JPS62238816A - Spinning of polyester yarn - Google Patents

Abstract

PURPOSE:To obtain polyester fibers, having mechanical and thermal properties usable for weaving and knitting and capable of exhibiting latent crimps, by quenching discharged filaments with a liquid at a specific position and spinning a polyester under good spinning condition at a high speed. CONSTITUTION:In high-speed spinning of a polyester at >=6,000m/min-<9,000m/ min, discharged filaments 1 are quenched with a liquid fed from a quenching device 3 at a position within the range of 5cm on the upstream side of the end point of thinning to 3cm on the downstream side, preferably 5cm on the upstream side to the end point of thinning. In order to quench the filament group in an unbundled state, the group is quenched with the (quenching) liquid jetted from plural extrusion holes. Furthermore, quenching can be carried out by applying the quenching medium, oiling agent, etc., while bundling the filaments.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for high-speed spinning of polyester, and more particularly to a high-speed spinning method for improving spinning stability when spinning polyester at high speed.

<Prior art> When polyester such as polyethylene terephthalate is melt-spun and the take-up speed is increased, the molecular orientation of the taken-up yarn increases and crystals are formed, making it possible to obtain practically sufficient properties through the spinning process alone. Fibers with (
For example, see Japanese Patent Publication No. 35-3cm04, Journal of the Japan Institute of Fiber Science, Vol. 33, pages 208-214). According to these, in the case of polyethylene terephthalate, for example, when the take-up speed is about 5000 m/min or more, the fiber obtained becomes similar to conventional drawn yarn.

However, when the take-off speed is increased, particularly to a speed above 6000 m 2 /minute yield, on the other hand, frequent breakage of single fibers occurs during spinning, which significantly deteriorates operability.

This tendency becomes more pronounced as the single filament denier of m-fibers becomes smaller and the number of filaments increases.
), if the number of filaments (10 or more), 6000 m'
Spinning at speeds higher than 1/min becomes extremely difficult.

As a means to solve this problem, there is a method of suppressing oriented crystallization that progresses during high-speed spinning. For example, by increasing the ambient temperature under the cap and making the heat retention zone long to suppress molecular orientation, or by adding, blending, or copolymerizing some substance to the base polyester, polyimide, etc., the rate of crystallization progresses. Examples include methods to suppress this. However, according to the studies of the present inventors, these methods are effective for high-speed spinning of up to 700,077 L/min, and favorable results cannot be obtained for ultra-high-speed spinning at higher speeds. It turned out that there was no.

As the spinning take-off speed increases, crystal growth becomes significantly faster. Therefore, more effective means are required to suppress oriented crystallization.

A recently proposed method for this purpose is to apply water or oil to the running yarn during high-speed spinning to rapidly cool it (for example, Japanese Patent Application Laid-open No. 169513/1983).

(See No. 58-136816, No. 58-208416, No. 59-1573cm8).

Here, in the case of JP-A-58-169513 8-, a quenching bath is placed at a position where the discharged filament is still in an amorphous state, and at this time, the fresh water shrinkage rate is as high as 45% or more. Highly oriented amorphous fibers are obtained. Although this fiber can be used as a raw yarn for false twisting, it cannot be immediately provided as it is for knitting purposes.

Next, in the case of Japanese Patent Application Laid-Open No. 58-136816, the fibers are focused by a lubricating nozzle guide at a position within 1 TL below the spinneret surface, and oil is supplied, and this focusing.

Although it is preferable that the oil supply position be close to the spinneret, it is stated that the position should be selected so that breakage of soft fibers will not occur during the fiber formation process. Also, JP-A-58-20 which includes the same inventor
The invention of Publication No. 8416 has the same purpose, but the focusing and lubricating position is 5 points from the point where the filament group has completed thinning.
If a group of filaments is focused at a downstream region of more than 5 cm but less than 5 cm downstream from the point at which thinning is completed, the filaments will come into contact with each other at a position upstream from the point at which thinning is completed, making the spinning situation unstable and causing frequent breakage of single filaments. It is stated what to do.

However, according to the studies of the present inventors, when the take-up speed during spinning becomes extremely high, such as 8000 m/min, the effect of improving the spinning condition will hardly be recognized by the above-mentioned focusing and cooling. found. According to the findings of the present inventors, in such cases, the crystal growth rate is extremely high, so even a slight difference in the cooling position results in a large difference in the spinning condition. Furthermore, it has been found that it is not necessarily preferable to bundle multifilaments in such ultra-high speed spinning.

Further, in the case of JP-A-59-1573cm8@, a method is described in which the birefringence of a double cut filament is focused and lubricated within 30α downstream from the point where 0 increases most rapidly. However, in this case as well, the range of cooling positions is wide as in the above method, and knowledge necessary for specifying the cooling position necessary for controlling crystal growth necessary for improving spinnability in ultrahigh-speed spinning has not been obtained.

