US3219740A - High speed tubular spinning of fine viscose rayon yarn - Google Patents

Description

Nov. 23, 1965 HiDEO HATA ETAL 3,219,740

HIGH SPEED TUBULAR SPINNING OF FINE VISCOSE RAYON YARN Filed May 21, 1962 COAGULAT/NG L/OU/D STRETCH/N6 MEMBER 2 6/ 6 W0 1.. N F /mu m C F/RST ROTA Tl/VG MEMBER TANG'E/VT/AL FLOW TUBE WOUND Y4 RN INVENTOR H/DEO HA 7/] H/TOSH/ TONAM/ ATTORNEY United States Patent 3,219,740 HIGH SPEED TUBULAR SPINNING OF FINE VISCOSE RAYON YARN Hideo Hats, Hitoshi Tonarni, and Ryuichiro Koide, Iwakuni-slii, Yamaguchi-ken, Japan, assignors to Teihoku .linzo Kenshi Kabushiki Kaisha, Osaka, Japan, a corporation of Japan Filed May 21, 1962, Ser. No. 196,500 Claims priority, application Japan, May 23, 1961,

8 Claims. (Cl. 264-180) This invention relates to .a high speed tubular method of spinning fine viscose rayon yarn.

Nowadays when the trend is for high-class fabrics, there is also a demand for fine yarns in case of rayon also. However, the finer the yarn becomes, the quantity produced per unit spindle falls and as a result raises the cost. Thus, there is an urgent demand for the high speed spinning of fine yarn Whose yarn quality equals or surpasses that of the ordinary yarn.

The present invention has answered this demand, being related to a method of spinning at high speeds of above 180 m., particularly above 200 111. per minute, a fine yarn of less than 75 deniers. According to this *invention, even a fine yarn of such as 20 deniers can be spun at above 200 m. per minute and moreover with a yarn quality equal to or surpassing that spun by the conventional method.

Heretofore, as the method of spinning at relatively high speeds viscose rayon yarn, particularly high tenacity yarn, the so-called tubular spinning method such as that described, for example, in F. R. Milhiser US. Patent 2,440,057 was known.

The Millhiser method of spinning viscose rayon yarn comprises extruding viscose through a spinneret into a coagulating bath to produce a continuous filament yarn, stretching the resulting yarn at a tension not to exceed 0.06 gram per denier until said tension will no longer impart a substantial stretch to the yarn, causing coagulating bath to flow in the direction of movement of the yarn, maintaining said yarn in cocurrent contact with said coagulating bath at a tension of between 0.01 and 0.06 gram per denier until it will withstand a tension of at least 0.5 gram per denier, with the yarn travelling at a speed slightly in excess of the speed of the cocurrent coagulating bath liquid, and then stretching said yarn. When tubular spinning is carried out at a spinning speed of above 200 m./min., the how of the liquid is bound to become to a certain extent a turbulent flow. This is because no matter how much the other conditions are controlled the Reynolds number of the liquid flow becomes more than 5000 and also because the yarn passes through the liquid. If the yarn is caused to maintain contact with the coagulating bath liquid for a long period of time until it will withstand a tension of 0.5 gram per denier, the yarn will be imparted a considerable amount of a nonuniform permanent deformation by means of this turbulent flow and the yarn quality will be lowered. In spite of this, in the Millhiser process the yarn had to be maintatined in contact with the coagulating bath liquid for a relatively long period of time (until it will withstand a tension of 0.5 gram per denier). This is believed to be due to the following reason.

In a thick yarn of about 150 deniers such as shown in the example of the Millhiser process, when the diameter of the tube is small the yarn rubs against the tube wall and the yarn quality is impaired. Thus, for preventing this, the diameter of the tube must necessarily be made large. In such a case, since the amount of liquid that is discharged at the outlet of the tube becomes large, the force that the yarn is subjected to when it separates from the liquid also becomes large. The yarn must have become such that it can withstand this force. And since the finer the yarn or the more the spinning speed is raised the force that the yarn is subjected to when it separates from the coagulating bath liquid becomes greater, the necessity arises of imparting to the yarn a strength sufiicient to withstand this force.

Therefore, it is very difficult to spin at high speeds fine yarn of less than deniers by following the Millhiser process.

