JP2001098415A - Method for melt spinning of polyamide fiber yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melt spinning method for nylon fiber yarn which can reduced tension of yarn after extruded from a spinneret under a condition that a solidifying point is lowered, uniformizes tensions of single fibers, prevents a processability decline due to the occurrence of draft-caused fiber rupture, etc., and enables fiber yarn excellent in uniformity to be obtained. SOLUTION: An atmosphere temperature in a heating hood 2 right under a spinneret 1 is set being (the melting temperature of a polymer minus 70 deg.C) to (the melting temperature of a polymer plus 50 deg.C). A warm air blowing apparatus 3 is installed directly under the heating hood 2. Melt spun yarn Y passed through the hood 2 are blown by warm air from the apparatus 3 which has a specific range of temperature determined by a single fiber fineness, the number of filaments, a draft value, a bundling position of yarn and the relative viscosity of a polymer chip in use and then are blown by cooling air showing <=20 deg.C to be cooled and solidified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for melt-spinning a polyamide fiber yarn, and more particularly to a method for reducing the occurrence of yarn spots and obtaining a fiber having excellent uniformity and good operability. is there.

[0002]

2. Description of the Related Art Generally, when performing melt spinning of polyamide, cooling air of 20 ° C. or less is blown from the outer periphery of the melt-spun yarn to solidify by cooling. In this case, the cooling air is heat-replaced by the yarn close to the blowing side and the yarn near the blowing side, and the temperature gradually increases. The temperature becomes uneven. As a result, the yarn formation due to cooling is different, and as a result, the tension acting between the yarns is different, so that the frequency of so-called draft breakage immediately below the base increases,
In addition, the yarn spots of the obtained yarn also become large.

[0003] Japanese Patent Application Laid-Open No. Hei 7-89025 discloses a method in which hot air of 50 ° C. or more is blown from one side before cooling air is blown to a polyamide yarn immediately below a melt-spun die. . However, with this method, depending on the brand, for example, when the fineness of the single yarn is large and the draft value is high, the solidification point is too low, and fusion between the single yarns may be induced.

Japanese Patent Application Laid-Open No. 55-67007 discloses a method in which warm air is blown in an area within a so-called heating hood within 10 cm immediately below a spinneret. However,
In this method, a hot air having a temperature lower than the nozzle temperature is blown in a region (within the heating hood) very close to the spinneret surface within 10 cm immediately below the spinneret, so that the spinneret surface is cooled, and yarn swaying and yarn breakage occur. This has the disadvantage that the operability deteriorates.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and can stably spin a yarn without changing the temperature of the spinneret surface, and can appropriately set the solidification point. By lowering, the tension of the yarn exiting the spinneret is reduced, the tension between the single yarns is made uniform, the operability is not reduced by the occurrence of draft cut, etc., and a fiber yarn with excellent uniformity is obtained. It is an object of the present invention to provide a method for melt-spinning polyamide fiber yarn.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.
That is, in the present invention, the atmospheric temperature in the heating hood immediately below the spinneret is set to (the melting temperature of the polymer minus 70 ° C.) to
(The melting temperature of the polymer plus 50 ° C.), a hot air blowing device is provided immediately below the heating hood, and the molten spun yarn that has passed through the heating hood is subjected to the following (1) to
A method of melt-spinning polyamide fiber yarns, comprising blowing hot air having a temperature satisfying any of (3) and then cooling and solidifying the yarn by blowing cooling air having a temperature of 20 ° C. or less. It is the gist. (1) When the relative viscosity of the polymer is 3.00 or less 2.5 × A ≦ Hot air temperature (° C.) ≦ 6.0 × A (2) The relative viscosity of the polymer is greater than 3.00 and after cooling and solidification When the distance between the yarn converging point and the lower surface of the spinneret is 2
When it is within 00 cm 2.5 x (relative viscosity / 2.50) ² x A ≤ hot air temperature (° C)
≦ 6.0 × (relative viscosity / 2.50) ² × A (3) The relative viscosity of the polymer is greater than 3.00, and the distance between the converging point of the yarn after cooling and solidification and the lower surface of the spinneret is 2
When it exceeds 00 cm 2.5 × (relative viscosity / 2.50) ² × (1 / 0.75) ×
A ≦ hot air temperature (° C.) ≦ 6.0 × (relative viscosity / 2.50) ²
× (1 / 0.75) The relative viscosity was determined by using 96% by weight sulfuric acid as a solvent and a concentration of 1
g / dl, measured at a temperature of 25 ° C., and A = (square root of filament number × common logarithm of draft value) / square root of single yarn fineness (d).

