JPS6140763B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a spinning method in melt spinning synthetic fibers, in which a measured amount of oil is applied to the cooled yarn after being discharged from a spinneret, and the yarn is then taken up. In recent years, with the advancement of ultra-fine fibers and POY-DTY technology, the filament fineness is around 1 denier in pursuit of new textures and high-class appearance of woven and knitted fabrics.
Fibers spun at high speeds of 2500 m/min to 4000 m/min have come to be required. However, to produce these fibers, the filament denier must be 2 to 5 deniers and the spinning speed must be 1000 to 1500.
In conventional melt spinning at speeds of about m/min, increases in spinning tension due to air resistance acting on the yarn during spinning and variations in the amount of oil deposited have become major problems. In order to solve these problems, a method (hereinafter referred to as the metered lubrication method) has been proposed in which a metered amount of oil is continuously applied to the yarn being spun using a metering pump instead of the conventional lubrication method using oiling rolls. . In this method, a lubricant applicator is installed at a position closer to the spinneret than a conventional oiling roll, and a measured amount of lubricant is applied to the spun yarn while converging it. This prevents the spinning tension from increasing after lubricating, and prevents the lubricant from increasing. The aim is to reduce adhesion spots. When actually implementing this metered lubrication method,
Traditional spinning machines are often modified. Here, a conventional spinning machine will be explained using figures. FIG. 1 is a front view showing an oiling roll type spinning machine, and FIG. 2 is a front view showing a metered oiling type spinning machine. In an oiling roll type spinning machine, as shown in FIG. 1, spinning parts such as a spinning head 1, a spinneret 11, a cooling device 2 for cooling the spun yarn 13, etc. are usually located upstairs, and a cooling cylindrical duct 3 is installed. Oiling roll 4, first, second through
It has a structure in which winding parts such as godet rolls 5 and 6 and a winding device 14 are provided on the floor 9 below. When converting such an oiling roll type spinning machine to a metered lubrication type, the installation position of the metered lubrication device needs to be closer to the spinneret than the oiling position in the oiling roll type, in order to prevent the spinning tension from increasing due to the air resistance mentioned above. However, considering the workability of threading during spinning, it is recommended to install an oil applying device 7 between the cooling device 2 on the floor and the floor 10 as shown in FIG. 1972-
It is convenient to provide a lubricant applicator at the lower end of the cooling chamber or inside the cooling chamber, as shown in Japanese Patent No. 70111. However, regarding this method of metering and refueling at a position closer to the mouthpiece than the oiling roll method,
As a result of our investigation, we found the following drawbacks. For example, when performing metered lubrication on the floor as shown in FIG.
Even if 100% of the measured lubricant is applied to the yarn while converging the spun yarn using a spindle, the distance between the yarn presser guide 8 and the first godet roll 5 will vary depending on the height of each floor of the building. Since the length is usually about 2 to 5 m, the filament separates from the focused yarn due to air resistance and string vibration of the yarn and runs during this time, resulting in abnormal tension being applied to the separated filament, or filament breakage. There are problems in that it causes threads to stick to the godet roll, fuzz and sag on the winding drum. In order to solve these problems, the present inventors
As a result of various studies, we have arrived at the present invention. That is, in the present invention, the distance between the yarn presser guide provided below the oil agent applicator for applying a measured amount of oil onto the spun yarn and the first godet roll is
When performing melt spinning using a spinning machine with a length exceeding 1.0 m, a yarn convergence guide is provided between the yarn presser guide and the first godet roll, and the yarn tension (T ₁ ) at the exit of the yarn presser guide is This melt spinning method is characterized in that the difference (T) between the yarn tension (T ₂ ) and the yarn tension (T 2 ) at the entrance of the yarn focusing guide satisfies equation (1). T≦0.2To＋0.8Tc ……………(1) However, T=T ₂ −T ₁ To is the theoretical value of the tension generated by air resistance between the yarn presser guide and the yarn convergence guide for completely unfocused yarn. and is calculated using equation (2). To= ^{0.37・Red -0.61 ・}(ρa/2)・π・V ²・D・n・L/980(g) ……………(2) Red: Reynolds number of filament Red=D・V・ρa・μa ^-1 D: Diameter of filament (cm) (In the case of yarn with irregular cross section, it is the equivalent diameter when converted to a round cross section) V: Spinning speed (cm/sec) n: Filament constituting the yarn (n is 2 or more) ρa: Standard air (temperature 20℃, absolute pressure 760mmHg,
(relative humidity 75%) density: 1.20×10 ^-3 g・cm ⁻³ μa: Standard air viscosity: 1.82×10 ⁻⁴ g・cm ⁻¹・sec ⁻¹ Distance (cm) Tc is the theoretical value of the tension generated by air resistance between the thread presser guide and the thread focusing guide of a completely focused thread, and is calculated by equation (3). Tc=0.37・Redc ^-0.61・(ρa/2)・π・V ²・Dc・^L /980(g) ……………(3) Redc: Reynolds number of perfectly focused yarn Redc=Dc・V・ρa・μa ^-1 Dc: Diameter of the circumscribed circle of a completely focused yarn (cm) Here, T is the yarn tension T ₁ at the exit of the yarn presser guide and the yarn tension T at the entrance of the yarn convergence guide, as described above. ₂
