JPH0578911A - Melt-spinning of ultra-fine polyester multifilament - Google Patents

Abstract

PURPOSE:To easily and stably perform the high-speed melt-spinning of a specific ultra-fine polyester multifilament in high operability without using a particular apparatus by applying a lubricant under specific condition. CONSTITUTION:An ultra-fine polyester multifilament yarn composed of 100-200 filaments and having a single fiber fineness of <=0.7d after spinning is formed by melt-spinning, coated with a lubricant and taken up at a take-up speed of 2,500-4,000m/min. In the above process, roller-type oiling apparatuses are arranged in two stages between a spinneret 1 and a take-up roller 7 and a lubricant is applied in a state satisfying the formulas C1=2 to 8, T1=5 to 29, C2=10 to 16 and T2=20 to 40 wherein C1 (wt.%) is the concentration of the lubricant film at the 1st-stage roller-type oiling apparatus 4 near the spinneret 1, T1 (mum) is the thickness of the lubricant formed on the oiling roller, C2 is the concentration of the lubricant at the 2nd-stage roller-type oiling apparatus 6 and T2 is the thickness of the lubricant film on the 2nd-stage roller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melt-spinning method for producing a polyester ultrafine fiber having a single-filament fineness of 0.7d (converted to a fineness after drawing of 0.3 to 0.6d) or less after spinning take-up, and particularly to polyester. The present invention relates to a melt-spinning method for polyester ultra-fine multi-filaments, which produces ultra-fine fibers continuously at high speed and stably without using a special device.

[0002]

2. Description of the Related Art So-called ultrafine fibers having a single yarn fineness of 1 d or less have an excellent texture and are widely used for obtaining natural leather-like fabrics and peach-skin fabrics.

As a method for producing an ultrafine fiber having a single yarn fineness of 1 d or less, (1) a method of dissolving and removing sea components of a sea-island type composite fiber (Japanese Patent Publication No. 48-25362), (2) a bonded type composite Method for splitting fibers (Japanese Patent Laid-Open No. 51-130317)
(3) Ordinary spinning, a method of thinning a yarn by a drawing process to obtain ultrafine fibers (JP-A-55-26201), (4) Spinning at a high speed of 2500 m / min or more. , A method of obtaining oriented ultrafine fibers (JP-A-54-30924), and the like have been proposed.

Among these methods, the methods (1) and (2) require a special spinning device, and must use two or more kinds of polymers to perform operations such as melting and splitting. Therefore, it is very expensive, and furthermore, it is difficult to manufacture industrially uniform ultrafine fibers.

In the method (3), as the single yarn fineness becomes smaller, the number of yarn breaks during drawing increases, it is difficult to obtain ultrafine fibers of 0.7d or less, and fineness unevenness also becomes large.

On the other hand, according to the high-speed spinning method (4), the discharge amount per spinning hole perforated in the spinneret increases, the spinning tension is applied, and the yarn swinging is alleviated. Due to the effects of high orientation, the fineness unevenness is reduced, and there is an advantage that ultrafine fibers can be obtained relatively easily without any trouble.

Conventionally, in order to obtain ultrafine fibers by ordinary high-speed spinning, a method of arranging the ejection holes formed in the spinneret is devised, and the air resistance received by the yarn after cooling is suppressed as much as possible during spinning. It is necessary to make sure that the tension does not become too high, or to control the yarn cooling rate.
This method made it possible to produce ultrafine fibers with a single-filament fineness of 0.5d after spinning (single-filament fineness after drawing of 0.3-0.4d).

However, in the case of producing ultrafine fibers by the above method, when compared with the operability of general yarns of 2 to 3d,
The yarn breakage rate in spinning is high, single yarn breaks and loops (slack yarns) are mixed in the wound package, and troubles in the post process frequently occur due to this, which is unsolved industrially. There are many problems.