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. 1 and 2 are schematic explanatory views showing one embodiment of the melt spinning method of the present invention. In the method of the present invention, the spun yarn Y melt-spun from the spinneret 1 passes through the heating hood 2 immediately below the spinneret 1 and then from the hot air blowing device 3 provided immediately below the heating hood 2. Hot air is blown, and then cooling air having a temperature of 20 ° C. or less is blown from the cooling air blowing device 4 to be cooled and solidified. And
The yarn after cooling and solidifying is applied with an oil agent by the slit nozzle 5 as shown in FIG. 1 and is then taken out while being bundled, or as shown in FIG. To collect while focusing. In FIG. 1, the focal point is the position of the slit nozzle 5, and in FIG. 2, the focal point is the position of the take-up roller 6.

In the method of the present invention, both the hot air blown from the hot air blowing device 3 and the cooling air blown from the cooling air blowing device 4 to the melt-spun yarn Y are blown from one side of the yarn Y. 1 and 2 show a case where air is blown from one side. In this case, an exhaust duct 7 is provided on the opposite side of the air outlet 11 of the hot air blowing device 3 and a lower cooling air is blown. It is preferable that the cooling air blown from the device 4 onto the yarn be discharged quickly so that the temperature does not rise due to the warm air.

The hot air blowing device 3 and the cooling air blowing device 4 are connected to a common cold air duct 8.
It is preferable that the gas is heated by the heater 9 provided above the cold air duct 8 and the hot air is blown from the hot air blowing device 3.

In the present invention, first, a polyamide yarn Y is spun from a spinneret 1 into a heating hood 2. At this time, the atmosphere temperature in the heating hood 2 is set to (the melting temperature of the polymer minus 70 ° C) to (the melting temperature of the polymer plus 50 ° C).
And With such an ambient temperature, it is possible to prevent the yarn from swaying and breaking immediately below the spinneret surface without giving a temperature change to the spinneret surface.

If the temperature of the atmosphere in the heating hood 2 is lower than (the melting temperature of the polymer minus 70 ° C.), the surface of the base is cooled, the yarn sways, and the uneven and inhomogeneous fiber yarn is formed. Become. On the other hand, (Polymer melting temperature + 50
If the temperature exceeds (° C.), the surface of the die is heated, and the yarn breaks just below the surface of the die.

The heating hood 2 is provided immediately below the spinneret 1 and preferably has a length of 100 to 250 mm. If the length of the heating hood is less than 100 mm, the temperature may fluctuate due to the influence of the hot air blown from the hot air blowing device 3 below the heating hood 2 on the base surface. On the other hand, if it exceeds 250 mm, since the yarn is in a non-solidified state, fusion between the single yarns tends to occur during running.

Next, the yarn Y passing through the heating hood 2 is heated by a hot air blowing device 3 provided immediately below the heating hood 2.
Then, hot air in a specific range of temperature, which is determined by the single-filament fineness, the number of filaments, the draft value, the bundle position of the yarn, and the relative viscosity of the used chip, is blown. Note that the draft value refers to a magnification of the take-up speed to the discharge linear speed.

