JPH0639723B2 - Visco-Rayon Flow Tube Spinning Method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a flow tube spinning method for viscose rayon.

Conventional technology In high-speed spinning using a wet spinning method such as viscose rayon or copper ammonia rayon, the bath resistance of the coagulation bath increases with the increase in spinning speed, and excessive tension acts on the yarn to improve the yarn quality. There is a problem of decrease. In order to solve such a problem, a flow tube type spinning method in which a yarn is made to flow in a thin tube together with a coagulating liquid is used. In this flow tube spinning method,
To obtain a thread quality that is practically satisfactory, Japanese Patent Publication No. 45-2
As seen in Japanese Patent No. 5336, it is necessary to maintain the flow velocity of the coagulating liquid in the flow tube at a high speed which is about 30 to 80 m / min slower than the spinning speed. Therefore, as the spinning speed increases,
The coagulating liquid flow rate must be increased, and the coagulating liquid flow rate naturally increases accordingly. The problem that accompanies an increase in the flow rate of the coagulating liquid is the irregular fluctuation of the yarn from the spinneret to the inlet of the flow tube. The non-uniform force is applied to the yarn which is not subjected to extremely damage and causes fluffing or, in a remarkable case, yarn breakage. In order to prevent the yarn from swaying, the spinneret and the flow tube are usually arranged to gradually increase the flow rate of the coagulating liquid between the spinneret and the inlet of the flow tube, as disclosed in Japanese Patent Publication No. 45-25336. It is common practice to make the coagulation bath section between and into a conical funnel shape.

However, according to the research conducted by the present inventors, even when such a method is used, if the spinning speed is set to a high spinning speed of 250 m / min or more, the fluctuation of the yarn cannot be completely prevented, and this fluctuation occurs. As a result, the yarn immediately after discharge, that is, in the process of forming the initial structure of the fiber, suffers structural destruction, which leads to a decrease in yarn physical properties, particularly elongation, and it is unavoidable that the yarns frequently have many fluffs. It was the current situation. Therefore, with the recent advances in weaving processing technology, it has been possible to obtain only extremely unsatisfactory qualities from the high quality requirement levels required for raw yarns.

The present inventors have studied many technical factors in order to solve the above-mentioned problems, and as a result, as a result, yarn fluctuations occurring between the spinneret and the flow pipe inlet in such a high spinning speed region. Found that the main cause was the vortex flow generated during the rapid contraction of the coagulating liquid at the inlet of the flow tube. That is, it has been found that, in order to prevent the generation of this vortex, it is extremely effective to provide a flow straightening plate for straightening the coagulating liquid at the inlet of the flow pipe.

Means and Actions for Solving the Problems An object of the present invention is to provide a flow tube spinning method of viscose rayon for producing high quality rayon yarn by eliminating the yarn fluctuation generated between the spinneret and the flow tube inlet. To provide.

In order to achieve the object of the present invention, in a viscose rayon flow tube type spinning method, when arranging a plurality of straightening vanes at equal intervals around a flow pipe inlet, as the straightening vanes, (1) thickness t Is 0.3 mm or less, (2) the length ls is 10 mm or more, (3) and the height h (mm) is twice or more the flow tube inner diameter D (mm). The distance 1 (mm) between the downstream end of the straightening plate and the inlet of the flow tube is the inner diameter of the flow tube D (m
m) and the spinning speed is 250 m / min or more, and the viscose rayon flow tube spinning method is used.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view of a flow tube used in the present invention, and FIG. 2 is a plan view showing an arrangement state of the current plate shown in FIG.

In the figure, 1 is a viscose supply pipe, and the viscose supplied from this is discharged from the spinneret 2 to the coagulating bath funnel-shaped portion 8. The coagulation liquid is supplied from the coagulation liquid supply port 3 and flows downward. The viscose discharged from the spinneret forms a yarn 5, flows down with the coagulating liquid flowing down the conical portion 4, and is introduced into the flow tube 7. Reference numeral 6 is a coagulating liquid rectifying plate, which is arranged at equal intervals around the inlet of the flow tube. FIG. 2 shows the current plate 6.
Shows the arrangement state of.

