JPS5842286B2 - Fine denim polyester fiber and its manufacturing method - Google Patents

Description

Detailed Description of the Invention The present invention provides a novel fine denier polyester fiber with a single filament denier of 0.7 d or less, and a novel manufacturing method for producing the fine denier polyester fiber using a conventional single-component melt spinning method with good spinning operability. Regarding.

Suede-like fabrics made from fine denier polyester fibers with a single yarn denier of 0.7d or less, or georgette and crepe-like fabrics using strong twist yarns have an excellent appearance and feel, so their uses are rapidly expanding recently. There is a tendency to

When attempting to produce fine denier polyester fibers with a single yarn denier of 0.7d or less using a normal single-component melt spinning method, significant yarn breakage occurs during the spinning and drawing processes.
Since it was practically impossible to produce commercially using such a method, conventionally, the special spinning method described below was used for manufacturing.

The special spinning method that has been used in the past is, for example,
After obtaining sea-island fibers as shown in Japanese Patent Publication No. 4-18369, ultrafine fiber bundles are obtained by dissolving sea components, or after obtaining multi-divided fibers as shown in Japanese Patent Publication No. 48-28005. This is a spinning method such as a method in which ultrafine fiber bundles are obtained by applying a peeling treatment.

However, these methods require equipment for composite spinning of at least two precept polymers, and require post-processing such as dissolution treatment and peeling treatment, which inevitably increases manufacturing costs and increases the manufacturing process. However, it also had the disadvantage of being complicated.

Therefore, the present inventors conducted research on a method for obtaining polyester fibers with a single yarn denier of 0.7 d or less using a normal single-component melt spinning method, and as a result, polyester fibers with a single yarn denier of 7 d or less were obtained. When attempting to do so, it became clear that it was necessary to significantly reduce the discharge amount per spinneret hole in the spinning process, or to significantly increase the yarn take-up speed during spinning. It is clear that the discharge condition of the strand becomes extremely deteriorated, resulting in a so-called raindrop phenomenon, which leads to yarn breakage or streaks during spinning.

It was found that this rain dripping phenomenon could be resolved by shortening the distance between the spinneret surface and the top end of the cooling air blowing surface. Although the yarn is cooled quickly and the dripping phenomenon is eliminated, a new problem arises in that the discharged yarn is cut during layer 1.

The inventors of the present invention conducted further intensive research to solve the above problem, and found that polyester polymers with a melt viscosity of 1,450 poise or higher when heated to 290°C, which are normally used for clothing, cannot be extruded from a spinneret. It is not possible to follow the rapid deformation speed immediately after, causing brittle fracture of the yarn, but it was discovered that this problem could be solved by using a polyester polymer with a lower melt viscosity, and the present invention was made based on this discovery. reached.

The first invention of the present application is a fine denier polyester fiber characterized in that a single yarn denier D is 0.7 d or less and a melt viscosity η290 at 290° C. satisfies the following formula (I).

450≦'7290≦s 20 D+ s 40-...
-<I) [In formula (I), η290 represents the melt viscosity (poise) at 290°C, and D represents the single filament denier of the drawn yarn.

], and the second invention is to melt-spun a fiber-forming polyester polymer through a spinneret, cool it by blowing a cooling air stream onto the spun yarn directly below the spinneret, and then continue spinning. In a method for producing fine denier polyester fibers with a single filament denier D of 0.7 d or less by drawing and drawing or drawing after drawing, melting of the polymer at 290 ° C. when passing through a spinneret. Viscosity η290
This is a method for producing fine denier polyester fibers having a single yarn denier of 0.7 denier or less, which is characterized in that the method satisfies the following formula:

450≦'7290≦820 D+ 840-・-・-
- (I) [In formula (I), η290 represents the melt viscosity (poise) at 290°C, and D represents the single yarn denier of the drawn yarn.

[The polyester fiber of the present invention is made of a fiber-forming polyester mainly containing ethylene terephthalate units, especially a fiber-forming homopolyester or copolyester containing 85 or more moles of ethylene terephthalate units, or a mixture thereof. Melt viscosity η2. It is a fine denier fiber with a single yarn denier of 0.7 d or less, % [0.1 to 0.5 d], which shows the value shown by the formula (MidI).