By blowing such warm air at a stage where the yarn has not yet completely solidified, the solidification point of the yarn can be moved downward and the tension acting on the yarn can be reduced. is there. Thereby, the position where the accompanying airflow generated due to the solidification of the yarn can be lowered, the running of the yarn can be stabilized, and the occurrence of yarn spots and the cutting of a single yarn can be reduced.

In particular, since the tension acting on the yarn can be reduced, the effect is high in the case of manufacturing a brand having a spinning condition that provides a high draft value.

Further, when hot air is blown, the temperature of the blown air does not gradually rise from the blowout side due to the heat from the spun yarn, so that the blown yarn is separated from the blown yarn and the blowout side. The difference in tension between the yarn at the position and the yarn does not increase, and it is possible to manufacture a yarn having a uniform yarn quality. Further, it is possible to suppress the cutting of the yarn due to the over tension resulting from the difference in tension between the yarns, and it is possible to improve the operability.

In general, the finer the fineness of a single yarn, the higher the temperature of the hot air to be blown. This is because the tension acting on the yarn generally increases as the single yarn becomes thinner. The higher the draft value, the higher the temperature of the hot air to be blown. This is because the higher the draft value, the higher the tension acting on the yarn. Furthermore, it is necessary to increase the temperature of the hot air to be blown as the number of filaments increases. This is to prevent the temperature of the hot air from rising from the spraying side, to make the temperature of the hot air uniform, and to reduce the difference in tension acting on the yarn between the upwind and the downwind.

The higher the relative viscosity of the chips used, the higher the temperature of the hot air to be blown. This is because the higher the relative viscosity, the higher the tension acting on the yarn. Furthermore, the warm air temperature can be increased as the distance to the yarn converging point is increased, and thereby a higher effect can be obtained.

As a result of considering the above, it is assumed that the temperature of the hot air blown from the hot air blowing device satisfies any of the following (1) to (3). First, the condition (1) is for producing a general clothing yarn having a polymer relative viscosity of 3.00 or less, and 2.5 × A ≦ hot air temperature (° C.)
≦ 6.0 × A. The condition (2) is a condition in which the relative viscosity of the polymer is greater than 3.00 and the distance between the convergence point of the yarn after cooling and solidification and the lower surface of the spinneret is within 200 cm. (Relative viscosity / 2.50) ² × A ≦
Hot air temperature (° C) ≦ 6.0 × (relative viscosity / 2.50) ² × A
And The condition (3) is that the relative viscosity of the polymer is 3.0.
0, and the distance between the convergence point of the yarn after cooling and solidification and the lower surface of the spinneret exceeds 200 cm,
2.5 × (relative viscosity / 2.50) ² × (1 / 0.75) ×
A ≦ hot air temperature (° C.) ≦ 6.0 × (relative viscosity / 2.50) ²
× (1 / 0.75).

In each case, if the temperature of the hot air is lower than the specified range, the effect of blowing the hot air as described above becomes insufficient, and it is possible to obtain a fiber having no spots and excellent uniformity. become unable. On the other hand, if the temperature of the hot air is higher than the specified range, the temperature becomes too high, causing problems such as fusion between the single yarns or yarn breakage, and the operability is reduced.

It is preferable that the length of the blowing section for blowing hot air from the hot air blowing device is 100 to 300 mm. When the length of the blowing portion is less than 100 mm, the effect of blowing the warm air as described above is reduced. On the other hand, if it exceeds 300 mm, the solidification point is lower, so that fusion between the single yarns occurs or cooling in the next cooling zone tends to be insufficient.

After blowing hot air with a hot air blowing device,
Cooling and solidification are performed by blowing cooling air of 20 ° C. or less. When the temperature of the cooling air exceeds 20 ° C., the solidification by cooling becomes insufficient, and when an oil agent is applied in a subsequent step to the yarn that has not been completely solidified, the yarn has poor physical properties such as strength and elongation. Article.

After the yarn is cooled and solidified in this way, an oil agent is applied, and the yarn is taken up by a take-up roller. Thereafter, the yarn may be wound up as it is without stretching, or may be stretched between rollers. You may wind up after you go.

