US2077141A - Method and apparatus for spinning rayon - Google Patents

Description

April] 1937- J. BRUGGEMAN 2,077,141

METHOD AND APPARATUS FOR SPINNING RAYON Filed Aug. 19, 1933 4 Sheets-Sheet l IIIII'I'IHH In INVENTOR ATTORNEY April 13, 1937. J BRUGGEMAN 2,077,141

A METHOD AND APPARATUS FOR SPINNING RAYON Filed Aug. 19, 1935 4 Sheets-Sheet 2 Spinning 727m? Hours ATTORNEY April 13, 1937. J BRUGGEMAN 2,077,141

METHOD AND APPARATUS FOR SPINNING RAYON Filed Aug. 19, 1935 4 Sheets-Sheet 3 1.0 1.5 2 o 5}: 7 677 9 Time- /-/0 ans gw/wm/am ATTORNEY April 3, 1937. J. BRUGGEMAN 2,077,141

METHOD AND APPARATUS FOR SPINNING RAYON Filed Aug. 19, 1953 4 Sheets-Sheet 4 Spinniny Time -/70ur5 gm/ fiwggm M215 WMMM ATTORNEY Patented Apr. 13, 1937 UNITED STATES METHOD AND APPARATUS FOR SPINNING RAYON Jean Bruggeman, Alost, Belgium, assignor, by

mesne assignments, to Skenandoa Rayon Corporation, Utica, N. Y., a corporation of Delaware ' Application August 19, 1933, Serial No. 685,797

12 Claims.

This invention relates to a method of spinning filaments, threads, straws or the like. More particularly, it relates to a method for the preparation by the bucket process of yarn that hasimproved uniform aflinity for dyestuffs.

One of the most commonly used processes of producing artificial thread is known as the bucket process. According to this process, the thread, after being spun, is drawn by a constant speed drawing device from the spinneret and is collected in a rotating bucket to form a cake of thread of substantial thickness. Due to the fact that the formation of a single cake may take several hours, depending on the denier of the thread being spun, the thread, as it is drawn into the bucket, since the centrifugal force exerted thereon becomes less and less, is subjected to a gradually decreasing tension. Furthermore, the difierent layers of the cake are subjected to a varying time of contact of the adhering bath liquor during the entire duration of spinning.

When the common and usual spinning conditions are employed in the process just described, the result is a cake of thread which has a nonuniform afilnity for dyestuifs. The last portion of the thread which enters the bucket, and which comprises the inner layer of the cake, dyes decidedly deeper than the thread constituting the outer layers of the cake. Also, the yarn on the inside of the cake is invariably heavier or of higher denier than the yarn which constitutes the outer layers of the cake. If the cake of yarn is washed and dried as such, further non-uniformlty results, even though the yarn is finally skeined and purified, i. e. desulphured and bleached in the form of a skein.

I have found that by compensating for the variations inherent in the formation of a bucket cake of artificial silk, such as produced from iris-'- cose, for example, by progressively increasing the tension on the thread between the bath and the final draw-ofi wheel, I can produce a cake of yarn in which the thread has improved uniform aflinity for dyestufis even with direct dyes.

It is, therefore, an object of this invention to provide a. method for the preparation of artificial filaments, threads, straws, or the like by the bucket process, wherein the yarn constituting the cake has a decidedly improved uniform aflinity for dyestuffs even with direct dyes.

Another object of this invention is to provide a method of producing artificial filaments, threads, straws, etc. by the bucket process, wherein the tension of the thread delivered to the final draw-off wheel is progressively changed.-

Other objects will become apparent from the following description, appended claims and accompanying drawings illustrating several apparatus which may be utilized in carrying out the method and wherein:

Figure 1 is a diagrammatic front elevation partly in section of one form of apparatus designed to carry out one form of the instant invention.

Figure 2 is a side elevation of the draw-off roller shown in Figure 1. A

Figure 3 is a modified form of the apparatus shown in Figure l.

Figure 4 is a side elevation of the roller illustrated in Figure 3,

Figure 5 is a diagrammatic front elevation partly in section of one of the preferred forms of apparatus for carrying out the method.

Figure 6 is a bottom view of the feed wheels il-- lustrated in Figure 5.

Figure '7 is a diagrammatic front elevation partly in section of another preferred form of an apparatus for carrying out the instant invention.

Figure 8 is a bottom view of the feed wheels shown in Figure 7.

Figures 9, 10 and 11 are graphs showing the change in peripheral speed of the first roller, the second roller and both the first and second r011- ers, respectively.