The melt viscosity η290 at 290°C, which is detrimental to the present invention, is
This is a value obtained by measurement by the method described below, and is different from the intrinsic viscosity IV that has been commonly used in the past.

Although a specific method for producing fine denier polyester fibers with a drawn yarn having a single filament denier of 0.7 d or less with good spinning operability using a normal single-component melt spinning method has not been proposed, the present inventors have conducted extensive research. As a result of stacking, the melt viscosity of the polymer at 290°C when passing through the spinneret η2. .

It has been found that when the above-mentioned formula I) is satisfied, such fine denier polyester fibers can be produced with good spinning operability and drawing operability by a conventional single-component melt spinning method.

The melt viscosity η2QO of the polymer when passing through the spinneret is
The reason why yarn breakage in the spinning process of fine denier polyester fibers is reduced and spinning operability is improved when the conditions specified by formula I) are satisfied is not clear at all, but when the melt viscosity is low Alternatively, it has been found that when the molecular weight of the polymer is low, it becomes easier to follow deformation at a high deformation rate.

This is explained by the short relaxation time of the polymer when it undergoes deformation.If the relaxation time is short, even if the deformation rate is high, the yarn can sufficiently follow the deformation without brittle failure. It seems likely.

The deformation rate can be evaluated by measuring the change in yarn diameter by some means during the process 1 after the polymer is discharged from the spinneret until solidification is completed (the present inventors used laser interferometry). If the normal discharge rate per hole is about 11/min (measured by
Even if it is as high as 000rrL/min, the maximum value of the deformation rate is at most 5008ee-1.

However, even if the take-up speed is about 1300 m/min, if you want to obtain a single yarn denier of 0.7 d or less, especially 0.5 d or less, the discharge amount per hole will be 0.3 t/min.
min, and the maximum deformation speed is 1000 se
c 'Eventually, it will exceed 2000 sec'.

If a fine denier fiber with the same single filament denier is obtained at a lower take-off speed during high-speed spinning, the output per hole will be higher, but the deformation rate will be higher due to the higher take-off speed.
It tends to become more expensive.

In the case of polymers with high intrinsic viscosity, it is possible to lower the melt viscosity during spinning by spinning at a higher temperature.
In this case, there is no effect on reducing thread breakage, and even the diameter is 290
The present inventors have found that it is necessary to keep the melt viscosity η290 at a certain level low in order to reduce yarn breakage.

On the other hand, if the melt viscosity is too low, variations in yarn diameter and yarn properties between filaments will become too large during the spinning process.
Yarn breakage occurs frequently due to the knealing phenomenon, and yarn breakage occurs frequently during the drawing process due to lower fiber strength.

Therefore, the η290 of the polymer when passing through the spinneret must be at least 450 poise, and in order to reduce the number of yarn breakages due to brittle fracture and to obtain yarn with good spinning operability, the η290 must be at least 450 poise.
The upper limit of 290 depends on the single yarn denier D of the finished yarn (drawn yarn) (820D+840>poise or less, especially (1000D)
It is necessary to keep it below D+701 poise.

The melt viscosity range of the present invention expressed by the aforementioned formula σN is shown in FIG.

The area surrounded by diagonal lines in FIG. 1 is the area that satisfies the requirements of the present invention.

The melt viscosity of polyester fibers and polyester polymers can be measured using a capillary viscometer or rotational viscometer that is normally commercially available. ) in a nitrogen atmosphere.

The measurement sample was about 30 f of polyester fiber (undrawn yarn or drawn yarn), which was deoiled and dried, then melted at 290° C., and measured at a rotor rotation speed of 2.

pm For samples that undergo thermal decomposition in the molten state and whose melt viscosity decreases over time, the sample should be heated for 2 minutes or 3 minutes from the point of complete melting.
The melt viscosity after 4 minutes and 4 minutes was read, and the value obtained by extrapolating these values to 0 minutes was defined as the melt viscosity η290 at 290°C.