[0024]

The present invention will be described below in more detail with reference to examples. The measurement and evaluation of the physical properties of the yarns in the examples were performed as follows. (1) Evaluation of C% Using Evenest Tester 80 Type C manufactured by Keisoku Kogyo Co., Ltd., selector 1/2 inert, yarn speed 200 m / min, running time 2
The yarn was run under the condition of minutes, the maximum value and the minimum value were read, and the value obtained by dividing the sum of the maximum value and the minimum value by 2 was defined as C%. (2) Strength / cutting elongation Using an autograph manufactured by Shimadzu Corporation, down speed 25
cm / min, strength (g) and elongation at break were measured under the condition of a sample length of 25 cm, and the value obtained by dividing the obtained strength by the denier number was the strength (g / d).
Both the strength and the elongation at break were taken as the average values of 25 measurements. (3) Variation in Yarn Diameter The single yarn diameter of all the single yarns constituting the filament was read from a micrograph, and the standard deviation value was used. (4) Yarn breakage rate The number of occurrences of yarn breakage under the nozzle per 100 weights for 24 hours. (5) Operability 5 kg winding was regarded as full winding, and the ratio of the actually obtained full winding number to the full winding number obtained in 5 days assumed from the winding time was defined as the ratio.

Example 1 Using an apparatus shown in FIG. 1, nylon 6 having a relative viscosity of 2.50 was used.
The chips were melted at a melting temperature of 262 ° C., spun from a spinneret (68 holes), and a yarn was spun into a heating hood (length: 180 mm) at an ambient temperature of 210 ° C. Then, a hot air spraying device (length of spraying part: 150 mm) is applied to this yarn.
Blow 90 ° C hot air, then 20 ° C cooling air,
Cooled and solidified. Then, an oil agent was applied, and 3780 m /
The yarn was taken up by a take-up roller for 0.5 minute, stretched by 0.5% between the rollers, and wound up to obtain a yarn of 40 denier / 68 filament. The draft value at this time was 465.

Examples 2 and 3 and Comparative Examples 1 and 2 Tables 1 and 2 show the temperatures of the hot air blown from the hot air blowing device.
The procedure was performed in the same manner as in Example 1 except for the change as shown in (1).

Example 4 Using the apparatus shown in FIG. 1, nylon 6 having a relative viscosity of 3.50 was used.
The chips were melted at a melting temperature of 278 ° C., spun from a spinneret (24 holes), and the yarn was spun into a heating hood (180 mm long) at an ambient temperature of 230 ° C. Then, a hot air spraying device (length of spraying part: 150 mm) is applied to this yarn.
Hot air of 100 ° C. was blown, and then cooling air of 20 ° C. was blown to cool and solidify. Thereafter, an oil agent was applied and 2830
The yarn was taken up with a take-up roller of m / min, stretched 1.5 times between the rollers, and then wound up to obtain a 30 denier / 24 filament yarn. The convergence point at this time was 430 cm from the lower surface of the spinneret, and the draft value was 150.

Examples 5 to 6 and Comparative Examples 3 to 4 Tables 1 and 2 show the temperatures of the hot air blown from the hot air blowing device.
Example 4 was carried out in the same manner as in Example 4, except that the conditions were changed as shown in (1).

Example 7 Using an apparatus shown in FIG. 2, nylon 6 having a relative viscosity of 3.50 was used.
The chips were melted at a melting temperature of 278 ° C., spun from a spinneret (280 holes), and the yarn was spun into a heating hood (200 mm length) at an ambient temperature of 300 ° C. Then, a hot air spraying device (length of spraying part: 150 mm) is applied to this yarn.
Blow 95 ° C hot air, then blow 15 ° C cooling air,
Cooled and solidified. Thereafter, an oil agent was applied, the product was taken up by a take-up roller of 500 m / min, stretched 5.4 times between the rollers, and then wound up to obtain a 1680 denier / 280 filament yarn. The convergence point at this time is 200 mm away from the lower surface of the spinneret.
cm and a draft value of 30.