Accordingly, one of the principal objects of the present invention is to provide a method of manufacturing fine viscose rayon yarn of less than 75 deniers.

Another object of the invention is to provide a method of manufacturing at high speeds fine viscose rayon yarn of less than 75 deniers.

A further object of the invention is to provide a tubular spinning method of viscose rayon yarn that can spin fine yarn of good quality at high speeds.

Other objects and advantages of the present invention will become apparent from the following description when taken in connection with the accompanying drawing, in which:

FIGURES 1 and 2 illustrates two embodiments for carrying out the process of the instant invention.

FIGURE 3 illustrates the tangential flow of the coagulating fluid with respect to a first rotating member.

FIGURE 4 illustrates a non-tangential flow of coagulating fluid.

These objects and advantages of this invention, as described hereinabove, are attained in the tubular spinning of fine viscose yarn of less than 75 deniers comprising extruding viscose through a spinneret into a coagulating liquid thereby forming continuous filament yarn, passing said yarn through a tube together with the coagulating liquid, discharging said yarn from said tube together with the coagulating liquid and winding up said yarn on a first rotating member followed by stretching said yarn, by a method characterized in that the viscose is extruded into the coagulating liquid in such a manner that the draft D satisfies with respect to the peripheral speed V m./min. of a first rotating member the condition that said tube whose diameter throughout its entire length is substantially the same has an inside diameter of 3-7 mm, that said yarn and coagulating liquid are passed through the tube at substantially the same speed, that the regeneration value of the yarn at the time of its being wound up on the first rotating member is below 20%, and that said first rotating member is disposed tangentially to the line of the coagulating liquid and has a peripheral speed V of -300 m./min.

What is referred to as the draft in this invention is represented by a value that is obtained by dividing the peripheral speed of the first rotating member with the average speed of the viscose in the holes when it is being extruded from a spinneret.

And the spinning speed is represented by the peripheral speed of that rotating member located immediately before the windup means, this normally being the second rotating member which follows the effecting of stretching operations.

What is referred to as the regeneration value is represented by the formula l-residual '7 value of the yarn/'y value of viscose, the "p value of viscose being measured by the conventional film method or ion exchange method. The residual '7 value of the yarn was measured according to the following procedure.

Namely, a V-shaped inclining bath through which is flowed a regeneration stopping liquid (an aqueous solution of sodium chloride and sodium acetate) maintained at below C. is disposed between the first and second rotating members, and the yarn is wound up on the second rotating member to collect the sample. This is immediately washed thoroughly with a cooled saturated aqueous solution of sodium chloride (a completely neutral one being used), added to an aqueous sulfuric acid solution of known concentration, followed by thoroughly heating with shaking in a water bath and thereafter measuring the decrease in concentration of the sulfuric acid. The regeneration value at the time when the yarn is to be wound up on the first rotating member is represented by a value obtained by measuring several times after having changed the number of turns on the first rotating member and extrapolating for the value of the zero number of turns.

The rate of flow is indicated with the rate of flow of the liquid at that part inside the tube where the yarn passes.

The first essential of this invention resides in the point that the regeneration value of sodium cellulose Xanthate in the yarn does not exceed 20% at the time when the yarn is to be wound up on the first rotating member. Thus, in the present invention, since the residence time of the coagulated yarn in the turbuelnt zone is short and moreover a yarn of small regeneration value is not easily imparted permanent deformations, the lowering in yarn quality due to turbulent flow can be avoided. However, the strength of a yarn with a regeneration value below 20% is not entirely sufficient and when such a yarn is discharged in a large amount from the tube together with the coagulating liquid, breakage in the yarn occurs. We have solved this point by making the inside diameter of the tube 3-7 mm. thereby reducing the amount of the coagulating liquid whereby has been made possible a reduction in the force that the yarn is subjected to when separating from the liquid. In addition, by disposing the first rotating member tangentially to the outflow of the: coagulating liquid, we have succeeded in lessening still more the force that the yarn is subjected to when separating from the liquid. In this instance, if the tube is held in. a position that inclines 45-90 degrees to the horizontal plane, it is still more desirable. At high speed spinning, of such as above 200 m./min., as breakage of the yarn at that part near the spinneret is likely to occur very frequently, it is necessary that the draft D be made small such that it will satisfy the condition V'+200D 4l0. Although making the draft small is practiced in spinning high tenacity yarn, in case of ordinary yarn it is not generally practiced.