, that is, the increase in tension due to air resistance that the traveling yarn receives from the yarn presser guide to the yarn convergence guide. Therefore, when the yarn is well bundled, T
The value of becomes small, and conversely becomes large when the focusing state is poor. As mentioned above, To is the theoretical value of the tension generated by air resistance in the yarn presser guide and yarn convergence guide when each filament that makes up the yarn runs completely separated from each other. be. On the other hand, Tc is the theoretical value of the tension generated by air resistance between the yarn presser guide and the yarn convergence guide when each filament constituting the yarn travels in a completely converged state. , is an air resistance value calculated assuming that one filament has a diameter equivalent to the circumscribed circle of the yarn. Therefore, in the case of normal spinning, T is smaller than To and larger than Tc. The present invention is achieved when spinning under conditions where T satisfies formula (1); The convergence of the yarn is poor, resulting in yarn breakage, fluff, sagging on the winding drum, etc., resulting in poor spinnability. Next, the present invention will be explained using figures. FIG. 3 is a front view of a spinning machine showing a preferred embodiment of the present invention. The present invention is effective when the distance Lo between the thread presser guide 8 and the first godet roll 5 exceeds 1 m. When Lo is 1 m or less, the above-mentioned problem does not occur even if the method of the present invention is not particularly used, as long as the spun yarn is bundled using the lubricant applicator 7 and the yarn presser guide 8. But Lo is 1
If the yarn exceeds m, even if the yarn is focused using the lubricant applicator 7 and the yarn presser guide 8, the filament will separate during the run until it reaches the first godet roll 5 as described above, which will cause a problem, so this problem has been solved. In order to do this, a yarn convergence guide 12 that can adjust the degree of convergence of the yarn is provided between the yarn presser guide 8 and the first godet roll 5.
It is necessary to adjust the bundled state of the threads. The mounting position of the yarn convergence guide 12 is preferably set so that the distance between the first godet roll 5 and the yarn convergence guide 12 is less than 1 m. The method of adjusting the degree of convergence in the yarn convergence guide is not particularly limited as long as the above-mentioned formula (1) can be satisfied. The yarn convergence guide 12 used in the present invention is not particularly limited as long as it satisfies the above-mentioned conditions.
Or, it is a combination of three guide pieces, and at least one guide piece is different from the other so that the contact state between the thread and the guide piece can be changed, for example, by changing θ in Fig. 4, the convergence state can be changed. Preferably, the arrangement is such that the position of the guide piece relative to the guide piece can be changed. In Figures 4, 5, and 6, A is a front view, B is a side view, and 13 is a spun yarn. Note that at least one of the yarn converging guides 12 composed of two or three guide pieces has a structure with a recess so that the traveling position of the yarn can be reliably regulated. preferable. In addition, the material of each guide piece of the yarn convergence guide 12 can be low-purity alumina ceramic with an alumina content of 85 to 95%, high-purity alumina ceramic with an alumina content of 99% or more, titanium porcelain, etc. However, high-purity alumina ceramic is particularly preferred, and the surface viscosity of the guide piece is preferably 3S or less. The specific method for adjusting the yarn convergence guide is to actually measure the yarn tension T ₁ directly below the thread presser guide and the yarn tension T ₂ at the entrance of the yarn convergence guide, and adjust the tension so that the difference T satisfies equation (1). This can be done by adjusting the yarn focusing guide, for example, by changing θ in FIG. As described above, by adopting the present invention, the degree of convergence of the spun yarn is improved, there is no filament breakage, no winding on the godet roll, no sagging on the winding drum, and continuous spinning for a long time is possible. Ta. The present invention is effective for melt spinning thermoplastic synthetic fibers such as nylon 6, nylon 6.6, polyester, etc., but especially at least 85 mol% of the constituent units thereof.
The above is effective for melt spinning polyester made of ethylene terephthalate. The present invention will be specifically explained below with reference to Examples. Example 1 A polyethylene terephthalate chip with an intrinsic viscosity of 0.63 measured at 25°C in an orthochlorophenol solvent was undrawn into a 135 denier 72 filament at a spinning temperature of 290°C, a discharge rate of 37.5 g/min, and a spinning speed of 2500 m/min. When spinning the yarn, a spinning oil with a concentration of 13% was measured at a rate of 2.0 cc/min using a metering pump, and the oil was supplied to the yarn using an oil applicator at a position 130 cm below the spinneret. In this case, the distance between the lower end of the yarn presser guide and the yarn focusing guide entrance is 450 cm, the distance between the yarn gathering guide entrance and the first godet roll is 50 cm, and the yarn focusing guide has a surface roughness of the shape shown in Figure 4.
Using a 1.5S high-purity alumina ceramic guide, the distance between the guides (a in Figure 4) was set to 4.5 cm, and the contact state (θ in Figure 4) between the yarn and the yarn convergence guide was changed. As shown in Table 1, the yarn tension (T ₁ ) and yarn tension (T ₂ ) at the exit of the thread presser guide are
The difference T was changed and continuous spinning was performed for 12 hours.
The results were as shown in Table 1. Note that Experiment Nos. 1 and 2 are comparative examples for clarifying the present invention.