Further, although these applications state that it is necessary to bundle the multifilaments, it has been found that in the case of cooling ultra-high speed spun filaments, it is preferable not to bundle the filaments.

<Objects of the Invention> The first object of the present invention is to provide a spinning method that solves the problems of the conventional method and exhibits good spinning condition even in ultrahigh-speed polyester spinning.

Another object of the present invention is to provide a method for producing polyester fibers that have mechanical and thermal properties that can be used for woven or knitted fabrics in the as-spun and spooled state, and that exhibit appropriate apparent crimp. be.

<Configuration of the Invention> According to the present invention, when polyester is spun at a high speed of less than 9000 m/min in terms of yield of 6000 m/min,
3cm from the 5clIl upstream of the end point of the ejected yarn
Provided is a method for spinning polyester yarn, which is characterized by cooling with a liquid in the downstream range.

The polyester in the present invention refers to polyethylene terephthalate and polybutylene terephthalate.

It refers to so-called aromatic polyesters such as polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, and polyhexamedylene terephthalate, with polyethylene terephthalate being particularly preferred. In addition, in the polyethylene, an organic compound may be added in an amount of 10% by weight or less depending on various purposes.

There is no problem even if inorganic low molecules or polymers are blended or copolymerized.

In the case of the present invention, 900077L of 6000m/min or more
High-speed spinning at take-off speeds of less than /min is of interest. 600
0T! When the take-up speed is less than L/min, the spinning condition is good even without applying the present invention. On the other hand, 9000m,
/It is extremely difficult to manufacture and maintain the winding device for ultra-high-speed spinning for fractional spinning.

During high-speed spinning of polyester, the molten filament becomes finer as it cools. In the case of the present invention, the ejected yarn is 3 cm downstream from the 5 ctn upstream of the thinning end point, preferably 2 cm downstream from the 5 ctn upstream, more preferably 5 ctn.
It is necessary to cool with liquid in the range from the CIR upstream to the end point of attenuation. In one aspect of the present invention, the end point of thinning is determined as follows. That is, one filament with a diameter is taken out from among the multifilaments in the process of spinning and thinning, and its diameter is determined by Zimmer (West Germany).
Oiameter-Monitor460A/
Measured according to 5. Analog data from the measuring instrument is A
The data is converted into digital data by a /D converter, and further processed by a computer as a frequency distribution curve of diameters.

The most frequent point of the frequency distribution curve is taken as the fiber diameter at the measurement point.

By repeating this measurement along the spin line, a thinning curve can be obtained.

The thinning end point is the point at which the fiber diameter in the above thinning curve becomes 1.1 times the monofilament fiber diameter of the wound yarn. FIG. 1 illustrates various spinning speed thinning curves.

In the present invention, it is preferable that the traveling filament group be cooled without converging. Of course, convergence may be used, but when the number of filaments increases, there is a concern that the filaments may come into close contact with each other upstream of the cold W position and break.

However, after the above cooling is performed, there is no problem in applying focusing, cooling, oiling, etc. below. In particular, focusing the filament cooling within 10 cm downstream of the cooling point is effective in stabilizing the thread path of the primary cooling and compensating for any deficiency in the primary cooling.

The temperature of the cooling liquid in the present invention may be air temperature, but may be 5°C.
It is more effective to maintain the temperature below. The colder the temperature of the cooling liquid, the more effective it becomes.

In the present invention, cold N used to cool the discharged yarn
One embodiment of the device is shown in FIG.

2(a) and (01) respectively show a perspective view and a plan view of the cooling device, in which the discharge thread 1 passes through the hollow annular portion 2 of the cooling device, and at this time, It is cooled by the cooling medium ejected from each ejection hole 5 of the medium guide tube 4. Note that 6 is a supply conduit for the cooling medium.The cooling medium may be ejected from a single ejection hole, but it is not concentrated. In order to uniformly cool the filament group in this state, it is possible to achieve more uniform cooling by discharging the cooling liquid from the discharge holes of the number 'lri' as shown in FIG.

Further, FIG. 3 is a perspective view of a cooling device suitable for applying cooling medium, oil, etc. while converging discharged yarns 1 that have been cooled. 7 is a main body of the device, and a jet pipe 10 is provided through a supply conduit 9 to a focusing section 8.
Preferably used in oiling method.

In the present invention, it is more preferable to apply an oil agent at the same time as the cooling. In this case, the advantage is that there is less friction between the cooling device and the running filament.

Effects and Effects> According to the present invention, a high-speed spinning method with excellent spinning stability is provided even in high-speed take-off of 6000 m 2 /preparation.

This effect is estimated to be as follows based on the simultaneous analysis of the fiber structure development process during spinning.