In accordance with the principles of this invention, a viscose solution is extruded into a spinning bath. The thread is drawn through the bath for the required distance, then over a drawing device, more fully explained hereafter, and

is finally directed to a rotating bucket where the thread is collected in the form of a cake.

In order to compensate for the decreasing centrifugal force of the bucket and the variable time of contact of the thread with the adhering coagulating bath, the instant invention contemplates progressively changing the tension of thethread delivered to the bucket. This may be accomplished by an apparatus using a single feed or draw-ofi wheel, even though the preferred embodiment contemplates two draw-oil. or feed wheels.

When a single draw-01f wheel is used, thiscompensation may be secured by progressively increasing the peripheral speed of the wheel during the process. The increase in speed may be secured by driving the feed wheel through a variable speed transmission. Alternately, the single wheel may .be in the form of a truncated cone, and in this embodiment the thread is slowly and progressively advanced along the tapered wheel toward the end having the larger diameter, thereby increasing the thread speed.

In the preferred form of the invention, the double feed wheel spinning process is utilized. According to this procedure, the thread is caused to pass successively around a positively driven feed wheel and then around a second positively driven feed wheel having a peripheral speed greater than that of the first wheel, whereby a stretch is imparted to the thread. By changing ther lative peripheral speeds of these wheels so thatthe stretch of the thread is progressively increased, the compensating effect maybe secured. In this preferred embodiment of the invention, the increased stretch can be secured by decreasing the speed of the first wheel, by increasing the speed of the second wheel or by simultaneously changing the speed of both wheels.

Referring now to the drawings, and particularly to Figures 1 and 2, the reference numeral I designates an artificial thread formed by the viscose process, and which has been drawn through the spinning bath (not shown) for the desired bath travel by the drawing wheel' 2, over which the thread I passes prior to passing into the rotating bucket 3. The drawing wheel 2 is positively driven and of the type commonly used. As the spinning process continues, the peripheral speed of the wheel 2 is progressively increased in any well-known manner, such as by a variable speed drive, whereby the compensating effects are secured.

The following specific example illustrates one embodiment of this invention utilizing a single feed wheel, such as illustrated in Figures 1 and 2:

Example I-Viscose prepared in the usual manner so as to have a viscosity of about 4,000 centipoises, a cellulose content of 7%, and a caustic soda content of 6%, and ripened to a sodium chloride index of 4 (see Reinthaler and Rowe, Artificial Silk, 1928, page 68), is spun through a 40 hole spinneret into the following coagulating bath which is heated to 45 C:

The pump is set to form a thread having an ultimate denier of 150, or under this specific set of conditions the pump is set to deliver 11.7 grams of viscose per minute. The thread I is delivered from the feed wheel 2 to the bucket 3 rotating at 6,000 R. P. M. Q

At the start of the spin the peripheral speed of the feed wheel I is about 63% meters per minute. Gradually and uniformly throughout the spin the speed of the wheel I is increased 3.6% or until at the end of 6 hours, the end of the spin, the peripheral speed thereof is about 65% meters per minute. The cake is doffed from the bucket, is wrapped in cheesecloth, is washed with soft water by the usual drip process and is then dried.

The dried cake is reeled into skeins which are processed in the usual well-known manner to effect a desulphuring and bleaching of the yarn. The yarn comprising these skeins dyes uniformly according to the test set forth hereinafter.

Instead of using a feed wheel of the construction and design illustrated in Figures 1 and 2, a feed wheel, frustro-conical in shape, i. e. one having a tapered peripheral surface, may be employed and such an arrangement is illustrated in Figures 3 and 4.

It is to be understood that in the forms illustrated in Figures 1 and 3, the thread contacts with the feed wheel so that there is no slippage.

Referring now to Figures 3 and 4, the thread I, after it has been drawn through the spinning bath for the requisite distance, is withdrawn therefrom and caused to pass around the frustro-conical wheel 4 and thence collected in the bucket 3. At the beginning of the spin, the thread passes over the wheel 4 near its smallest diameter, such as designated by the reference numeral 5. As the spinning operation continues, the thread is gradually and progressively advanced over the tapered wheel to the end having the larger diameter, such as designated by the reference numeral 6. The advancement of the thread on the tapered wheel 4 may be secured in any well-known manner. For example, it may be secured by means of a guide I fixedly mounted on a shaft 8 which is rotatably mounted and caused to revolve slowly during the course of the process. As the shaft 8 rotates in a clockwise direction, the guide I causes the thread to advance along the periphery of the frustro-conical wheel 4 toward the end having the larger diameter. It is obvious that other suitable means for advancing the thread along the conical wheel may be utilized.