[Table] Example 2 Using the same polyethylene terephthalate chips as in Example 1, the spinning temperature was 285°C and the discharge amount was 42.0g/
min, 126 denier at spinning speed of 3000m/min
When spinning undrawn yarn of 36 filaments, add 2.24cc/spinning oil of a 15% concentration aqueous solution using a metering pump.
The lubricant was measured at a rate of min and was filled with lubricant at a position 145 cm below the mouthpiece using a lubricant applicator. In this case, the distance between the lower end of the thread presser guide and the yarn focusing guide entrance is 260 cm, the distance between the yarn focusing guide entrance and the first godet roll is 70 cm, and the focusing guide has a surface roughness of 0.8S in the shape shown in Figure 5. Using a high-purity alumina ceramic guide, the distance between the guides (b in Figure 5) was set to 5 cm, and the contact condition between the yarn and the yarn convergence guide was changed to create a yarn presser as shown in Table 2. The difference T between the tension at the guide outlet (T ₁ ) and the yarn tension at the yarn convergence guide entrance (T ₂ ) was changed, and spinning was continued for 12 hours. The results were as shown in Table 2. Note that Experiment No. 5 is a comparative example for clarifying the present invention.

【table】 [Brief explanation of the drawing]

Figures 1 and 2 are front views showing conventional spinning machines using an oiling roll system and metered oiling system;
The figure is a front view of a spinning machine showing a preferred embodiment of the present invention. FIG. 4, FIG. 5, and FIG. 6 are a front view and a side view showing the yarn convergence guide in the present invention. 1: Spinning head, 2: Cooling device, 3: Cooling cylindrical duct, 4: Oiling roll, 5: First godet roll, 6: Second godet roll, 7: Oil applicator, 8: Yarn presser guide, 9: Floor (downstairs) ), 10:
Floor (upper floor), 11: Spinneret, 12: Yarn convergence guide, 13: Spun yarn, 14: Winding device.

Claims (1)

[Scope of Claims] 1. A yarn presser guide and a first
When performing melt spinning using a spinning machine in which the distance between the godet rolls exceeds 1.0 m, a yarn convergence guide is provided between the yarn presser guide and the first godet roll, and the yarn convergence guide at the exit of the yarn presser guide is A melt spinning method characterized in that the difference (T) between the tension (T ₁ ) and the yarn tension (T ₂ ) at the entrance of the yarn focusing guide satisfies formula (1). T≦0.2To＋0.8Tc ……………(1) However, T=T ₂ −T ₁ To is the theory of tension generated by air resistance between the yarn presser guide and yarn collection guide of completely unfocused yarn. It is a value and is calculated using equation (2). To= ^{0.37・Red -0.61 ・}(ρa/2)・π・V ²・D・n・L/980(g) ……………(2) Red: Reynolds number of filament Red=D・V・ρa・μa ^-1 D: Diameter of filament (cm) (In the case of yarn with irregular cross section, it is the equivalent diameter when converted to a round cross section) V: Spinning speed (cm/sec) n: Filament constituting the yarn (n is 2 or more) ρa: Standard air (temperature 20℃, absolute pressure 760mmHg,
Density at 75% relative humidity) 1.20×10 ^-3 g・cm ⁻³ μa: Standard air viscosity 1.82×10 ⁻⁴ g・cm ⁻¹・sec ⁻¹ L: Between the yarn presser guide and the yarn convergence guide entrance Distance (cm) Tc is the theoretical value of the tension generated by air resistance between the thread presser guide and the thread focusing guide of a completely focused thread, and is calculated by equation (3). Tc= ^{0.37・Redc 0.61 ・}(ρa/2)・π・V ²・Dc・L/980(g) ……………(3) Redc: Reynolds number of perfectly focused yarn Redc=Dc・V・ρa・μa ^-1 Dc: Diameter of circumscribed circle of perfectly focused yarn (cm)