In other words, according to this analysis, polyester drawn at a high speed of 6,000 m/min or more exhibits rapid thinning called "necking" in a part of the spinning line, and as this ends, the fiber diameter in the wound state decreases. reach

However, the formation of crystals begins to proceed at the same time as this change in l-fiber diameter ends. First, aromatic rings are stacked due to interaction between dipoles, and in the case of polyethylene terephthalate, what appears to be a crystal nucleus is generated in the a-axis direction. The rate of scooking of this aromatic ring becomes more pronounced as the spinning take-up speed is higher, and as the aromatic dipole effect becomes stronger, such as with naphthalene rings than with benzene rings, but in general, the rate of subsequent crystal growth increases. It's noticeably faster in comparison.

Next, the crystal grows with bending of the molecular chains. In the case of polyethylene terephthalate, this growth occurs equally along both the a and b' axes. This growth rate is slightly slower than the previous rate of crystal nucleation,
It may also be involved up to 20 to 30 α downstream from the end point of necking-like thinning. Of course, the growth rate also depends on the spinning take-off speed; for example, in the case of 6000 m/min, crystal growth continues from the thinning end point to about 20 G downstream, but 80 m/min.
At 00 m/min, crystal growth is completed up to about B crn downstream, and at 90 QOm/min, crystal growth is completed up to about 5 cm downstream. The growth rate also changes depending on the rigidity of the molecular chain, modification by copolymerization, etc., and generally becomes slower in these cases.

By the way, the stability of high-speed spinning is largely related to the formation of these crystals. Crystals of a certain size are essential for providing thermal stability to the wound fiber, but crystals that develop larger than necessary can cause stress concentration during the high-speed spinning process, resulting in single fiber breakage and breakage. It will start producing threads.

Therefore, when spinning at high speeds, it is desirable to suppress crystal growth as much as possible. To this end, it is generally desirable to cool rapidly after the crystal nucleus is generated or at the initial stage when the crystal is about to grow.

If the quenching occurs before nucleation, the pulled fibers will be highly oriented amorphous and will no longer be normal usable yarns. On the other hand, if the quenching position is at or after the middle stage of crystal growth, it becomes difficult to suppress crystal growth, which becomes more rapid as the speed becomes ultra-high.

For this reason, in the present invention, the discharged yarn is cooled with liquid between 5 cm upstream and 3 cm downstream of the thinning end point, preferably from 5cIR upstream to 21 downstream, and more preferably from 5 cm upstream to the thinning end point. .

Note that cooling the discharged yarn upstream after the completion of thinning has the following advantages. In other words, the necking position generally moves up and down considerably along the spinning line, so if cooling occurs downstream of the thinning end point, when the necking device shifts upstream, the cooling position will relatively move downstream too much. There is a risk that it will happen. In this case, the effect of suppressing crystal growth becomes small. On the other hand, when cooling is performed upstream of the thinning end point, the position of the necking thinning end point is fixed near the cooling device,
Vertical fluctuations become smaller. In other words, the stability of the cooling device is maintained.

The high speed spun fibers obtained according to the present invention are crystallized. Therefore, it is thermally stable, and for example, the shrinkage rate of fresh water is 1
Becomes 0% or less.

Furthermore, the high speed spun fibers wound in the present invention generally have crimps. This crimp becomes stronger and thinner as the spinning filament is cooled further upstream or cooled with a liquid having a lower liquid temperature.

Example 1 Intrinsic viscosity [ηcC is 0.63, and Ti02 is 0.63.
After drying polyethylene terephthalate containing 1% (to) 03ff with hot air at 160°C for 4 hours, it was discharged from a spinneret having 24 round holes with a nozzle diameter of 0.35 m at a spinning temperature of 3 cm and 0°C. The discharge filament is at the bottom of the nozzle 1.
It was cooled by cross-blown cooling air at a wind speed of 20 cttr/sec between 0 and 90[alpha], and wound up in a winder located 3 m below the mouthpiece. The take-up speed at this time was 8500 m/min, and the obtained multifilament was 75 de/24 f.
(Sample A).

Next, take out one filament from the group of 24 filaments,
Changes in fiber diameter along the spinning line were measured using an outer diameter measuring device manufactured by Z1O1ner. As a result, it was found that the end point of necking-like thinning was 78 CIR below the cap on average.

Next, the cooling devices shown in FIG. 2 were installed at various positions under the cap to rapidly cool the running multifilament. As the cooling medium of this quenching device, an emulsion of ice water (water temperature: 3° C.) and spinning oil was used for samples B to G).

Table 1 shows the crystal size (a, b axis direction), fresh water shrinkage rate, and crimp occurrence of samples A to G obtained as described above, together with the spinning condition.

