JPH0157164B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved upflow bath spinning method for producing yarn by a wet spinning method. A spinning dope that can be wet-spun, including viscose, is discharged into a coagulation bath through a spinneret,
After being coagulated, it is pulled out from the bath and formed into a thread, which is then subjected to post-treatment as required to become a product thread. Conventionally, various fluid bath spinning methods have been proposed in which the coagulation bath is made to flow in the same direction as the running direction of the spun yarn in order to increase the spinning speed to increase productivity. As a method for manufacturing yarn, the spinning method described in Japanese Patent Publication No. 27-4931 is well known. Further, for example, upward flow bath spinning methods have been proposed as described in Japanese Patent Publication No. 30-8866, Japanese Patent Publication No. 5963-1983, Japanese Patent Publication No. 6058-1982, and Japanese Patent Publication No. 38-3956. This improves the space productivity of the equipment, and especially when spinning rayon yarn using the viscose method,
This is a favorable improvement in that the gas generated during spinning does not accumulate on the spinneret surface. However, all of the upstream bath spinning methods that have been proposed so far maintain the physical properties of the raw yarn at a good level and extremely reduce unevenness in the physical properties, especially in high-speed spinning. Seshime,
A method that simultaneously satisfies the conditions of significantly reducing process defects such as thread breakage and fluffing has not yet been found. For example, Special Publication No. 31-5963 or Special Publication No. 34
In Publication No.-6058 or Special Publication No. 38-3956,
The coagulation bath flowing out from the flow tube outlet is received in an overflow receiving tank larger than the flow tube outer diameter, or the flow tube inner diameter is gradually and continuously increased toward the flow tube outlet, or the coagulation bath is coagulated in the flow tube near the flow tube outlet. By drilling the bath outlet hole, the flow rate of the coagulating bath near the outlet of the flow tube is rapidly reduced, and a sudden bath resistance is applied to the yarn, which is still in a semi-coagulated state. Furthermore, the bath resistance vector near the outlet of the flow tube is distributed in a complicated manner in various directions other than the running direction of the yarn, and its direction changes from time to time. , is complicated and unsettling. Therefore, the semi-solidified surface of the still weak single yarn may cause minute damage due to rapid changes in bath resistance, or the complicated movement of the single yarn may cause stretching unevenness, resulting in yarn breakage, fuzz, etc. during the spinning process. process defects occur,
Furthermore, the physical properties of the product yarn after the post-treatment process, particularly the elastic properties such as dry elongation, wet elongation, Young's modulus, and shrinkage rate, deteriorate and unevenness occurs. For example, in the method described in Japanese Patent Publication No. 30-8866, the coagulation bath exiting the flow tube is once blown up into the air and then enters the overflow receiving tank, so a sudden decrease in the flow rate of the coagulation bath can be avoided. Since the coagulation bath is blown up vertically after the outlet of the flow tube, the height and direction of the top of the blown up coagulation bath fluctuate with time, and the yarn, which is still in a semi-solidified state, is not a coagulated yarn. When the yarn passes through the top of the blown coagulation bath, it is affected by complicated oscillations, which causes stretching unevenness, and thus causes unevenness in the physical properties of the product yarn, especially in its elastic properties. In this method, in order to suppress temporal fluctuations in the height and direction of the top of the coagulating bath that is blown up, it is sufficient to reduce the length of the blown up coagulation bath. In other words, the bath resistance increases and it becomes impossible to obtain satisfactory physical property values. As a result of intensive research to solve the above-mentioned drawbacks that could not be overcome with conventional methods, the present inventors discovered that the direction of flow is extremely important when causing a coagulation bath to flow upward, and thus arrived at the present invention. This is what I did. That is, in the present invention, the flow tube is provided with an inclination angle (Θ) of 5 to 20 degrees with respect to the perpendicular line, and the coagulating liquid flows from the flow tube outlet in a cylindrical shape according to the flow velocity (V) in the flow tube. This is an upflow bath spinning method characterized by a finite length (H) expressed by the following formula being sprayed into the air in the direction of inclination of the tube. H=V ² /(2g cosΘ) (However, g represents gravitational acceleration.) According to the method of the present invention, the physical properties of the yarn can be maintained at a good level, and unevenness in the physical properties can be extremely reduced. It can significantly reduce process defects such as yarn breakage and fluff, and is particularly useful in high-speed spinning. An example of an embodiment of the present invention is shown in FIG. The present invention will be explained in detail with reference to FIG. The spinning dope passes through a spinning dope introduction pipe 4 and a spinneret 6 installed on a spinneret support 5.
The flow tube 8, which is installed at an angle of inclination of 5 to 20 degrees with respect to the perpendicular to the ground surface, is discharged into the coagulation bath introduced through the coagulation bath introduction tube 2 and forms a semi-coagulated thread 7. H=V ² /(2g cosΘ) in the air, passing through the interior together with the coagulation bath, from the outlet of the flow tube in a cylindrical shape toward the direction of inclination of the flow tube 8, as shown in FIG.
(However, g represents gravitational acceleration.) It is ejected over a finite length (H). After being completely coagulated while passing through the blown-up coagulation bath 9, it reaches the top of the blown-up coagulation bath 9 and becomes a coagulated thread 10, which is taken off to be subjected to post-treatment as required. In the present invention, the reason why the blown-up coagulation bath 9 is blown up into the air over a finite length (H) is as follows. That is, if the angle between the perpendicular 11 to the earth's surface and the inclination line 12 of the flow tube is θ, then the coagulation bath passing through the flow tube 8 in the direction in which the yarn travels at a flow rate of V is
A flow velocity V equal to the flow velocity within the flow tube from the outlet of the flow tube 8
is pushed out. After that, as is well known in elementary mechanics, when the gravitational acceleration is g, the liquid is blown up to a length H of H=V ² /(2g cosθ), and at the top of the blown-up coagulation bath, the flow velocity becomes 0 and it begins to fall. Therefore,
The yarn, which has not yet completely coagulated at the time of passing through the outlet of the flow tube 8, is blown up to reach the top of the coagulation bath 9 to complete coagulation. A very slow decrease in velocity proportional to /2, i.e. a very slow bath resistance (external force)
