JPH0152486B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for high speed spinning of viscose rayon. For high-speed spinning of viscose rayon, many flow bath spinning methods have been proposed in which the coagulation bath is made to flow in order to prevent the coagulation bath resistance from increasing and the strength and elongation of the yarn from decreasing as the speed increases. The problems that need to be overcome in high-speed spinning of viscose rayon are not only the strength and elongation of the yarn, but also the prevention of fuzz and cut threads, and the guarantee of uniformity of yarn elongation. Need to spin. The present inventors attempted to perform flow bath spinning using a flow tube with a funnel using a known method, but they faced any of the problems mentioned above and were unable to reach a satisfactory level as a production technology. The flow bath spinning method has not been able to reach industrial production. In view of the current state of the art, the present inventors have discovered that it is possible to spin viscose rayon at high speed and with high efficiency while ensuring uniformity of yarn strength, elongation, fuzz, cut yarn, and elongation. We once again started research on the flowing bath spinning method, focused on the relationship between the coagulation bath flow and yarn in a flow tube with a funnel, and completed the present invention as a result of intensive research. That is, in the present invention, when performing fluid bath spinning of viscose rayon using a funnel-equipped flow tube at a speed of 150 to 300 m/min, the spinneret is positioned within the funnel of the funnel-equipped flow tube whose inner surface is formed smoothly, The coagulation bath is introduced into a flow tube with a funnel with a distance between the spinneret face and the flow tube inlet of 20 to 60 mm, and the Reynolds number of the coagulation bath flow within 5 mm from the spinneret face is 500 to 2000. Viscose rayon high speed spinning method. The present invention will be explained in detail below. In the present invention, the flow tube with a funnel has a shape in which one end expands into a funnel shape, and a flow tube, which is a small diameter pipe, is joined to the narrowed point of the funnel to reach the other end. A spinneret is placed in a funnel, and the yarn discharged from the spinneret is flowed together with a coagulating bath flow in a flow tube with a funnel to perform flow bath spinning. First, it is important that the Reynolds number (Re) within 5 mm from the spinning face is 500 to 2000. When the Reynolds number in this region exceeds 2000, each single yarn running from the spinneret begins to sway independently at irregular intervals, and this sway becomes extremely large.
Its width is over 10mm. This wobbling propagates as the yarn travels, and does not disappear at the junction between the funnel and the flow tube, that is, at the flow tube entrance, and the yarn travels while hitting the inner wall of the flow tube with the funnel. The elongation of the yarn thus produced varies along the same yarn length direction, and a large number of fluffs occur due to long-term continuous operation, resulting in the occurrence of cut yarns. When the Reynolds number in this region is below 2000, there is no sway in the running yarn, and as a result,
There was no contact with the inner wall of the funnel-equipped flow tube, and the obtained elongation was highly uniform, even after long-term continuous operation.
The occurrence of fuzz and cut threads is almost improved to the level of normal industrial production. The present invention improves quality by limiting the Reynolds number of the coagulation bath flow in a limited area during flow bath spinning, and by combining the distance to the flow tube inlet and consideration of discontinuous contracted flow, which will be described later. This method allows yarn to be obtained efficiently at high spinning speed. In the present invention, 5
The Reynolds number of the coagulating bath flow at a point mm apart is less than 2,000, but the coagulating bath flow in a flow tube is more than 5,000, and in some cases reaches 25,000. Contrary to the suggestion that turbulence will occur in the flow of the coagulation bath unless the number is kept below 5000, this method does not impede spinnability in any way. A feature of the method of the present invention is that by setting the Reynolds number of the coagulation bath flow at a point 5 mm away from the spinneret to be low, the Reynolds number thereafter can be high, which facilitates high-speed spinning. The reason for this is probably that the surface coagulation of the ejected viscose is not sufficient up to a point 5 mm away from the spinneret surface, and in this region the yarn is extremely flexible, rather fluid. This is thought to be affected by turbulence in the coagulation bath flow. on the other hand,
The surface coagulation of viscose is extremely rapid compared to other wet spinning dope solutions. Therefore, the surface coagulation is completed after it is discharged from the spinneret and travels through the coagulation bath for about 5 mm, and from then on, the coagulation bath is disturbed. seems to be unaffected by the Although it is possible to reduce the Reynolds number of the coagulation bath flow to a point 5 mm away from the spinneret surface to less than 500,
The flow tube has a small diameter through which the yarn cannot pass through when it is being spun up, and a tube with a large funnel must be used, so it cannot be used industrially if workability is taken into consideration. Next, the space between the spinneret face and the flow tube inlet is set to 20 to 60 mm, and the coagulation bath is guided into the flow tube with a funnel without giving any discontinuous contraction to the coagulation bath. Discontinuous flow contraction occurs when the spinneret is placed outside the funnel, when there is a step in the middle of the funnel, or when the angle of divergence of the funnel changes midway through. In addition, "a funnel with a smooth inner surface" as used in the present invention means that the inner surface of the funnel that comes into contact with the coagulation bath has roughness, level difference, or widening to the extent that it causes discontinuous contraction in the coagulation bath liquid. This refers to something that does not have an intermediate change in angle. The contraction part that generates discontinuous contractions is 20 to 20 minutes from the spinneret.