Further, in Japanese Patent Laid-Open No. 56-107006, 2500
A method of arranging oiling rollers in two stages has been proposed for producing ultrafine multifilaments having a fineness of 0.7d or less by melt spinning at a high speed of m / min or more. However, in this method, the concentration of the oil agent and the film thickness of the oil agent on the oiling roller are not taken into consideration, and the amount of oil agent required for yarn focusing and the amount of oil agent required for post-processing are applied to the yarn. There was a problem that it could not be properly attached.

[0010]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and is an ultrafine multifilament having a single-filament fineness after spinning take-up of 0.7d (single-filament fineness after drawing is 0.3 to 0.6d). It is a technical object to provide a melt-spinning method for polyester ultra-thin multifilaments, which can be easily and stably produced by high-speed spinning.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention can solve the above-mentioned problems by selecting the conditions for applying a spinning oil agent within a specific range. And found the present invention.

That is, according to the present invention, a polyester fine multifilament having a single yarn fineness of 0.7d or less and a filament number of 100 to 200 after spin take-up is melt-spun, an oil agent is applied thereto, and then a take-up speed of 2500 to In the method of drawing at 4000 m / min, the roller type oiling device is arranged in two steps between the die surface and the take-up roller, and the oil concentration C ₁ (weight %)When,
Oil film thickness T ₁ (μ
m) and the oil concentration C ₂ (wt%) in the second stage roller type oiling device close to the take-up roller and the oil film thickness T ₂ (μm) formed on this oiling roller satisfy the following equations respectively. The gist is a method for melt spinning a polyester ultra-fine multifilament, which is characterized in that an oil agent is applied as described above. 2 ≦ C ₁ ≦ 8 ………… 5 ≦ T ₁ ≦ 20 …… 10 ≦ C ₂ ≦ 16 …… 20 ≦ T ₂ ≦ 40 ……

The present invention will be described in detail below. The polyester in the present invention is mainly a polyester having an ethylene terephthalate unit as a main repeating unit. As long as the properties of the polyester are not essentially changed, a third component such as isophthalic acid or 5-sodium sulfoisophthalate is used. A copolyester obtained by copolymerizing a dicarboxylic acid such as an acid and diols such as propylene glycol, 1,4-butanediol, diethylene glycol and polyethylene glycol may be used. Further, polyester may be added with a matting agent, a stabilizer, a coloring agent, a flame retardant, a surface improving agent and the like.

The degree of polymerization of polyester may be appropriately selected according to the type of polyester and the intended use of the yarn. Generally, in the case of polyethylene terephthalate, one having an intrinsic viscosity [η] of 0.55 to 0.75 is suitable. Is.

The filament may be composed of a single component polyester or a plurality of component polyesters. In the case of a plurality of components, a composite fiber such as side-by-side or core-sheath may be used. The cross-sectional shape of the filament is not limited to a round cross-section, but may be a modified cross-section such as a triangle or a flat shape.
It may be a hollow fiber.

Further, the spinning speed is required to be 2500 to 4000 m / min. At a low speed of less than 2500 m / min, it is necessary to increase the draw ratio and the drawability is lowered, and the discharge rate is reduced. It is not preferable because it becomes smaller and the fineness unevenness increases. On the other hand, when the speed is higher than 4000 m / min, the increase in spinning tension due to the increase in air resistance causes the spinnability to be extremely deteriorated and the yarn breakage rate to increase, which is not preferable.

The number of filaments is set based on the discharge amount per spinneret, the size of the single yarn fineness to be obtained, etc., but using a general spinneret with a spinneret surface diameter of 50 mm to 100 mm, In order to obtain an undrawn yarn having a single yarn fineness of 0.7 d or less, the number of holes is suitably 100 to 200. If it is less than 100, the discharge amount per spinneret becomes too small, which is not economically preferable. If the number of holes exceeds 200, unevenness in fineness increases due to poor cooling of the yarn, and spun yarn breakage also extremely increases, which is not preferable.