will only experience an increase in Furthermore, the speed reduction rate of the blown-up coagulation bath is gradual as it approaches the outlet of the flow tube. That is, in the region where the degree of coagulation of the yarn is relatively low, the increase in external force is small, and as the coagulation of the yarn becomes sufficient, the increase in external force increases. growing. Therefore, in areas where the surface of the yarn is insufficiently coagulated, the external force applied to the surface is small, so damage to the semi-solidified surface and uneven stretching are less likely to occur.On the other hand, in areas where a large external force is applied, the yarn It goes through an extremely rational process in which large surface damage and stretching spots no longer occur because the coagulation has progressed sufficiently. Furthermore, as the spinning speed increases, it becomes necessary to increase the flow rate in the flow tube in order to maintain a good level of physical properties, so it is more advantageous and necessary for the yarn to undergo the above steps. it is obvious. The coagulation bath referred to in the present invention is cylindrical from the flow tube outlet toward the inclination direction of the flow tube, and has a finite length (H) in the air.
Being blown up is the basic principle for producing the above phenomenon.
For example, an overflow receiving tank having a cross-sectional area larger than the cross-sectional area of the flow pipe provided in series with the flow pipe, or a funnel pipe whose cross-sectional area increases as it advances;
Alternatively, by providing a perforated flow tube or the like, the coagulation bath flowing out from the flow tube is caused to overflow in a so-called overflow, thereby preventing the coagulation bath from decreasing rapidly. Refers to a device that is connected in a series and has a blown-up coagulation bath of a finite length in the direction of thread movement from the outlet of the component into which the coagulation bath is flowing.
The intended length of the blow-up bath should be determined by the spinning speed, the desired level of physical properties, or the setpoint of the flow rate of the coagulation bath in the flow tube. or,
In order to spray the coagulation bath up a finite length (H) into the air in a cylindrical shape from the outlet of the flow tube, it is necessary to pressurize the coagulation bath in some way, for example, by forcibly pumping the coagulation bath, Alternatively, it is preferable to blow it out by head pressure. However, it is still difficult to bring the unevenness of physical properties to a level that does not pose any problem when using the product yarn just by providing a jet of coagulation bath of finite length (H). Although the upstream bath spinning method proposed in the past has the concept of causing the coagulation bath to flow upward, it is nearly impossible to obtain a product yarn with sufficient homogeneity for practical use using this technique alone. This is because when the blown-up coagulation bath is blown up perpendicular to the ground surface, variations in gravity acting on the blown-up coagulation bath, bath speed, yarn running, etc. affect each other in a complex manner, resulting in The height and direction of the vertex, that is, the vertex position, changes moment by moment with time. A familiar example of this phenomenon is that it is easily observed in the case of vertical fountains in parks and the like. Therefore, in the upflow bath spinning method using the blow-up method, the flow tube has an inclination angle with respect to the perpendicular line 11 to the ground surface in order to suppress the positional fluctuation of the top of the blow-up coagulation bath and to extremely reduce stretching unevenness. It is necessary that the coagulation bath is spouted in that direction. According to the results of detailed research by the present inventors, the inclination angle θ is 5
It is necessary to be in the range of 20 to 20. If θ is too small, the apex position of the jet coagulation bath 9 will be difficult to determine as described above, and the tension applied to the yarn will vary greatly in magnitude and direction, resulting in poor physical properties of the product yarn, especially dry elongation and wet Unevenness in elastic properties such as elongation, Young's modulus, and shrinkage rate tends to occur along the yarn length direction.On the other hand, if the angle θ is too large, equipment space per weight increases, resulting in equipment productivity. Moreover, the necessary working area becomes large, the spinning operation becomes frequent, and production on an industrial scale becomes somewhat difficult. Furthermore, the width of the apex of the blown-up coagulation bath expands and constantly fluctuates, and furthermore, external force due to the falling coagulation bath begins to be applied to the yarn running in the blown-up coagulation bath, ensuring smooth running of the yarn. It becomes difficult to be treated. Therefore, in order to suppress the fluctuation in the position of the apex of the blown-up coagulation bath, to extremely reduce stretching unevenness, and to facilitate production on an industrial scale, it is necessary to provide a flow tube with an inclined angle and It is necessary to spray the coagulation bath in that direction, and more preferably the inclination angle θ is in the range of 5 to 20 degrees. As described above, the present invention provides a flow tube having an inclination angle with respect to the perpendicular to the ground surface, and the coagulation bath is directed from the outlet of the flow tube in the direction of the inclination of the flow tube at the flow velocity within the flow tube, so that the coagulation bath is intentionally suspended in the air. The upflow bath spinning method, which is characterized by the fact that the yarn is blown up, maintains the physical properties of the raw yarn at a good level, extremely reduces unevenness in the physical properties, and also prevents damage to the yarn surface. Since there is no unevenness or drawing unevenness, the product yarn can be produced stably and easily on an industrial scale, especially during high-speed spinning, with greatly reduced process defects such as yarn breakage and fuzz. The present invention will be explained below with reference to examples, but the present invention is not limited to the following examples. Example 1 Viscose with a cellulose concentration of 8.0% by weight and an alkali concentration of 5.5% by weight, produced by a conventional method,
150g of H ₂ SO ₄ produced in the usual way,
In a coagulation bath of 280 g of Na ₂ SO ₄ and 15 g of ZnSO ₄ at 52°C, a spinning method of 200 m/
A 120 denier yarn was spun at a spinning speed of 120 min.
The spinneret was 0.06 mmφ x 26 holes (made of platinum), and the flow tube was a glass tube with an inner diameter of 5 mm and a length of 100 mm. The coagulated and spun yarn passed through a thread path and rollers, was wound up into a centrifugal pot, and was subjected to standard post-processing to form a product filament. Based on the number of thread breakages (times/weight/day) and the warper-type fluff detection method when the inclination angle θ of the flow tube was varied from 0 to 25 degrees and the coagulation bath jet length H was varied from 100 to 500 mm. Measured number of fluff (pieces/10 ⁶ m)
are shown in Tables 1 and 2, respectively. Furthermore, as a representative physical property value, the dry elongation of the yarn was continuously measured every 1 m over 100 m using a continuous strength and elongation measuring device (Type 96) manufactured by Wooster. Table 3 shows the average value and standard deviation value σ of the dry elongation of the yarn when the inclination angle θ of the flow tube and the top length H of the coagulation bath were varied.