Note that the melt viscosity decreases slightly due to thermal decomposition occurring from the time the polymer is melted in the spinning process until it reaches the spinneret, but does not change after passing through the spinneret.

Therefore, the η290 values of the undrawn yarn and the drawn yarn are the same, which also coincides with the η290 value of the polymer as it passes through the spinneret.

The melt viscosity can be measured at any temperature as long as it is above the melting point of the polymer, but as long as the fiber is made of polyethylene terephthalate as its main component, the temperature dependence of the melt viscosity will not change significantly. They selected a measurement temperature of 290°C because it was easy to measure and had good accuracy.

Incidentally, the present inventors have experimentally confirmed that the relationship between the melt viscosity η (whiz) of a polyethylene terephthalate polymer and the measurement temperature TO is expressed by equation (2).

(In the formula, C represents a constant) η2. -1 Its intrinsic viscosity ■v and diethylene glycol content in the fiber DEC (mo1%)
It was also experimentally confirmed that the intrinsic viscosity is approximately determined by the equation (3). This is the measured value, and the diethylene glycol content D'EG
(mol %) - Using a gas chromatograph G8 model manufactured by Yanagimoto Seisakusho Co., Ltd., sample fibers were diluted with methanol.
This value is expressed as the molar ratio of diethylene glycol to ethylene glycol, based on the peak area ratio of ethylene glycol and diethylene glycol in a measurement sample decomposed at 50°C.

] The η290 of the polymer when it passes through the spinneret is
) Formula can be easily satisfied by appropriately selecting the intrinsic viscosity IV and/or diethylene glycol content DEG molar range of the polymer from the relationship of the above-mentioned formula 3) when polyethylene terephthalate is used. It can be done.

In this case, it is necessary to take into account to some extent a decrease in the degree of polymerization due to thermal decomposition between the time the polymer is melted and the time it reaches the spinneret.

Further, the intrinsic viscosity and diethylene glycol content can be changed by appropriately selecting polymerization conditions.

DECH in polyethylene terephthalate, which has conventionally been generally subjected to melt spinning, is about 0.1 to 1.5 moles wide.

For reference, the relationship between the intrinsic viscosity IV of polyethylene terephthalate fibers having a value of η290 of 300 to 1400 poise and the diethylene glycol content DEC (mole cup) is shown in the second table.

As is clear from FIG. 2, even if IV is high, if DEC is large, η290 becomes low.

However, if the amount of DEC is excessively increased, the color fastness of the fiber will decrease, so it is preferable to select it within the range of DEC≦10 molar ratio.

In the case of polyester fibers other than polyethylene terephthalate fibers, formula 3) does not hold, but if the intrinsic viscosity of the polymer is reduced, the value of η290 generally becomes smaller.

However, depending on the type of polymer (for example, differences in copolymerization components, copolymerization ratio, etc.), η2. .

Since the values of .eta.290 and .eta. vary considerably, it is necessary to appropriately select polymerization conditions in advance so that the value of .eta.290 satisfies the equation (Maegota) depending on the type of polyester used for spinning.

The amount of molten polymer discharged per spinning hole (also called single hole) naturally varies depending on the single fiber denier of the finished yarn to be obtained, but at 0.3 f/min per 1 hole, it is >2
-The finished single yarn denier is 0.7d.

Furthermore, for single yarns of 0.5 d, 0.3 d, and 0.1 d, the discharge amount per hole is 0.2 S'/min, 0.
1 f/m1nO,03? /min.

The discharge amount per spinning hole is 0.3 Si' /yliH
If an attempt is made to discharge from a conventional spinning hole with a large cross-sectional area at a low discharge rate, the discharge condition will become unstable and periodic fluctuations will occur in the length direction of the yarn thickness.

In order to suppress this periodic fluctuation, it is most effective to use a spinning hole with a small cross-sectional area corresponding to a low discharge rate, and according to the findings of the present inventors, periodic fluctuations in the length direction of the yarn thickness can be suppressed. The upper limit of the cross-sectional area of the hole that does not occur is 9.0, where the discharge amount per spinning hole is G (f/min). OXl, 0-2G3
(111il).