The most important thing about this straightening plate is its thickness t,
It is desirable to make this as thin as possible, but according to the study by the present inventors, in order to obtain a substantially effective rectifying effect,
It must be 3 mm or less. If it is more than this, turbulent flow is generated at the downstream end of the straightening vane. Further, in order to obtain an effective rectification effect, eight or more rectification plates are required. If the number of sheets is less than this, the distance between the flow straightening plates becomes too large and an insufficient flow straightening effect is obtained. It is necessary that the length ls of the current plate be 10 mm or more. Below this, a sufficient rectifying effect cannot be obtained. Further, the height h of the flow straightening plate needs to be increased if the inner diameter D of the flow tube is large, and is preferably twice or more the inner diameter D of the flow tube. In the case of not more than twice, the flow of the coagulating liquid passing through the upper part of the straightening vane and flowing into the flow tube becomes relatively large, and the function of the straightening vane cannot be sufficiently exhibited. Furthermore, the present inventors have made a very important discovery as a result of detailed examination of the installation of the current plate. That is, the distance 1 between the downstream end portion 9 of the straightening vane and the flow pipe inlet portion 10 has a great relation to the prevention of yarn fluctuation, and this distance is set to 0.3 times or more and 0.8 times or less of the flow tube inner diameter D. By doing so, it has been found that the best rectification state can be obtained. If it is installed at a position exceeding 0.8 times, the liquid passing through the downstream end 9 of the straightening plate causes a contraction of the coagulation liquid before reaching the inlet of the flow tube, and the coagulation liquid flow in the contraction process. Due to the change in the velocity gradient, the stir flow is generated due to the inversion phenomenon of the liquid, causing the yarn to shake. Further, although the reason why the yarn deviation increases in a region where the distance 1 is less than 0.3 times the inner diameter D of the flow tube is not clear, smooth formation of the contracted streamline of the coagulating liquid flow at the inlet portion 10 of the flow tube is not possible. It is presumed that the presence of the straightening vane just before the inlet of the flow pipe hinders it.

EXAMPLE Viscose (8% by weight cellulose,
6% by weight of caustic soda, falling ball viscosity of 50 seconds, salt point of 12, γ value of 40) and coagulation bath of ordinary composition (10% by weight of sulfuric acid, 20% by weight of sodium sulfate, 1.1% by weight of zinc sulfate, temperature of 52 ° C.) 120 denier / 40 filament viscose rayon filament at a spinning speed of 300 m / min.
Under the conditions shown in the table, the fiber was spun by a flow tube type spinning device, continuously introduced into a drum type continuous spinning device, subjected to a scouring treatment, dried and wound. The flow tube used had a length of 1,000 mm.

In spinning, the results shown in Table 1 were obtained with respect to the physical properties of the spun yarn and the number of fluffs by changing the number, thickness, and shape of the straightening vanes, the distance between the lower end of the straightening vanes, and the inlet of the flow tube. It was Experiment No. 1 in Table 1 is a condition in which a straightening vane is not used.

As can be seen from Table 1, in Experiment No. 1, no rectifying plate was used, but the physical properties of the obtained yarn were low in both strength and elongation, and many spinning fluffs were generated. On the other hand, in Experiment Nos. 2, 3 and 4 in which the spinning method of the present invention was carried out, the yarn properties of the obtained yarn were high in both strength and elongation, and the generation of spinning fluff was small. Experiment No. 5 using a straightening vane, but spinning under a condition outside the range of conditions in the spinning method of the present invention
In the comparative examples shown in to 11, the occurrence of spinning fluff is large.

Advantages of the Invention In the flow tube type spinning of viscose rayon, the yarn fluctuation generated between the spinneret and the flow tube inlet is eliminated to improve the yarn characteristics, and particularly, the generation of spinning fluff is reduced to 1/10 or less of the conventional value. It is effective in providing a spinning method that can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of a flow tube used in the present invention, and FIG. 2 is a plan view showing an arrangement state of the current plate shown in FIG. 1 ... Viscose supply pipe, 2 ... Spinneret, 3 ... Coagulating liquid supply port, 4 ... Conical portion, 5 ... Thread, 6 ... Straightening plate, 7
...... Flow tube, 8 ...... funnel-shaped section, 9 ...... Downstream end of straightening plate,
10 ... Flow pipe inlet

Front page continued (72) Inventor Shinichi Uematsu 6-4100 Asahi-cho, Nobeoka, Miyazaki Prefecture Asahi Kasei Kogyo Co., Ltd. Examiner Toranosuke Hashimoto (56) References Japanese Patent Publication No. 35-5667 (JP, B1)

Claims (1)

[Claims] 1. In a viscose rayon flow tube type spinning method, when arranging a plurality of straightening vanes at equal intervals around a flow pipe inlet, as the straightening vanes, (1) the thickness t is 0.3 mm or less. (2) A straightening plate having a length ls of 10 mm or more, (3) and a height h (mm) of at least twice the inner diameter D (mm) of the flow tube is used. The distance l (mm) between the downstream end of the pipe and the inlet of the flow pipe is
m) and the spinning speed is 250 m / min or more, and the viscose rayon flow tube spinning method is provided.