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[Table] Comparative Example 1 Continuously connected to the outlet of the flow tube 8 shown in Fig. 1, the inner diameter
A cylindrical overflow receiving tank of mm is provided, 20 mm from the flow pipe outlet.
H=100, 300 in Example 1 when the inclination angle θ of the flow tube was set to 0 and 12 degrees, except that the coagulation bath was overflowed at the height of . ,500mm
Spinning and evaluation were performed at a flow rate within the flow tube section of 5 mmφ corresponding to . The flow rate is expressed as the equivalent H length in the table below for easy comparison. Number of thread breakages (times/weight/day) and number of fuzz occurrences (pieces/10 ⁶ m)
are shown in Tables 4 and 5, respectively, and Table 6 shows the average and standard deviation values of dry elongation.

【table】

【table】

[Table] From the above Example 1 and Comparative Example 1, it is clear that the upflow bath spinning method of the present invention has extremely few process defects, is sufficiently homogeneous for practical use, and is significantly superior to the conventional method. It is clear that the product is intended to provide a product yarn with a high quality.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of the implementation of the present invention. 1 is the direction of coagulation bath introduction, 2 is the coagulation bath introduction pipe, 3
is the spinning dope introduction direction, 4 is the spinning dope introduction tube, and 5 is the spinning dope introduction tube.
is a spinneret support, 6 is a spinneret, 7 is a semi-coagulated thread, 8 is a flow tube, 9 is a blow-up coagulation bath, 10 is a coagulated thread, 11 is a line perpendicular to the ground surface, and 12 is an inclination line of the flow tube. .

Claims (1)

[Claims] 1. A flow tube is provided with an inclination angle (Θ) of 5 to 20 degrees with respect to the perpendicular line, and the coagulating liquid is cylindrical from the flow tube outlet due to the flow velocity (V) in the flow tube. An upflow bath spinning method characterized in that a finite length (H) expressed by the following formula is spouted into the air in the direction of inclination of the flow tube. H=V ² /(2g cosΘ) (However, g represents gravitational acceleration.)