Filaments discharged from a spinning hole with a cross-sectional area larger than this exhibit clear thickness unevenness in the filament's length direction, resulting in yarn breakage during spinning and/or drawing, or yarn unevenness in the drawn yarn increases significantly. .

In terms of yarn unevenness, the smaller the cross-sectional area of the spinning hole, the better! However, if the cross-sectional area of the orientation is small, problems may occur due to excessive pressure loss in the spinning hole during polymer discharge, or surface roughness of the undrawn filament (so-called shark skin). Since spun yarn breakage and drawn yarn breakage occur, the lower limit is 4.5 x 10-2s10-2s.

Further, the length of the spinning hole is preferably such that the relationship with the circular diameter DC of the cross-sectional area of a single hole satisfies the following formula.

The spinning temperature must be carefully selected according to the properties of the polymer; if it is too high, a knealing phenomenon will occur and the spun yarn will break, while if it is too low, sharkskin will occur, causing trouble in the spinning and drawing processes. .

The spinneret surface temperature is at least 5°C below the melting point of the discharged polymer.
A temperature higher than the melting point of the discharged polymer, preferably 10-30°C.
When the temperature is maintained at a high temperature (°C), the spinning stability becomes extremely good, and the occurrence of spun yarn breakage, drawn yarn breakage, drawn fuzz, etc. is significantly reduced.

When melt-spinning fine denier fibers, the cooling rate of the spun yarn is fast, so each single fiber is rapidly cooled at its center by the cooling air flow.

Therefore, the distant cousin of uniform cooling in the cooling solidification process is important.

That is, the discharged yarn becomes a completely solidified yarn within a few 1 ocm directly below the spinneret, and an entrained flow of the yarn traveling to the take-up device 75 is rapidly formed.

Therefore, from this point of view, the height of the cooling air blowing surface should be as short as possible, and the distance between the uppermost horizontal surface of the cooling air blowing surface and the spinneret surface should be 5 to 50 mm, especially 10 to 35 mm.
The shorter the length (mm), the better.

The cooling air stream is preferably blown approximately perpendicularly to the spun yarn to achieve uniform cooling.

A known cooling method is used for the cooling air flow, such as a method in which the air is blown from one side of the yarn, a so-called circular quench method in which the air is blown in the circumferential direction, and a method in which the air is blown radially outward from the center of the yarn bundle. .

The blowing speed of the cooling air flow is approximately 0.1 to 0.8 m/see,
Preferably, it is 0.2 to 0.6 m/see.

The spinning speed is not particularly limited, but is usually 500 to 2500 m.
/min, especially 1000 to 1500 m/min.

In the case of an improved spindle type as described in JP-A-51-123319, etc., the spinning take-off speed is about 6000 m/min.

It is possible to a degree of 1.

The shape (cross section) of the spinning hole is most commonly circular, but it may also have a Y-shape, C-shape, ■-shape, or other irregular cross-sections other than circular.

Further, there is no particular restriction on the number of spinning holes.

In the present invention, it is of course possible to interlace the yarn between the spinning take-up tubes.

When subjecting the yarn to the stretching process after it has been wound up in the spinning process, the stretching temperature button and stretching ratio should be approximately the same as in the case of conventional multifilament yarns or tows with a single filament denier of 1 to 5 d after stretching. However, in the case of fine denier fibers, the pre-orientation during spinning is large, so the draw ratio needs to be much lower than conventional ones.

The fine denier multifilament yarn obtained according to the invention provides a fabric with a unique hand when used as a high twist yarn.

It is also possible, of course, to bundle a large number of fibers into a tow, draw them, cut them into short fibers, and use them as staples, or to use them as non-woven fabrics.

In particular, fine denier fibers with a single yarn denier of 0.5 d or less are useful when knitted or woven and put to practical use as suede base fabrics.

Next, the present invention will be further clarified by examples.