Generally, as a method for applying an oil agent, (A) an oil agent is supplied to an oil bath, and a roller immersed in this is rotated,
A roller oiling method in which an oil film is formed on the roller, and the yarn is brought into contact with the roller to apply the oil film, (B) The oil agent is measured with a metering gear pump, and the thread touch part of the yarn guide made of ceramic or the like is finely applied. There are a guide oiling method in which holes are provided and the oil agent is discharged and applied from this, and (C) an atomizer type oiling method in which the oil agent is mixed into compressed air and sprayed onto the running yarn. In the present invention, it is necessary to adopt the roller lubrication method (A), which applies an oil agent before focusing the yarns, and has a so-called wide yarn width (the filaments are close to the parallel state). It can be applied in the state, so that it can be applied uniformly to the multifilament.

However, while the roller lubrication method has the advantage that the oil agent can be uniformly applied to the multifilament, as the single yarn fineness decreases, the resistance of the oil film formed on the roller cannot be ignored, and above all When the fineness of a single yarn is 0.7d or less like the ultra-fine multifilament targeted by the present invention, the fiber diameter becomes extremely smaller than the oil film thickness formed on the roller, resulting in a so-called fluid friction state and a large running You will receive resistance. Therefore, it is necessary to reduce or reduce the running resistance by changing the fluid friction state to the boundary friction state by reducing the film thickness.

At this time, however, it is necessary to pay attention to the quality of yarn converging. If the amount of oil agent adhered is small, the yarn gathering property will be impaired, and static electricity will be generated due to friction with the yarn guide while running, and the yarn will be charged and the yarn bundle will be in a split state, significantly impairing operability. become. For this reason, it becomes necessary to maintain an appropriate oil film thickness and yet to secure the amount of oil adhesion.

As a method of controlling the oil agent film thickness, (a) a physical control method based on the rotation speed of the oiling roller, (b) a method based on the oil agent concentration (viscosity), (c) a method based on the oil agent component (composition), D) There are methods such as the method of changing the viscosity depending on the oil temperature.However, the method of (c) is not preferable because there is a balance with the performance required from the intended use of the ultrafine filament, and the method of (d) is also oily. Equipment for controlling temperature is required, and neither is practical.
The method of controlling by combining with (b) is a preferable method in terms of accuracy and control.

According to a study by the present inventors, the single yarn fineness is 0.
A polyester ultrafine multifilament having a filament number of 100 to 200 with a diameter of 7d or less was melt-spun and a take-up speed of 2500
In order to reduce the spinning tension as much as possible and to obtain the amount of oil agent adhesion necessary for yarn focusing in order to prevent deterioration of spinnability and yarn breakage when taking up at ~ 4000 m / min, the oil agent in the first stage oiling device is used. The concentration is set within the range of 2 to 8%, preferably 2 to 6%, and the rotation speed of the first-stage oiling roller is controlled to control the oil film thickness formed on the roller to 5 to 20 μm.
It has been found that setting m is the most suitable condition.

If the concentration of the oil agent is less than 2%, the solution viscosity is too low, the surface tension is low, and the oil film to be formed on the roller becomes uneven, which is not preferable. On the other hand, if it exceeds 8%, on the contrary, the surface tension is too high, and as a result, it is necessary to extremely reduce the number of rotations of the roller, which causes inconveniences such as an increase in the load on the roller drive motor and occurrence of uneven rotation. Not preferable.

When the film thickness of the oil agent is less than 5 μm, the amount of the oil agent is practically insufficient and the focusing property is impaired, and when it exceeds 20 μm, the fluid friction state occurs and the resistance is received when the yarn passes, so that the yarn is damaged. Single yarn breakage may occur, or loops may occur due to unevenness of focusing (alignment unevenness) between single yarns.

As described above, in order to spin an ultrafine multifilament of 0.7d or less with good operation, it depends largely on the oiling agent application method. The amount of oil required for processing cannot be satisfied. To solve this, a second stage oiling device is required.