According to the present invention, since the spinning speed is fast, the distance that the yarn travels, after extrusion of the viscose and a coagulated skin of a hardness that determines the sectional configuration of the viscose forms on its surface, becomes greater. Because the yarn is disturbed by the flow of the liquid While the foregoing coagulated skin is still soft, it inevitably results that the higher the speed, the flatter the sectional configuration of the yarn becomes. Hence, in the present invention it is best to provide a coagulating bath such as will form the coagulated skin promptly. If the concentration of the sulfuric acid (g./l.) in the coagulating bath is less than 1.7 times the concentration of the total alkali (g./1.) in the viscose, drawbacks such as flattened section, unsatisfactry state of spinnin-g, etc. occur.

On the other hand, if it is more than 2.6 times, filament formation in which regeneration has preceded by means of H SO occurs whereby lowering of the yarn quality, especially a rise in the swelling value, results. Therefore, the sulfuric acid concentration in the coagulating bath is preferably 1.7-2.6 times, particularly 2.0-2.3 times, the concentration of the total alkali in the viscose. Moreover, in case of a spinning method in which the sulfuric acid concentration is comparatively high, if the concentration of salts (g./l.) in the coagulating bath is less than 1.8 times that of the sulfuric acid, the regenerative effects will precede the coagulation. On the other hand, if the concentration of salts is more than 2.7 times, the coagulation effects will precede. Therefore, the concentration of salts in the coagulating bath should preferfably be 1.8-2.7 times, particularly 2.1-2.4 times that of the sulfuric acid.

Preferred as the temperature for the coagulating liquid is a temperature somewhat higher than that of the conventional coagulating liquid for viscose. That is to say, the temperature of the coagulating liquid may be from 55 to 60 C.

As regards the tube employed in this invention, what is meant by about the same diameter throughout its length is that it does not taper nor flare toward its front end; the inlet for the yarn however includes those that are flared for prevent-ing the setting up of a turbulent flow. The reason why the diameter of the tube must be uniform is that when it is not, changes in the rate of flow occur, and the yarn is subjected to nonuniform stretching or shrinkage thereby lowering its yarn quality.

And it is preferred that this tube extend over almost the whole of the distance through which the yarn passes through the flow, the reason being that, if the tube is rnade short and the liquid discharged, the liquid would not behave with a forced uniform motion due to the tubular diameter but would gradually increase its speed due to gravitational acceleration, resulting in stretching the yarn by the liquid flow. The stretching of such an incompuetely coagulated yarn would not only result in impairing the yarn quality but also in disturbing the state of spinning.

After leaving the tube, preferably immediately after leaving the tube, the yarn which has been separated from the coagulating liquid is Wound up on the first rotating member that rotates at a peripheral speed of 150-300 m./min., after which it is stretched between the first rotating member and the second rotating member. If desired, a still another rotating member may be provided besides the first and second rotating members. While normally the stretching performed is about 20-40%, if necessary, it may exceed 40%.

As the foregoing first and second rotating members, the use of reels are preferred. Furthermore, the yarn that has come off the second rotating member is preferably Wound up on a bobbin.

To further illustrate the present invention, the following examples will be given.

EXAMPLE 1 After having manufactured the sodium cellulose Xanthate from ordinary rayon pulp by conventional procedures, it was dissolved with diluted caustic soda thereby obtaining viscose. This viscose contained in 1 liter thereof 92 grams of cellulose and 54 grams of caustic soda, and its Hottenroth number was 11.5. Employing a coagulating bath whose temperature was 48 C. and which contained g./l. of sulfuric acid, 280 g./l. of sodium sulfate and 20 g./l. of zinc sulfate, a yarn of 30 total deniers and 15 filaments was spun. The tube used was 48 cm. in length, the diameter at the opening flaring to an inside diameter of 10 mm. with the rest of the tube having an inside diameter of 4 mm.

