JPH09268428A - High-speed spinning of polyamide fiber yarn strand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-speed spinning method of polyamide fibers capable of prolonging a cleaning cycle of a spinnerets face and improving productivity in a high-speed melt spinning winding at >=2,000m/min. SOLUTION: In a melt spinning extruding a molten polyamide from spinnerets and winding at a high speed of >=2,000m/min to obtain fibers having 10-500 deniers in size, an extruding line velocity V1 (m/min) of the polyamide extruded from the spinnerets is made to be the formula: 4.5<=V1 <=15, and simultaneously a draft ratio D expressed by a ratio of a winding up velocity V2 (m/min) to the extruding line velocity V1 (m/min) (D=V2 /V1 ) is made to be the formula: 500<=D<=1,250.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for high-speed spinning of a polyamide fiber yarn, and more particularly, to a highly productive polyamide fiber yarn having improved stability of polymer discharge at the die discharge portion and excellent operation stability. The present invention relates to a high speed spinning method of a strip.

[0002]

2. Description of the Related Art In the melt-spinning method for synthetic fiber yarns such as polyamide, low molecular weight substances (monomers, oligomers, etc.) are sublimated from the polymer discharged from the spinneret, and these are deposited around the discharge holes, or the polymer is discharged. Matting agents such as titanium oxide and polymerization catalysts added to the above are deposited around the discharge holes and accumulate as stains around the discharge holes over time. Also,
Generally, a release agent such as silicone is applied to the surface of the melt-spinning die in order to enhance the release property of the polymer discharged from the discharge hole. However, this silicone does not retain the releasability permanently, and undergoes thermal deterioration and oxidative deterioration with time in a high temperature atmosphere, and finally becomes a gel state.

As described above, the accumulation of dirt around the discharge hole of the die and the gelling release agent destabilize the flow of the polymer discharged from the die and cause bending. If the tendency of the polymer to bend becomes extremely extreme, the polymer may discontinuously stick to the surface of the spinneret or may cause picking, which may cause yarn unevenness or yarn breakage due to fluctuations in the winding state.

Therefore, in the melt spinning method for the synthetic fiber yarn, it is usual that the spinneret surface is regularly cleaned before the above-mentioned deterioration of the spinnability occurs. However, since the cleaning of the die surface must be temporarily interrupted in production, the shorter the cleaning cycle, the lower the productivity. However, in recent years, in the melt-spinning method for polyamide fibers, in order to improve productivity, a so-called high-speed spinning method in which the yarn discharged from the spinneret is drawn at a high speed of 2000 m / min or more has been widely used. There is. However, in such a high-speed spinning method, since the amount of polymer discharged from the spinneret is large, the accumulation speed of dirt around the discharge hole is high, and as a result, the cleaning cycle of the spinneret surface is shortened and the productivity is improved. It was said that there was a limit.

[0005]

The object of the present invention is 20
In the high-speed melt-spinning method of taking over at 00 m / min or more,
It is an object of the present invention to provide a polyamide fiber yarn high-speed spinning method capable of improving productivity by extending the cleaning cycle of the spinneret surface.

[0006]

A high-speed spinning method for polyamide fiber yarn according to the present invention, which achieves the above object, discharges molten polyamide from a spinneret and draws it at a high speed of 2000 m / min or more, and a fineness of 10 to 500. in melt spinning method to obtain a denier yarn take-off relative to the discharge linear velocity V ₁ of the polyamide discharged from the mouthpiece of the (m / min) in the following equation (I), at the same time said discharge output line velocity V ₁ (m / min) Speed V ₂
(M / min) Draft ratio D (= V ₂ /
V ₁ ) is represented by the following formula (II).

4.5 ≦ V ₁ ≦ 15 (I) 500 ≦ D ≦ 1250 (II) In the present invention, the linear discharge velocity V ₁ (m / min) of the polymer means the polymer per unit time. Is the value obtained by dividing the discharge volume by the discharge cross-sectional area. Specifically, the density ρ of the molten polymer is 1 g.
/ Cm ³ means that defined by the following formula (III).