Example 1 Eleven types of polyethylene terephthalate polymers having various melt viscosities when passing through a spinneret were produced by changing the diethylene glycol content (DEG mole φ) and the intrinsic viscosity IV, and these polymers were made into a polyethylene terephthalate polymer having a diameter of 0. Through a spinneret with 200 circular spinning holes of 12wn, 8S
'/min, 14 f/min, 34 r/min
Melt spinning was carried out at a spinning temperature as shown in Table 1 at a discharge rate of 60 f/min, and a cooling air stream at room temperature was applied to one side at a flow rate of 0.3 m/sec perpendicular to the spun yarn directly below the spinneret. The yarn was cooled and solidified by blowing the yarn.

The distance between the uppermost horizontal plane of the cooling airflow blowing surface and the spinneret surface was 17 m, and the length of the cooling zone by the cooling airflow was 50 cm.
And so.

After cooling, the yarn is treated with an aqueous oil emulsion using an oiling roller in a conventional manner, and then processed for 1300 m.
It was picked up at a speed of /min.

The undrawn multifilament yarn obtained by sniffing was then
A drawing and twisting machine equipped with a heating roller at 5°C and a hot plate at 135°C was used to draw and twist the yarn at a drawing speed of 60-VΩn at a drawing ratio such that the elongation of the finished yarn (drawn yarn) was 25 to 30 factors. did.

This example [i- Intrinsic viscosity of the polymer IV (measured at 30°C in a mixed solvent of phenol/tetrachloroethane = 614,
(same below), diethylene glycol content DEC (molder), spinning conditions (polymer discharge rate, spinneret surface temperature)
, spun yarn breakage, drawing ratio, stretched yarn breakage, physical properties of undrawn yarn or drawn yarn [denier, fluff level, intrinsic viscosity, diethylene glycol content DEC (mol %), η2. .

] are shown in Table 1.

As shown in Table 1, it can be seen that the fibers belonging to the present invention have less spun yarn breakage and drawn yarn breakage, and therefore can produce Fidenyl polyester fibers with good spinning and drawing operability.

On the other hand, those that do not belong to the present invention (shown as comparative examples) frequently break the spun yarn due to brittle fracture or knealing, and the spinning operation is extremely poor, making it difficult to satisfactorily obtain undrawn yarn that can be used in the drawing process. I couldn't do it.

Example 2 Manufactured by adding 2.3 molar amount of sodium 3.5-di(carbomethoxy)benzenesulfonate to dimethyl terephthalate as the third component. Intrinsic viscosity = 0.4
4 (measured in a mixed solvent of phenol/tetrachloroethane = 6/4 at 30°C) of ethylene terephthalate copolyester (2.0 mol ratio) was spun into a Y-shaped spinning hole (as shown in Fig. 3). a=120', a=b=0.0
Through a spinneret with 96 pieces (7 mm), a throughput of 15
．． 4 f/min, melt spinning at a spinning temperature of 280°C, and 0-
The yarn was cooled and solidified by blowing from one side at a flow rate of 3 m/see.

The distance between the uppermost horizontal plane of the cooling airflow blowing surface and the spinneret surface is 30y++m, and the length of the cooling zone by the cooling airflow is 5.
It was set to 0 crn.

After cooling, the yarn was treated with an aqueous oil emulsion using an oiling roller in a conventional manner, and then 1150
It was pulled at a speed of m/min.

The undrawn multifilament yarn obtained by sniffing was then
The yarn was drawn and twisted at a draw ratio of 2.46 times using a draw-twisting machine equipped with a heating roller at 0°C and a hot plate at 130°C to produce 49d/96 yarn.
f (single yarn denier D 20, 51d) elongation 32hong η29o
A fine denier polyester fiber with -lO50 poise and trilobal cross section was produced.

The spinning operability of this example Vci was extremely good, and there was no spun yarn breakage even once during continuous spinning for 6 hours.

Comparative Example A copolymerized polyester similar to that shown in Example 2 (however, the intrinsic viscosity was changed to IV = 0.48, DEG = 2.4 mol%, and η29o-1580 poise of the polymer when passing through the spinneret) was carried out. When melt spinning was carried out under the same spinning conditions as in Example 2, there were many spun yarn breakages, and continuous spinning could not be performed.