Examples 8 and 9 and Comparative Examples 5 and 6 Tables 1 and 2 show the temperatures of the hot air blown from the hot air blowing device.
Example 7 was carried out in the same manner as in Example 7, except for the following changes.

Table 1 shows the evaluation results of C%, strength / cut elongation, variation in single yarn diameter, yarn breakage rate, and operability of the fiber yarns obtained in Examples 1 to 9 and Comparative Examples 1 to 6. It is shown in FIG.

[0032]

[Table 1]

[0033]

[Table 2]

As is clear from Tables 1 and 2, Examples 1 to 9
The polyamide fiber yarn obtained in the above was excellent in evaluation of C% and variation in single yarn diameter, that is, excellent in uniformity, small in yarn breakage, and good in operability. On the other hand, Comparative Example 1,
In 3 and 5, since the warm air temperature was too low, the solidification point of the yarn was moved downward, the tension acting on the yarn could not be reduced, and the running of the yarn could not be stabilized.
The operability was poor, and a fiber yarn excellent in uniformity could not be obtained. In Comparative Examples 2, 4, and 6, since the hot air temperature was too high, fusion between the single yarns occurred, resulting in very poor operability.

[0035]

According to the melt spinning method of the present invention, the yarn can be stably spun without fluctuating the temperature of the spinneret surface, and the spinneret is discharged by appropriately lowering the solidification point. In addition to reducing the tension of the yarn, the tension between the single yarns can be made uniform, and the occurrence of draft cutting or the like can be prevented, so that a fiber yarn with good operability and excellent uniformity can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of a melt spinning method of the present invention.

FIG. 2 is a schematic explanatory view showing another embodiment of the melt spinning method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spinneret 2 Heating hood 3 Hot air blowing device 4 Cooling air blowing device 5 Slit nozzle 6 Take-up roller 7 Exhaust duct 8 Cold air duct 9 Heater 10 Oiling roller 11 Outlet

Claims (2)

[Claims] An atmosphere temperature in a heating hood immediately below a spinneret is (polymer melting temperature minus 70 ° C.) to (polymer melting temperature plus 50 ° C.), and a hot air blowing device is provided immediately below the heating hood. The hot air blowing device blows warm air having a temperature that satisfies any of the following (1) to (3) onto the melt spun yarn that has passed through the inside,
A method for melt-spinning polyamide fiber yarns, which comprises cooling and solidifying the yarns by blowing cooling air at a temperature of not more than ° C. (1) When the relative viscosity of the polymer is 3.00 or less 2.5 × A ≦ Hot air temperature (° C.) ≦ 6.0 × A (2) The relative viscosity of the polymer is greater than 3.00 and after cooling and solidification When the distance between the yarn converging point and the lower surface of the spinneret is 2
When it is within 00 cm 2.5 x (relative viscosity / 2.50) ² x A ≤ hot air temperature (° C)
≦ 6.0 × (relative viscosity / 2.50) ² × A (3) The relative viscosity of the polymer is greater than 3.00, and the distance between the converging point of the yarn after cooling and solidification and the lower surface of the spinneret is 2
When it exceeds 00 cm 2.5 × (relative viscosity / 2.50) ² × (1 / 0.75) ×
A ≦ hot air temperature (° C.) ≦ 6.0 × (relative viscosity / 2.50) ²
× (1 / 0.75) The relative viscosity was determined by using 96% by weight sulfuric acid as a solvent and a concentration of 1%.
g / dl, measured at a temperature of 25 ° C., and A = (square root of filament number × common logarithm of draft value) / square root of single yarn fineness (d). 2. The length of the heating hood is 100 to 250 m.
m, the length of the blowing section of the hot air blowing device is 100 to 30
The method for melt-spinning a polyamide fiber yarn according to claim 1, which is 0 mm.