The preferred embodiment of this invention contemplates the use of the double feed wheel spinning process, wherein a stretch is imposed on the thread between two wheels.

Referring now to Figures 5 and 6, the thread I, after traveling throughthe spinning bath for the necessary distance, is withdrawn and caused to pass around the wheel 9, then around a wheel Ill and finally to the bucket 3. The wheels 9 and III are positively driven and of such diameters and/or so operated that the wheel ID has a larger peripheral speed than the wheel 9. As a consequence, the thread between said wheels is stretched. In order to avoid and prevent the thread from riding on itself, suitable guides may be provided.

In the arrangement described immediately preceding, the compensating effects may be secured by decreasing the. speed of the wheel 9 or by increasing the speed of the wheel III or by simultaneously decreasing the speed of the wheel 9 and increasing the speed of the wheel I0.

when the wheels 9 and I are cylindrical in shape, as shown in Figures and 6, the increase and/or decrease of the peripheral speed may be accomplished by driving each of said wheels through the medium of a variable speed transmission. Instead of using variable speed transmissions, the same effect may be secured by employing tapered feed wheels.

The wheel 10 may be frustro-conical in shape, similar to that of wheel 4, and. may be driven at the same or a higher R. P. M. than the wheel 9. During the process, the thread is caused to gradually and progressively advance on the tapered peripheral surface of the wheel toward the end having the larger diameter, with the consequence that the desired results are secured. The same results can be secured by making the wheel 9 frustro-conical in shape and, during the course of the process, causing the thread to gradually advance along the tapered surface toward the end having the smaller diameter. Obviously, both wheels 9 and I Il may be made frustro-conical when the speed of the thread on both wheels is desired to be changed simultaneously. Means similar to l and 8 described in connection with Figures 3 and 4 may be utilized Figures '7 and 8 disclose the most preferred.

form of apparatus which is used for carrying out the'instant process. In this embodiment the thread I, after it has been drawn from the spinning bath, passes around the wheel l3, then around a guide, such as a freely mounted frustroconical roller l1, cooperating with the wheel l3 for the purpose of preventing the thread from riding on itself as it passes around said wheel. After the thread leaves the wheel l8, it passes around the wheel l5, then around a guide l6 similar to the guide ll. Finally, the thread,

after it leaves the wheel [5, is collected into the stantially cylindrical in shape. Hence, during the process, the tension is progressively changed.

It is to be understood that the wheels l3 and I5 may both be of the same diameter. In such an arrangement the tension is progressively changed by; increasing and/or decreasing the peripheral speeds through variable speed transmissions. Likewise, the wheel 13 may be tapered,

or both the Wheels l3 and i5 may be tapered as described above, in connection with the wheels 9 and I0.

It is to be understood that the draw-off wheels described as cylindrical have a slight taper because of the necessary draft in the casting thereof.

In-order to more fully explain the preferred embodiments of this invention, the following specific embodiments are set forth:

Example II-Slowing down the first wheel Cellulose xanthate prepared in the customary manner from wood pulp is dissolved in aqueous caustic soda to form a solution containing 6.4% NaOH and 7.4% cellulose. The viscosity of this viscose solution is about 2,000 centipoises. The

viscose is ready for spinning when it is ripened tothrough into acoagulating bath heated to 45 C. and having the following composition:

Grams per liter Sulphuric acid 115 to 120 Sodium sulphate, 225 to 230 Zinc sulphate 8 to 9 The thread is led through the bath a distance of 18 cm. and then around the drawing wheel located above the bath revolving at a. peripheral the conditions set forth, the final denier of the thread will be approximately 200.

At the start of the spin, the thread is stretched between the two wheels 20.5%. As the spinning continues, this stretch is increased by slowing down the first wheel according to the curve shown in Figure 9. At the end of 3 hours, at which time the spinning isstopped, the stretch has been increased to 31.7% by. slowing down the peripheral speed of the first wheel to about 53.6 meters per minute.

The cake of yarn in the bucket is washed acid free I with soft water at42 C., desulphuredv by treatingthe cake inthe bucket 1% hours with an aqueous solution at C. to C. containing 0.4 to 0.5% sodium carbonate, and thereafter again washed with water at 45 C. The washed cake is wrapped in bolting cloth, whizzed and dried. v.I'he yarn constituting such a cake dyes uniformly throughout.