V ₁ = 4 × P / (ρ × π × T ² ) ... (III) However, P: Discharge rate per single hole of the die (g / min) π: Circular ratio T: Discharge of die Pore diameter (mm) Further, in the present invention, the take-up speed V ₂ (m / min) means the surface speed of the roller which is first drawn when the yarn discharged from the die is drawn by the godet roller, and When wound directly on a bobbin without passing through a godet roller, it means the winding speed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the high-speed spinning method of the present invention, the linear discharge velocity V ₁ (m of the polymer defined by the above formula (I) is used.
/ Min) and the draft ratio D defined by the above formula (II)
Are characterized in that the discharge linear velocity V ₁ is lower and the draft ratio D is significantly higher than those values generally adopted in the conventional high-speed spinning method.

In the conventional high-speed spinning method for polyamide fiber yarn, when a single yarn having a fineness of 10 to 500 denier takes up a yarn having a round cross section at a high speed of 2000 m / min or more, the draft ratio is about 300 at most. However, in the present invention, it is set to 500 or more. Therefore, in response to this, the linear velocity V ₁ (m / min) discharged from the spinneret is relatively lower than that of the conventional high-speed spinning method.

As described above, in the high-speed spinning of the polyamide fiber yarn, by setting the discharge linear velocity to be lower and the draft ratio to be higher than those in the conventional method, the discharge stability of the polymer discharged from the die is increased. In addition, it is possible to obtain toughness with respect to dirt around the discharge holes. Based on this, it is possible to reduce the occurrence of spiking of the length of the discharged polymer and the occurrence of yarn breakage,
It is possible to extend the cleaning cycle of the die surface.

Further, by setting the draft ratio to a very high value as in the formula (II), the polymer discharged from the die is contaminated by dirt and air flow formed by polymer sublimation gas around the discharge hole. It is possible to increase the resistance to. Specifically, since the rigidity of the polymer against bending is increased, the ejection stability is improved. On the other hand,
By setting the discharge linear velocity to a low value as in the formula (I), it is possible to suppress the heat generation due to the displacement of the polymer in the discharge holes, and it is possible to suppress the heat deterioration and the generation of dirt caused by the heat generation. .

In the high-speed spinning method of the present invention, when the draft ratio is lower than 500 or the discharge linear velocity is higher than 15 m / min, the rigidity against bending of the polymer at the spinneret discharge portion becomes low, so that The object of the invention cannot be achieved. When the draft ratio is higher than 1250 or the discharge linear velocity is lower than 4.5 m / min,
On the contrary, when the polymer is discharged from the discharge hole, the stability is lowered, so that yarn unevenness is likely to occur, or the spinnability is deteriorated to cause frequent yarn breakage.

In order to realize the above-described high-speed spinning method of the present invention, the diameter of the discharge holes is set so that the polymer discharge amount per single hole satisfies the formulas (I) and (II). is important. That is, the discharge linear velocity of the polymer is (I)
In order to lower the diameter as in the formula, it is necessary to increase the hole diameter of the discharge hole accordingly, but generally, when the diameter of the discharge hole is increased, the back pressure of the discharge hole may be reduced and uneven yarn may occur. As a means for maintaining the back pressure by increasing the diameter of the discharge hole, the length of the discharge hole may be increased as much as the decrease in the back pressure, or the hole diameter may be reduced before the polymer is introduced into the discharge hole. A zone for compensating the back pressure may be provided.

In the present invention, the fineness of the polyamide fiber to be produced is 10 to 500 denier, and the single yarn fineness is preferably 1.5 to 8 denier. If the single yarn fineness is smaller than 1.5 denier, the spinning tension under the spinneret becomes too high with the draft ratio in the range of the formula (II), and the yarn breakage tends to occur. Further, if the single yarn fineness is thicker than 8 denier, the rigidity of the polymer at the die discharge portion against bending is lowered, so that the effect of the present invention tends to be low.