When the coagulating bath flow reaches the flow tube inlet 60 mm away, the yarn slowly sways, which propagates in the yarn running direction, and this sway is amplified near the flow tube inlet. As a result, the threads were seen hitting the inner wall near the flow tube entrance, and fluff was formed on the threads. On the other hand, such yarn wobbling is not observed in the method in which no discontinuous contraction part is generated in the region. When continuous operation is carried out for a long period of time, the yarn obtained by the present invention has no defects, but in the method in which even a slight discontinuous contraction part is provided in the region, many small fluffs are observed. Probably, the accumulation of scum on the inner wall of the flow tube with a funnel, which always occurs in the spinning of viscose rayon, occurs over time, which causes contraction of the flow, resulting in yarn sway and yarn percussion. It is thought that the fluff is caused by the inner wall of the flow tube with the funnel, whose surface is covered with scum and loses its smoothness. When the distance between the spinneret surface and the flow tube inlet is less than 20 mm, the yarn sways to the flow tube entrance is large, the elongation of the obtained yarn is not uniform, and there is a lot of fuzz. Therefore, the distance from the spinneret surface to the flow tube inlet is 20 mm.
The above is necessary. If the thread is less than 20 mm, the surface coagulation of the thread is achieved, but the internal coagulation is insufficient, and as a result, the thread is flexible and is thrown around by the complicated flow at the flow tube entrance, causing defects. Seem. On the other hand, if the distance from the spinneret surface to the inlet of the flow tube becomes larger, there will be no problem in terms of yarn sway, but it will be difficult to center the spinneret and flow tube, and the parts will be large and difficult to handle. Problems such as too much resistance being added to the yarn may arise, so in reality this interval is
Must be 60mm or less. The Reynolds number (Re) of the coagulation bath flow in the flow tube is preferably set in the range of 11,000 to 25,000. If it is less than 11,000, it is difficult to increase the spinning speed, and if it is more than 25,000, the turbulence of the coagulation bath flow becomes large and fuzz occurs frequently. In the method of the invention, the flow of the coagulating bath in the flow tube is preferably 30 to 80 m/min lower than the velocity of the yarn within the flow tube. When the speed is lower than 80 m/min, the strength and elongation of the obtained yarn decreases due to the resistance of the coagulation bath.
Furthermore, if the difference is less than 30 m/min, the yarn cannot be separated from the coagulation bath after leaving the flow tube, making it difficult to take off the yarn. Further, it is preferable that the flow tube used has an inner diameter of 3 to 10 mm. If it is less than 3 mm, it will be difficult to perform thread stand work. If the diameter exceeds 10 mm, the size of the device will increase accordingly, the flow rate of the coagulation bath will become enormous, and the energy cost will increase. Also, the running direction of the yarn and the flowing direction of the coagulation bath are the same, but in this direction there are upward, downward,
Although it can be directed diagonally upward or diagonally downward, one embodiment of the present invention shows an embodiment directed downward. The method of the present invention described above will be further explained using an exemplary embodiment shown in FIG. The funnel-equipped flow tube consists of a funnel 3 and a pipe-shaped flow tube 4, which are joined at a joint 5 between the funnel and the flow tube. Place the spinneret 1 inside the funnel 3, and
is discharged from the spinneret, passes through the funnel 3 and through the flow tube 4. During this time, the coagulating bath flow flows together with the yarn 2 through the funnel 3 and the flow tube 4. In the method of the present invention, the Reynolds number (Re) of the coagulation bath flow up to 5 mm from the spinneret surface of the spinneret 1 in the yarn running direction 11 is set to 500 to 2000, and the funnel 3 has discontinuous contraction. A joint 5 between the funnel 3 and the flow tube 4 without providing a flow section is the flow tube inlet in the present invention. A viscose supply pipe 1 is attached to the spindle holder 12 that supports the spindle.