The tube was disposed substantially perpendicularly and in a position 10 mm. from the spinneret and 10 mm. away from the horizontal line passing through the center of the reel (the immersion length becomes 50 cm.). In this instance, the tube was made to about coincide with the tangent line to the reel at the point where the yarn is wound up on the reel. The regeneration value of the sodium cellulose xanthate in the yarn was 13.2-15.1% when it was being wound up on the first rotating member. The state of spinning and the ratio of fluify spool when various changes were made in the periphenal speed of the first rotating member, the spinning speed and the draft are shown in Table I.

Table I Peripheral Ratio of Speed of First Spinning Stretching Draft Stetepf Flufiy Rotating Speed Ratio (D) V+200 D Spinning Spools Member (V (rm/min.) (Percent) (Percent) mJmin.)

The state of spinning is indicated by the number of 15 bath the regeneration Value of the yarn was changed and breaks per spindle occurring in the yarn within a 24-hour period, while the ratio of flutfy spools indicates the percentage of the fluffy spools of spun yarn spools.

When spinning was carried out under the conditions in which the peripheral speed of the first rotating member was 239 m./min., the spinning speed, 300 m./min. and the draft, 0.72, as shown in Table I, and a hook was disa 75 de-33 filament yarn was spun.

In this instance, the tube which had an inside diameter of 6 mm. was so disposed that it inclined 23 to the perpendicular and so that the yarn would flow down in the 20 direction tangent to the upper side of the first rotating member.

The properties of the so obtained product are as shown in Table III, below.

"Measured at the time the yarn is being wound up on the first rotating member.

posed between the tube and the first rotating member whereby the yarn was spun by being caused to change its direction at an angle of about 135 C., the results obtained thereby are shown as No. 1 in Table II; and the results obtained by using a tube with an inside diameter of 8 mm. in performing the spinning are shown as No. 2 in the same table.

Table 11 Method of No. 1 No. 2

Table 1 Method Method State of Spinning 0.13 l 7.20 11.4 Ratio of Fluffy Spools percent 1.13 l 100 100 EXAMPLE 2 Viscose was prepared employing the same procedures as in Example 1. In this instance, the concentration of caustic soda in the viscose was 59 g./1. Spinning was per formed with a draft of 0.83 and a spinning speed of 280 55 As apparent from Table III, in case of that in which the immersion length is 15 cm. and whose regeneration value is very low, slight fluff occurs as a result of the force to which the yarn is subjected when it is being removed from the liquid. On the other hand, when the regeneration value exceeds 20%, the elongation of the yarn obtained decreases due to the resistance of the liquid in the tube.

EXAMPLE 3 Sodium cellulose xanthate was prepared by the same procedures as described hereinbefore and then dissolved in dilute NaOH. With the cellulose concentration in the viscose being 92.0 g./l. and with the respective instances in which the NaOH concentrations were 54 g./l. and 66 g./l. spinning was carried out varying in many ways the concentrations of H 50 and that of N1a SO +ZnSO (salts concentration). The sectional configuration of the yarn and the state of spinning that resulted thereby are shown in Table IV.

The yarn spun was 50 (16/18 fils. The draft was 0.94, and the tube having an inside diameter of 6.5 mm. was disposed at an inclination 30 from the perpendicular. The spinning speed was 280 m./min., with the stretching ratio being 32%.

Table IV Caustic Soda Sulfuric Acid Salts Cone. of Sulfuric Acid Salts Cone] cone. of Cone. of Coagulating Cone/Caustic Sulfuric Yarn Section State of Viscose (g./l.) Ooagulating Bath (g./l.) Soda Cone. Acid Cone. Spinning Bath (g./l.)

180 1. 83 1. 89 Very flat. 0.38 230 2. 40 1. 84 Considerable 0. 17

unevenness. 125 280 2. 40 2. 24 Almost circular 0. 06

and substantially perfect. 120 270 l. 79 2. 25 Very flat. 0. 25 270 2. 20 1. 86 Unevenness 0. 13

excessive. 145 370 2.20 2. 55 Almost circular and substan- O. 03 tially perfect.