The polyamide applied to the high-speed spinning method of the present invention is not particularly limited as long as it has fiber-forming properties, but among them, nylon 6, nylon 66 and a copolymer containing them as the main component are preferable. . Also,
The high-speed spinning method of the present invention can also be applied to the case where melt spinning is performed as a composite fiber having one of these polyamides as a component and the other as a polymer such as polyester other than polyamide.

Further, in these polymers, if necessary, a matting agent such as titanium oxide, various additives required for polymerization,
A heat resistance improver, an additive for controlling crystallization for the purpose of improving transparency, or a copolymerization component may be contained.

[0018]

EXAMPLE Nylon 6 chips containing 0.4% by weight of titanium oxide as a delustering agent and 98% sulfuric acid relative viscosity of 2.62 were melted at 260 ° C., and the molten polymer was filtered through a sand filter and a metal nonwoven fabric filter. Through the spinneret, cool the yarn after discharge with cooling air, apply the emulsion-based oil agent, and then take it off to the first godet roller at 5115 m / min, and then to the second godet roller at the same speed. After taking up, when taking up with a spindle drive type take-up machine with a take-up tension of 0.35 g / D, the ejection hole diameter and the ejection linear velocity of the die are made different as shown in Table 1 (back pressure of the die). There squeeze polymer inlet of the discharge hole to be constant of 50 kg / cm ^2, the downstream side is enlarged like a trumpet so as to have a predetermined discharge hole diameter, further circles polymer discharge direction at a predetermined pore size Was formed Jo straight portion), by changing the draft ratio, respectively total fineness 20,
Ten kinds of polyamide fiber yarns having different single fiber fineness of 35, 50 denier and 10 filaments were wound (Examples 1 to 5 and Comparative Examples 1 to 5).

About these 10 kinds of high speed spinning methods, 1
Take up 1 thread per spinner and wind 8 threads simultaneously into 1 winder. For a total of 4 winders, continuously wind for 5 days. And the wrinkle spots were evaluated using a Werster spot tester manufactured by Zellbeger. The results of the value are shown in Table 1.

As shown in Table 1, Example 1 according to the present invention
In Nos. 5 to 5, as compared with Comparative Examples 1 to 5, there was no occurrence of polymer bending or spiking in the die discharge hole portion due to day, the number of yarn breakages was small, and the yarn formability was extremely stable. In addition, the yarn unevenness was low and was at a level where there was no problem in quality.

[0021]

[Table 1]

[0022]

As described above, according to the high-speed spinning method for polyamide fiber yarns of the present invention, the discharge linear velocity of the polymer discharged from the spinneret is low and the draft ratio at the time of continuous drawing is high. Further, it is possible to increase the resistance to bending due to dirt around the discharge holes of the discharged polymer and the turbulence of the air flow, and to provide toughness. Therefore, it is possible to reduce the occurrence of bending and flicker of the discharged polymer in the mouthpiece ejection portion, and as a result, it is possible to extend the die cleaning cycle and improve the productivity.

Further, since the heat generated by the displacement of the polymer in the die discharge hole can be suppressed to a low level, the occurrence of stains around the die discharge hole due to the heat deterioration of the polymer can be reduced, and the stability of the spinning can be achieved for a long period of time. it can.

Claims (2)

[Claims] 1. A molten polyamide is discharged from a die and drawn at a high speed of 2000 m / min or more to obtain a fineness of 10 to 500.
In the melt spinning method for obtaining a denier yarn, the discharge linear velocity V ₁ (m / min) of polyamide discharged from the spinneret is set to the following formula (I), and at the same time, the discharge linear velocity V ₁ (m / min)
The method for high-speed spinning of polyamide fiber yarns, wherein the draft ratio D (= V ₂ / V ₁ ) represented by the ratio of the take-up speed V ₂ (m / min) to the above is set to the following formula (II). 4.5 ≦ V ₁ ≦ 15 (I) 500 ≦ D ≦ 1250 (II) 2. The method for high-speed spinning of a polyamide fiber yarn according to claim 1, wherein the single yarn fineness of the yarn is 1.5 to 8 denier.