3 is connected. A box 8 for supplying a coagulation bath is provided with a coagulation bath supply pipe 10 that connects a spindle holder 12 and a flow tube with a funnel. The box 8 incorporates functional parts such as assembly and disassembly of the spinneret, but these are not shown. In addition, D ₁ in the figure indicates the funnel inner diameter (mm) at a point 5 mm away from the spinneret surface, V ₁ indicates the true coagulation bath flow velocity (m/mm), and D ₂ indicates the inner diameter of the flow tube. (mm)
, V ₂ represents the flow velocity of the coagulation bath in the flow tube (m/mm), and V ₃ represents the running speed of the yarn. Therefore, when the Reynolds number at a point 5 mm away from the spinneret surface is expressed as Re, the density of the coagulating bath flow for normal viscose rayon is 1.27 x 1000 Kg/m ³ and the viscosity is 0.001 Kg/m 3 .
m seconds, and Re = 1.27 x D ₁ x V ₁ x 1000/60. Next, the present invention will be explained by examples. Example 1 Viscose (cellulose 8
(wt%, cross-linked soda 6 wt%, falling ball viscosity 50 seconds, salt point 12, r number 40) and normal composition, coagulation bath (sulfuric acid 10 wt%, Glauber's salt 20 wt%, zinc sulfate 1.1 wt%, temperature
52℃), flow tube inner diameter 5 mm, flow tube length 800 mm,
The inner diameter of the funnel opening is 65 mm, the inner diameter of the flow tube inlet (junction between the funnel and the flow tube) is 5 mm, and the distance between the funnel opening and the flow tube joint is 60 mm. A funnel flow tube without a continuous constriction section was used, and the distance between the spinneret surface and the flow tube inlet was 50 mm. Next, 120 denier/26 viscose rayon
The filament was spun. Change the flow rate of the coagulation bath flow and set a point 5 mm away from the spinneret surface (the inner diameter of the funnel is 50 mm).
The Reynolds number of the coagulation bath flow (mm) was set at various levels, and Test Nos. 1 and 2 and Comparison 1 were used. The results are shown in Table 1. The Reynolds number (Re) of the coagulation bath flow at a point 5 mm away from the spinneret surface was set to 1500 and 2000, respectively, and test No.
1. It was set as test No. 2. Test No.1, Test No.2
In this case, the elongation unevenness σ of the yarn was less than 0.9, the yarn had little fuzz, and good results were obtained with no yarn wobbling during spinning. On the other hand, in Comparison 1 where the Reynolds number of the coagulation bath flow at a point 5 mm away from the spinneret surface is 2500, the elongation unevenness σ is 1.21.
It was large, had a lot of fuzz, and the yarn swayed a lot during spinning.

[Table] Example 2 Using the same viscose and coagulation bath as in Example 1,
120 denier/26 filaments of viscose rayon filament were spun. The flow tube with a funnel used had an inner diameter of 5 mm, a flow tube length of 800 mm, an inner diameter of the funnel opening of 110 mm, an inner diameter of the joint between the funnel and the flow tube of 5 mm, and a distance between the funnel opening and the joint of the flow tube. It is a funneled flow tube with a diameter of 35 mm, the inner surface of the funnel is smoothly formed, and there are no discontinuous contractions. Test No. 3 where the distance between the spinneret surface and the flow tube inlet was 20mm,
Comparison 2 used 17mm, and Comparison 3 used 40mm. At this time, the inner diameter of the funnel 5 mm away from the spinneret surface was 65 mm in Test No. 3 and 65 mm in Comparison 2.
It was 56 mm, and 110 mm in Comparison 3. The flow rate of the coagulation bath in the flow tube was 180 m/min, and the spinning speed was 220 m/min. The results are shown in Table 2. As is clear from Table 2, the Reynolds number (Re) of the coagulation bath flow at a point 5 mm away from the spinneret surface is 1465,
The distance between the spinneret surface and the flow tube inlet was set to 20 mm, and test No. 1 had no discontinuous flow contraction from the spinneret to the flow tube inlet.
