500.
It is a region of up to 5000 m / min. Within this range, values close to the physical properties obtained by the separate-drawing method and the direct-rolling method were obtained. 5
If it is 000 m / min or more, filament breakage is likely to occur. Furthermore, in fine denier spinning near 1 denier, the spinning tension is likely to occur in the low speed region, so 3750
-4500 m / min region is preferred. Although the spinning tension must be increased to some extent as a position for focusing the unfocused yarn passing through the yarn outlet of the heating zone, the yarn outlet of the cylindrical heating device is approximately 0.1 to 1.0 m. Is.

If it is less than 0.1, there is no space for bundling and applying an oil agent, and if it exceeds 1 m, the spinning tension becomes too high, leading to a factor of filament breakage, and the take-up roller after bundling the yarn. Position and winder position is a problem,
The equipment working position is high, which is not preferable. In the method of the present invention, there was no particular problem in terms of physical properties and workability within a range of 0.1 to 1.0 m from the yarn outlet of the heating device.

The cylindrical heating device according to the present invention has a length of 1.5 m or less below the melt spinneret, preferably 0.8 to
It is desirable to be within 1.0 m. When it exceeds 1.5 m, the spinning tension of the yarn heated and run by the heating device becomes high, and as described above, the number of filament breakage tends to increase, which is not preferable. Further, in terms of equipment, since the long spinning run length is poor, workability in production is not good, and work at high places and yarn drop are deteriorated.

Further, the diameter of the heating device is 2/5 to 1/1 with respect to the outer diameter of the melt spinning spinneret, and preferably 1/2 to 3/5. When the diameter of the cylinder is less than 2/5, not only is it difficult to remove the yarn, but also the yarn running in the heating zone comes into contact with the cylinder of the heating device, which causes uneven spots in terms of quality. The fiber becomes easy to break. On the other hand, 1 /
If the diameter exceeds 1, and the diameter of the cylinder becomes larger, heating will be insufficient, so the physical strength and 10% stress of the load elongation curve are extremely low, and it is necessary to raise the temperature of the heating device significantly. It didn't connect.

Generally, the desired physical properties are strength 4.3-
4.8 g / d, elongation 30-38%, 10% stress 2.8-
If it is 3.3 g / d or more, it is possible to satisfy the woven fabric quality in the market.

If the length of the heating device is too short, the stretching action on the yarn by heating running cannot be enhanced, and if it is too long, the heating in the heating zone becomes long and the yarn comes into contact with the inside of the heating device cylinder. The yarn swaying increases and not only the U% deteriorates, but also the stain unevenness deteriorates. Further, since it is difficult to remove the yarn, workability is significantly deteriorated. From this point, the length of the heating device is preferably within the range of 0.5 to 1.0 m. In particular, if it is less than 0.5 m, the physical properties of the yarn are not sufficiently obtained, and if it exceeds 1.5 m, the U% tends to be deteriorated, and the yarn comes into contact with the device to increase the number of filament breakage.

Further, the diameter of the reheating device needs to be sufficiently squeezed so as not to lower the ambient temperature in the heated cylinder along with the accompanying flow brought in by the yarn, but the yarn does not come into contact with this squeezing. Is required. However, if the yarn that runs through the heating zone and contacts if it is drawn too much, stick-slip will occur partially and stains in the undrawn state will be obtained. The thread passage diameter is 1/4 of the outer diameter of the spinneret
It is good to set it to about 1/15. If it is less than 1/15, the passing yarns are likely to come into contact with each other, leading to undrawn yarn or single fiber breakage.
If it exceeds / 4, the accompanying flow that is brought in and discharged at the same time as the yarn passes decreases not only the ambient temperature of the heating device but also the ambient temperature generated by the reheating device, which is not preferable from the viewpoint of improving the physical properties. .

The present invention will be described below with reference to the drawings. FIG. 1 is an example showing a process chart of the present invention. An unfocused polyester yarn y discharged from a spinneret 2 of a melt spinning pack 1 is cooled by a cooling device 3 to a glass transition temperature Tg or lower and a cooling distance L1 (1. 5 m, preferably 0.8 to 1.0 m), and then, the atmosphere temperature T1 is 120 with the jacket 5 in which a heat medium (diphenyl) is enclosed or circulated.
To 250 ° C. (preferably 150 to 200 ° C.), the outer diameter d1 of the heating device 6 having a length L2 (0.5 to 1.5 m) uniformly heated to 2/5 to the diameter of the spinneret 2 It passed through a cylindrical heating zone 4 of 1/1.

Next, a reheating device 7 is provided at the yarn outlet 8 of the heating device 6, and the diameter of the spinneret 2 is ⅙ to 1/12.
When passing through the yarn outlet 8 having the diameter d3, the ambient temperature T2 of the reheating device 7 is set to T1 + 50 to 100 ° C., the yarn y is heated again, and the oil agent is applied by the oil agent applying device 9 and at the same time the yarn y is applied. From the yarn outlet 8 within a distance L3 (0.1 to 1 m), and then the yarn entanglement device 10 is used to make the yarn y.
To the take-up winder 13 via the take-up rollers 11 and 12.