As a result of increasing the polymer discharge rate by 1- and searching for the lowest discharge rate at which the spun yarn would not break even once in 30 minutes, the discharge rate was found to be 24 f/min.

Therefore, the undrawn yarn obtained by spinning at this discharge rate was drawn at a draw ratio of 2.6 times using the same drawing and twisting machine as in Example 2, and the result was 72d/96f (single yarn denier D = 0.75d).
, η2. .

A polyester fiber of =1580 poise was obtained, but the single yarn denier of this polyester fiber was thicker than 0.7 d, and the elongation was as low as 14 modulus.

Example 3 A polyethylene terephthalate-isophthalate copolymer with an intrinsic viscosity of IV = 0.56, which was produced by adding dimethyl isophthalate by 11 moles to dimethyl terephthalate as the third command, was used in Example 1. It was extruded from the same spinneret at a spinning temperature of 275° C. and a discharge rate of 261/min, and drawn at 1300 m/min in the same manner as in Example 1, and then drawn to 2.72 times to obtain a single yarn denier of 0.33.
A fine denier polyester fiber having an elongation factor of 26 and an η29o of 970 poise was obtained.

In this example [i-, spinning operability and stretching/twisting operability were good;
No yarn breakage occurred during 6 hours of spinning and 3 hours of stretching.

Furthermore, the dyeability of the obtained fine denier polyester fiber was extremely high.

Example Polymerization: 11 mol of dimethyl isophthalate, 3.5-
A polyester copolymer with an intrinsic viscosity of IV=0.50 obtained by adding 1.5 mol of di(carbomethoxy)benzenesulfonic acid and IJum to dimethyl terephthalate was used in Example 2. It was extruded from the same spinneret at a spinning temperature of 278° C. and a discharge rate of 15.4 r/min, and spun and stretched in the same manner as in Example 2.

The obtained fiber has a single yarn denier of 0.5 d1 and an elongation of 28, η
2. .

= 760 poise. In the case of this example as well, the spinning/drawing operability was extremely good.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the single yarn denier D specified in the present invention and the melt viscosity η290 at 290°C, and Figure 2 is a graph showing the relationship between the intrinsic viscosity IV and diethylene glycol content DEC (mole coefficient) of polyethylene terephthalate fibers. 290℃
Graph showing the relationship with melt viscosity η290, Part 3
The figure is a plan view showing the shape of a Y-shaped spinning hole used in carrying out the present invention.

Claims (1)

[Scope of Claims] 1. A fine denier polyester fiber characterized by having a single yarn denier D of 0.7 d or less and a melt viscosity η290 that can be fired at 290° C. satisfying the flat ridge p formula. 450≦'7290≦820D+840 (I) [
However, in formula (I), η290 represents the melt viscosity (poise) at 290° C., and D represents the single yarn denier of the drawn yarn. 2. The fine denier polyester fiber according to claim 1, wherein the polyester fiber is composed of polyester mainly containing ethylene terephthalate units. Melt viscosity η2. The fine denier polyester fiber according to claim 1 or 2, which has an ob2450 poise or more and a (1000D+700) poise or less. 4. Melt-spun the fiber-forming polyester polymer through a spinneret, then cool it by blowing a cooling air stream onto the spun yarn directly below the spinneret, and then draw it continuously during spinning and take it off, or take it off once. The method for producing fine denier polyester fibers having a single filament denier D of 0.7 d or less by stretching the fibers after drawing is based on the melt viscosity η2. . A method for producing fine denier polyester fibers having a single yarn denier of 0.7 denier or less, characterized by satisfying the following formula. 450≦η290≦820 D + 840−・−・−
(ii) [However, in formula (I), η290 represents the melt viscosity (poise) at 290° C., and D represents the single yarn denier of the drawn yarn. 5. The method for producing fine denier polyester fibers according to claim 4, wherein the fiber-forming polyester polymer is a polyester mainly containing ethylene terephthalate units. 6. The method for producing fine denier polyester fibers according to claim 4 or 5, wherein the polymer has a melt viscosity at 290° C. of 450 poise or more and (1000D+700) poise or less when passing through a spinneret.