The concentration of the oil agent used in the second-stage oiling device is required to be 10 to 16%, preferably 10 to 14%. When the oil concentration is less than 10%, the surface tension is low and the film thickness is 20
Control over μm becomes unstable. Oil concentration is 16
%, The film thickness increases with a rapid increase in viscosity,
It is not preferable because it may cause breakage of a single yarn or a loop.

Similarly, the film thickness is 20 to 40 μm, preferably 20.
It is necessary to adjust the number of revolutions of the roller to 30 .mu.m, and it is preferable to supply 0.3 to 1.5% by weight of the oil agent required for post-processing. If the film thickness exceeds 40 μm, the amount of oil agent adhered becomes excessive, and if the film thickness is less than 20 μm, the amount of oil agent adhered necessary for the subsequent process becomes insufficient or is not stable.

Regarding the position of the oiling device, the first stage of the oiling device is preferably 600 to 1000 mm downstream from the spinneret surface in terms of yarn cooling and spinning tension, and the second stage of the oiling device is of the first stage. A position of 3000 to 5000 mm away from the device is preferred. The reason is that it takes time for the oil agent applied by the first-stage oiling device to sufficiently permeate (migrate) between the filaments.

Under the oil agent application conditions set as described above, the polyester ultra-fine multifilament spun from the spinneret has an increase in spinning tension due to an extreme oil film resistance in the first stage oiling, and the alignment caused by the increase. After there are no spots and the amount of oil required for yarn focusing is applied, 2
The oiling in the second stage adjusts the total amount of oil required in the post-processing process and winds the package.

The oil agent used in the present invention is a commonly used spinning oil agent, which contains a copolymer of propylene oxide and ethylene oxide as a main component, and a fatty acid ester, a nonionic surfactant, an antistatic agent, etc. It is preferable to use a spinning oil containing the above components or a spinning oil containing a mineral oil and a fatty acid ester as the main components and a nonionic surfactant, an antistatic agent, or the like.

Next, the present invention will be described with reference to the drawings. Figure 1
FIG. 3 is a schematic process drawing showing one embodiment of the method for melt spinning a polyester ultrafine multifilament of the present invention. The yarn 2 discharged from the spinneret 1 is cooled by cold air from the cooling device 3, oiled by the first stage roller type oiling device 4, and then bundled by the yarn entanglement treatment device 5. The bundled yarn is re-lubricated by the roller type oiling device 6 in the second stage ^, and wound up as a package 8 by the winding device via the take-up rollers 7 ^, 7.

[0032]

EXAMPLES Next, the present invention will be specifically described by way of examples. In addition, the oil film thickness in the examples is obtained by pressing the absorbent cotton against the entire width of the yarn contact surface of the rotating oiling roller, wiping off the oil film formed on the roller, weighing it, and using the following formula. Is calculated as Oil agent film thickness T = W × 10 ⁴ / (ρ × π × R × L × r) W = weight of oil agent wiped (g) ρ = density of oil agent (g / cm ³ ) π = circular ratio R = Diameter of oiling roller (cm) L = Width of oiling roller (cm) r = Rotation speed after wiping the oiling roller (times)

Example 1 Polyethylene terephthalate having an intrinsic viscosity [η] of 0.68 measured at 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent and 0.40% by weight of titanium oxide as a matting agent was used. According to the process of Fig. 1, using a spinneret having 168 spinning holes with a diameter of 0.15 mm, discharge was performed at a discharge rate of 25.6 g / min, and was drawn at a spinning speed of 3200 m / min.
I wound up the yarn.

In the experiment a, the oil concentration was 4% in the first stage oiling, and the roller rotation speed was set so that the film thickness was 10 μm. In addition, the oil concentration in the second step was 14
%, And the film thickness was set to 30 μm.