(The following is a margin) In the case of the sample, no special cooling was performed during the spinning process, and the spinning condition was extremely poor, and single yarn breakage occurred within a few seconds, followed by yarn breakage.

On the other hand, in the case of sample B, since the cooling position was located too far upstream compared to the necking thinning end point (78cIR), the filaments came into close contact with each other upstream of the cooling device, further worsening the spinning condition. In the case of sample G, on the contrary, since the cooling position was too far downstream, there was almost no effect of suppressing crystal growth and the spinning condition was not improved.

In contrast to the above, in the case of Samples C-F, a clear improvement in spinning condition was observed. Among them, especially in samples C and D where the cooling position was upstream, the improvement in spinning condition was remarkable.

In these samples with good spinning condition, the crystal size is smaller than that of Sample A or G, and the fresh water shrinkage rate is on the contrary increased.

In other words, suppression of crystallization is effective. This is particularly noticeable in samples C and D, which are well-spun.

In the case of sample B, almost no crystal formation was observed, and the fresh water shrinkage rate was significantly higher than that of the other samples. In this case, it is considered that the fiber structure is actually highly oriented and poor quality.

Further, in Samples B, C, and D, the wound yarn exhibited strong crimp, but in Samples A, E, F, and G, almost no crimp was observed.

* The crimp was evaluated by the following method described in Japanese Patent Application Laid-Open No. 58-54035.

Based on the bulk of ordinary spun and drawn yarn (flat yarn), those 3 to 4 times the bulk of this are ``Large'', 2 to 3 are ``Medium'', and those 1 to 2 times are ``No''. It was ゛゛.

Measurement of bulk height 0.64 g of yarn was placed in a box (height 2.5° width 1.0
cm, width 10aR, bottom surface 0, radius of curvature of 5 Crn) is filled, and under the load of the lid (weight 69), the volume (Vci) of a constant value of yarn (W9-0.649) is as follows. Calculated using the formula.

Bulk height (c#i/9) = V/W Comparative Example 1 In Example 1, instead of the cooling device shown in FIG. 2, a cooling device as shown in FIG. 3 was used to collect and cool the multifilament. did.

When the cooling device was placed at a position corresponding to Samples B and C of Example 1, the multifilaments tended to adhere to each other, making spinning impossible. At the positions corresponding to samples D and E, spinning was possible for several tens of seconds, but yarn breakage soon occurred due to close contact. At the position of sample E, spinning for several minutes was possible. However, when focusing and cooling at a position corresponding to sample G, the spinning condition deteriorated again, with single yarn breakage occurring within a few seconds.

Example 2 The cooling device shown in FIG. 2 was installed corresponding to Example 1 Sample C, and the cooling device shown in FIG. . In this case, the spinning condition was good and complete winding was possible in 30 minutes.

Example 3 Sample D1. When the cooling medium was changed to room temperature water (water temperature 25°C) and hot water (water temperature 50°C), the results shown in Table 2 were obtained.

Table 2 shows that as the coolant temperature increases, the crystal size increases and the spinning condition tends to deteriorate slightly.

[Brief explanation of drawings]

FIG. 1 is a graph showing an example of a thinning curve of a discharged filament (take-up speed of 5,000 to 10,000 m/m) when the present invention is carried out. Figures 2 and 3 are a perspective view (a) and a plan view (01) showing an example of the cooling device according to the present invention. 3.7...
Main body, 4...-guide pipe 5... nozzle hole, 6.9... supply conduit 10...
Ejection pipe, 8... Focusing section discharge m6.2 g/min,
-1 0 Distance from gold (cm)

Claims (7)

[Claims] (1) Polyester at 6000 m/min or more 9000 m/min
A method for spinning polyester yarn, which comprises cooling the discharged yarn with a liquid in a range from 5 cm upstream to 3 cm downstream of the thinning end point during high-speed spinning at a take-up speed of less than 1 minute. (2) The polyester yarn spinning method according to claim (1), wherein the discharged yarn is cooled with liquid in a range from 5 cm upstream to 2 cm downstream of the thinning end point. (3) The method for spinning polyester yarn according to claim (1), wherein the discharged yarn is cooled with liquid in a range from 5 cm upstream of the end point of attenuation to the end point of attenuation. (4) The polyester yarn spinning method according to any one of claims (1) to (3), wherein the discharged yarn is cooled with a liquid without being bundled. (5) Within 10 cm downstream of the cooling point by the liquid,
The polyester yarn spinning method according to claim (4), wherein the discharged yarn is bundled and cooled with a liquid. (6) The method for spinning polyester yarn according to any one of claims (1) to (3), wherein the temperature of the cooling liquid is 5°C or less. (7) A method for spinning polyester yarn according to claims (1) to (5), in which the discharged yarn is cooled and oiled at the same time.