In No. 3, the elongation unevenness σ of the yarn was 0.79, there was little fuzz, and good results were obtained with no yarn wobbling during spinning. On the other hand, the Reynolds number of the coagulation bath flow at a point 5 mm away from the spinneret face is 1695, and there is no discontinuous flow contraction part from the spinneret face to the flow tube inlet. In Comparison 2, which was set at 17 mm, the elongation unevenness σ was 1.56, which had a large variation, and there was a lot of fuzz, so favorable results could not be obtained. In addition, the Reynolds number of the coagulation bath flow at a point 5 mm away from the spinneret face is set to 861, the distance between the spinneret face and the flow pipe inlet is set to 40 mm, and the funnel opening becomes a discontinuous flow contraction part. In Comparison 3, there was a lot of fluff, and favorable results could not be obtained.

[Table] Re*1, V ₁ *2, V ₂ *3, Re* in Table 2
4. Elongation unevenness σ*5 and yarn wobbling*6 are the same markings as in Example 1. Example 3 Using the same viscose and coagulation bath as in Example 1,
120 denier/26 filaments of viscose rayon were spun. The distance between the spinneret surface and the flow tube inlet is set to 61
Test No. 4 and Comparison 4 were spun using flow tubes with different funnels using the above method. The flow tube with funnel used for test No. 4 had a flow tube inner diameter of 4 mm, a flow tube length of 1200 mm, and an inner diameter of the funnel opening of 74 mm.
mm, the inner diameter of the joint between the funnel and the flow tube was 4 mm, the distance between the opening of the funnel and the joint between the flow tube was 70 mm, and the inner wall of the funnel was free of discontinuous contractions. The funneled flow tube used in Comparison 4 has a flow tube inner diameter of 4
mm, the flow tube length is 1200 mm, the inner diameter of the funnel opening is 67 mm, the inner diameter of the joint between the funnel and the flow tube is 4 mm, and the distance between the funnel opening and the flow tube joint is 70 mm. In addition, there is a discontinuous constriction part on the inner wall of the funnel flow tube in Comparison 4.
Up to 14 mm from the opening, the angle of inclination of the inner diameter of the funnel is 4° with respect to the center line, and the inclination of the inner wall of the funnel from that point to the flow pipe inlet is 25°. The results are shown in Table 3. Test No. 4 obtained good results, but Comparison 4, which had a contraction section between the spinneret and the inlet of the flow tube, had a lot of fuzz and yarn sway, and did not give satisfactory results. .

【table】

[Table] Re*1, V ₁ *2, V ₂ *3, Re* in Table 3
4. Elongation unevenness σ*5 and yarn wobbling*6 are the same markings as in Example 1.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of an embodiment of the viscose rayon high-speed spinning method of the present invention. 1... Spinneret, 2... Yarn, 3... Funnel, 4...
... flow tube, 5 ... joint of funnel flow tube, 8 ... box,
10... Coagulation bath supply pipe, 11... Yarn running direction,
12... Spinneret holder, 13... Viscose supply pipe.

Claims (1)

[Claims] 1. When performing fluid bath spinning of viscose rayon at a speed of 150 to 300 m/min using a flow tube with a funnel, (a) a flow tube with a funnel whose inner surface is formed smoothly; (b) a funnel; (c) The space between the spinneret surface and the flow tube inlet is 20 to 60 mm, and the coagulation bath is guided into the flow tube with a funnel. (d) The coagulation bath flow is within 5 mm from the spinneret surface. A high-speed spinning method for viscose rayon characterized by setting the Reynolds number of 500 to 2000. 2 The flow rate of the coagulating bath in the flow tube is 30% higher than the running speed of the yarn.
The viscose rayon high-speed spinning method according to claim 1, characterized in that the spinning speed is as low as ~80 m/min. 3. The viscose rayon high-speed spinning method according to claim 1 or 2, wherein the inner diameter of the flow tube is 3 to 10 mm. 4 The Reynolds number of the coagulation bath flow in the flow tube is 11000~
25,000, the first claim is characterized in that
The viscose rayon high-speed spinning method according to item 2 or 3.