Having thus described the nature of the invention, What is claimed is:

1. In the tubular spinning of fine viscose yarn of less than 75 deniers which comprises extruding viscose through a spinneret into a coagulating liquid thereby forming continuous filament yarn, passing said yarn through a tube together with the coagulating liquid, discharging said yarn from said tube together with the coagulating liquid and Winding up said yarn on a first rotating member followed by stretching said yarn, the method characterized in that the viscose is extruded into the coagulating liquid in such a manner that the draft D satisfies with respect to the peripheral speed V m./min. \of a first rotating member the condition V+200D 410, Ithat said tube whose diameter throughout its entire length is substantially the same as an inside diameter of 3-7 mm., that said yarn and coagulating liquid are passed through the tube at substantially the same speed, that the regeneration value of the yarn at the time of its being Wound up on the first rotating member is between 8 and 20%, and that said first rotating member is disposed tangentially to the line of the exit flow of the coagulating liquid out of the tube and has a peripheral speed V of 150-300 m./min.

2. The method according to claim 1 in which the sulfuric acid concentration (g./l.) in said coagulating liquid is 1.7-2.6 times the total alkali concentration (g./l.) in the viscose, and the concentration of salts (g./l.) in said coagulating liquid is 1.8-2.7 times said sulfuric acid concentration.

,3. The method according to claim 2 in which the sulfuric acid concentration (g./l.) in said coagulating liquid is 2.0-2.3 times the total alkali concentration (g./l.) in the viscose, and the concentration of salts in said coagulating liquid is 2.1-2.4 times said sulfuric acid concentration.

4. The method according to claim 1 in which said tube extends substantially over the whole of the yarn immersion zone.

5. The method according to claim 1 in which said tube is disposed such that it inclines -90 degrees to the horizontal plane.

6. The method according to claim 1 characterized in that a second rotating member is provided subsequent to said first rotating member and said yarn is stretched 20-40% between said first and second rotating members.

7. The method according to claim 6 in which reels are used as said first and second rotating members.

8. The method according to claim 7 characterized in that the yarn leaving said second rotating member is Wound up on a bobbin.

References Cited by the Examiner UNITED STATES PATENTS 2,440,057 4/1948 Millhiser 18-54 2,511,699 6/1950 Drisch et al. 264-188 3,084,021 4/1963 Morimoto 264-197 ALEXANDER H. BRODMERKEL, Primary Examiner.

WILLIAM J. STEPHENSON, Examiner.

Claims (1)

1. IN THE TUBULAR SPINNING OF FINE VISCOSE YARN OF LESS THAN 75 DENIERS WHICH COMPRISES EXTRUDING VISCOSE THROUGH A SPINNERET INTO A COAGULATING LIQUID THEREBY FORMING CONTINUOUS FILAMENT YARN, PASSING SAID YARN THROUGH A TUBE TOGETHER WITH THE COAGULATING LIQUID, DISCHARGING SAID YARN FROM SAID TUBE TOGETHER WITH THE COAGULATING LIQUID AND WINDING UP SAID YARN ON A FIRST ROTATING MEMBER FOLLOWED BY STRETCHING SAID YARN, THE METHOD CHARACTERIZED IN THAT THE VISCOSE IS EXTRUDED INTO THE COAGULATING LIQUID IS SUCH A MANNER THAT THE DRAFT D SATISFIES WITH RESPECT TO THE PERIPHERAL SPEED V M./MIN. OF A FIRST ROTATING MEMBER THE CONDITION V+200D<410, THAT SAID TUBE WHOSE DIAMETER THROUGHOUT ITS ENTIRE LENGTH IS SUBSTANTIALLY THE SAME AS AN INSIDE DIAMETER OF 3-7 MM., THAT SAID YARN AND COAGULATING LIQUIED ARE PASSED THROUGH THE TUBE AT SUBSTANTIALLY THE SAME SPEED, THAT THE REGENERATION VALUE OF THE YARN AT THE TIME OF ITS BEING WOUND UP ON THE FIRST ROTATING MEMBER IS BETWEEN 8 AND 20%, AND THAT SAID FIRST ROTATING MEMBER IS DISPOSED TANGENTIALLY TO THE LINE OF THE EXIT FLOW OF THE COAGULATING LIQUID OUT OF THE TUBE AND HAS A PERIPHERAL SPEED V OF 150-300 M./MIN.

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