In Experiments b to d, the oil concentration and the film thickness of the oiling of the first and second stages were changed as shown in Table 1, and the other conditions were the same as those of Experiment a.

Experiments e to h were carried out by changing the spinning speed and the number of filaments.

The packages wound under the conditions of experiments a to h in Table 1 were free from single yarn breaks, loops, fluffs, etc.
There was no yarn breakage during spinning, and production was extremely stable.

Comparative Example 1 Spinning and winding were carried out in the same manner as in Example 1 except that the roller type oiling device was used only in the first stage and various conditions for applying an oil agent were changed as shown in Table 1.

Comparative Example 2 Spinning and winding were carried out in the same manner as in Example 1 except that various conditions for applying an oil agent were changed as shown in Table 1.

In the case where the roller type oiling device of Comparative Example 1 has a single stage, as in Experiment k, the required amount of oil could not be finally secured even though the operability was good. In addition, experiments i, j
Finally, in order to secure the required amount of oil agent, the oil agent concentration was increased, but in this case, it was not possible to obtain extra fine yarn without defects.

In Experiment 1 of Comparative Example 2, the film thickness was 20 μm even when the oil concentration of the first stage roller type oiling device was 4%.
Since it exceeded the limit, the adherence of single thread breakage was noticeable on the guides under the roller type oiling device, and there were many fluffs and single thread breakages on the package. In Experiment m, the film thickness on the first-stage oiling roller was set to 4 μm, but
Due to the generation of static electricity, the yarns were not bundled together and the single yarns were separated. In addition, the phenomenon that the oil agent is scattered on the second-stage oiling roller occurs, the amount of yarn waste attached to the guide also becomes large, and many yarn breakages occur.

[0042]

[Table 1]

The operability criteria shown in Table 1 are:
The number of broken yarns per day for 12 spindles and the defect rate of the package calculated by the following formula were used for ranking. Package defect rate (%) = number of defective packages / total number of packages x 100 Rank of yarn breakage Package defect rate ◎: 1 or less 1 or less ○: 1-2 2 1-2 △: 3-5 3-5 ×: 6 6 or more

[0044]

As described above, according to the melt-spinning method for polyester ultra-fine multifilaments of the present invention, the single-filament fineness after take-up is 0.7d or less and the number of filaments is 10d.
It is possible to dramatically improve the operability when melt-spun 0 to 200 polyester ultra-fine multifilaments and take it off at a take-up speed of 2500 to 4000 m / min. It is possible to provide a manufacturing method.

[Brief description of drawings]

FIG. 1 is a schematic process drawing showing an embodiment of the present invention.

[Explanation of symbols]

1 Spinneret 2 Thread 3 Cooling device 4 Roller type oiling device of 1st stage 5 Thread entanglement processing device 6 Roller type oiling device of 2nd stage 7 ^, 7 ^{, Take-up} roller 8 Package

Claims (1)

[Claims] 1. A superfine multifilament of polyester having a single yarn fineness of 0.7d or less and a filament number of 100 to 200 after the take-up is melt-spun, an oil agent is applied, and then a take-up speed is 2500 to 4000 m / min. In the method of pulling with a roller, a roller type oiling device is installed between the die surface and the pulling roller.
The oil concentration C ₁ (% by weight) in the roller type oiling device of the first stage, which is arranged in a row and is close to the die surface, the oil film thickness T ₁ (μm) formed on this oiling roller, and the take-up roller. The oil agent is applied so that the oil agent concentration C ₂ (% by weight) in the _second roller type oiling device and the oil agent film thickness T ₂ (μm) formed on this oiling roller satisfy the following expressions, respectively. A method for melt spinning a polyester ultra-fine multifilament, which comprises: 2 ≦ C ₁ ≦ 8 ………… 5 ≦ T ₁ ≦ 20 …… 10 ≦ C ₂ ≦ 16 …… 20 ≦ T ₂ ≦ 40 ……