At this time, the yarn drop and the yarn hooking workability are problems in consideration of the actual production. Therefore, if the yarn outlet of the heating device 6 (the yarn outlet of the reheating device) is narrowed from the beginning, the yarn drop is performed. This makes it difficult for the reheating device 7 to be opened and closed, and when the yarn is dropped, as shown in FIG.
It is important that the diameter is opened with a smaller diameter d2a and the final diameter d2b (1/6 to 1/2 of the spinneret diameter) is obtained after the yarn is dropped.

Further, a shutter 7a is further provided below the yarn outlet portion of the reheating device 7 so that a desired yarn outlet diameter d can be obtained.
It may be 2b. In any case, it is necessary to restrict the yarn outlet to the heating device or the reheating device from the accompanying flow carried in by the yarn in order to suppress the decrease in the ambient temperature, and the accompanying flow that the yarn carries downward is discharged as much as possible. Since the amount becomes small, the air resistance at the yarn outlet increases, and the drawing action is also enhanced.

Further, even if a narrowed shutter is provided under the reheating device, there is no temperature drop, and therefore it was almost the same as the ambient temperature T2 of the reheating device. Also, the yarn outlet is preferably circular, but it may be in the shape of a square, the material is preferably ceramic, and it may be metal with a satin finish so that it does not come into contact with the unfocused yarn guide when it is focused. You can set it to

[0041]

EXAMPLES The present invention will be described in more detail below with reference to examples. The stains described in Examples and Comparative Examples are visually determined. The higher the dyeing score, the higher the product value, and 3.0 or more can be shipped as a product without problems. Naturally, unstretched products cannot be shipped. As a comprehensive judgment, judging from these stains, physical properties of yarn, and process condition, it was judged as ◎, ○, △, ×, and ◎, ○ were set as the production range.

[0042]

Examples 1 to 6 Polyethylene terephthalate having an intrinsic viscosity of 0.64 and a titanium oxide content of 0.3% by weight was discharged from a melt spinneret at a melting temperature of 295 ° C. using a device as shown in FIG. Table 1 shows the physical properties when a polyester fiber having a total denier of 75 denier and a single fiber denier of 1 and 3 denier was obtained.

At this time, the diameter of the spinneret was 64 mm, the diameter of the heating device was 35 mm, and the length was 1 m. The diameter of the yarn outlet of the reheating device was 5 mm.
The product was obtained by changing the ambient temperature of the heating device and the reheating device and the spinning take-up speed in mm. With respect to the products of Examples 1 to 6, there were few problems in the physical properties of yarn and production, particularly yarn breakage in the process, and there was no problem.

[0044]

[Comparative Examples 1 to 6] Products having the same melting temperature and the same total denier and single fiber denier as those of Examples 1 to 6 were obtained by changing the ambient temperature of the heating device and the reheating device. When the ambient temperature was low, the physical properties of the yarn were poor, and unstretched spots such as dye spots were generated, which was not preferable. In Comparative Example 6, the ambient temperature of the heating device and the reheating device is T1 respectively.
Is 250 ° C. or higher and T2 is set to T1 + 50 ° C. or higher, but the temperature is too high, so that the yarn swaying phenomenon remarkably increases in the heating device, and the number of filament breakage increases rapidly, which is not preferable. .

[0045]

Examples 7 to 9 The same spinning conditions as in Example 5 were used, and the diameter of the heating device and the diameter of the yarn outlet of the reheating device were changed to obtain products as shown in Table 2.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

As described above, according to the present invention, the spinning take-up speed is 7,000 m / min or more without direct spinning, and moreover, as compared with the separate-drawing and direct-drawing methods which are the production spinning techniques of polyester fiber. In the weaving process, there is a remarkable effect that polyester fibers that can be directly used in a woven or knitted product of direct yarn production, which has a low production cost and has no problem in quality, can be obtained.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram suitable for carrying out the present invention.

FIG. 2 is an explanatory diagram of a reheating device unit in FIG.

[Explanation of symbols]

 3 Cooling device 4 Heating zone 5 Jacket 6 Heating device 7 Reheating device 8 Thread exit 9 Oil agent applying device 13 Winder

Claims (2)

[Claims] 1. Atmosphere temperature T1 of a non-focused yarn obtained by melt-spinning polyester and then once cooling and solidifying the polyester is 120.
When heating while traveling in the heating zone of the cylindrical heating device kept at ˜250 ° C., the heating device outlet is narrowed down and the ambient temperature T2 at the heating device outlet is T1 + 50 to 1
A reheating device maintained at 00 ° C was installed and a spinning speed of 3500
A method for producing a polyester fiber, characterized in that the polyester fiber is taken up at a speed of m / min or more and taken up without stretching. 2. A cylindrical heating device is provided within 1.5 m below the melt spinneret, and the inner diameter of the cylindrical heating device is 2/5 to 1/1 and the length is 0. 5-1.
The method for producing a polyester fiber according to claim 1, wherein the yarn passing diameter of the reheating device at the outlet of the heating device is 5 m and is 1/4 to 1/15 of the outer diameter of the spinneret.