Similar cakes spun without changing the draw wheel speeds, i. e., a constant stretch between the wheels at 24.6% and at the same rate of deliv-- ery to the bucket (70.6 meters per minute), dye considerably lighteron the outside than on the inside.

Example III-Speeding up the second wheel Viscose is prepared and spun, as is described in Example If, including the same bath composition and other spinning constants except,

thread speed as noted below. In this example,

at the start of the spin, the thread is stretched f 19.8% between two wheels as above described, the first wheel rotating at a constant peripheral speed of. 56.7 meters per minute. The speed of the second wheel is increased throughout the spin, as shown by the curve, Figure 10. At the end of 3 hours, the thread is being stretched 28.4%, at which time the spinning stops. The

cake is processed as is described in Example 11.

The cakev of yarn so produced dyes uniformly throughout.

In the above example, without varying 'the thread speed throughout the spin, stretching the thread 24.5% between two feed wheels and delivering it to the bucket at 70.5 meters per min ute, there will be secured a cake of thread which dyes decidedly lighter on the outside than on the inside. J

Example IVSimultaneously changing the speeds of both wheels both wheels are gradually and simultaneously changed according to the curves shown in Figure 11. At the end of 3 hours, at which time the spinning is stopped, the thread is being stretched 35.6% or the first wheel is rotating at 52.8 meters per minute and the second wheel at 71.6 meters per minute. When processed asset forth in Example II, the yarn thus produced dyes uniformly. I Although Examples 11 to IV given above illustrate the production of 200 denier thread, it is obvious that the same general principles can be applied in the production of yarn of any size or description. For instance, if denier yarn is to be spun, the spinning time can generally be increased to 6 hours and the compensation applied over a longer period of time.

It is well understood by those skilled in the art that even slight changes in various points of the process afiect the properties of the regenerated cellulose yarn and especially the afiinity of the yarn for dyestufis. Therefore, the examples herein given will apply only under the the dyes used, or by making a construction which will minimize dying variations, those skilled in the art can 'minimize natural irregularities in the dyeing properties of rayon. On the contrary, in the sense of this invention a uniformly dyeing yarn is represented by the composite yarn of a number of spun cakes, the extremities of which, when dyed in the form of. the construction with thedye and under the dyeing conditions specified here below, show no difference in dyeing to a ,degree objectionable to those trained in the art. The type of construction specified herein is recognized by those skilled in the art as a procedure having a minimum tendency to obscure dyeing variation.

I specify, therefore, the use of an eight-end Wildman tubing. Four adjacent ends of the tubing shall be from and include the extreme outside 0.10 pound portion of four cakes containing at least 0.50 pound of yarn. The other four ends shall be from and include the extreme inside 0.10 pound portion of the same four cakes.

' This construction is known to the trade as a 4/4 Wildman.

The tubing shall be boiled off (90C. to 100 C.) for 35 minutes in a solution containing per gallon of water 0.3 ounce trisodium phosphate, 0.25 ounce olive oil soap and 0.05 ounce sulphonated castor oil, such as commonly sold under the trade name Monopole Oil". The ratio between the goods and the bath shall be 1 to 30. After thorough rinsing, the tubing shall be dyed to a full shade with Pontamine Sky Blue 63X (color index No. 518). The goods 'shall be entered at a temperature of about 100 F. and the temperature of the bath raised to the boiling point in 30 minutes. After rinsing, the tubing shall be whizzed and dried in the usual manner. p

It should be understood that the uniformity of dyeing claimed for the yarn made by the method herein described is not limited to the use of Pontamine Sky Blue 632! and to the procedure indicated above. Experience has shown that a yarn which dyes uniformly under the above exacting conditions will dye. uniformly under all practical procedures encountered in the trade.v

Since it is obvious that various changes may be madein the specific details hereinbefore described without departing from the nature or spirit of the invention, the invention is not restricted thereto except as set forth in .the appended claims.

I claim:

1. A process for preparing artificial filaments,

threads, straw or the like, which comprises spinthreads, straw or the like,

the thread around I denier and having improved 1 I ning a cell osic solution, drawing the thread from the sp eret by a frustro-conical shaped wheel, progressively advancingthe thread toward the end of the wheel having the larger diameter, and collecting the thread in a rotating bucket.

2. A process of preparing artificial filaments, threads, straw or the like, having substantially uniform dyeing characteristics which comprises spinning a cellulosi solution, drawing the thread from the spinneret by" a driven wheel, passing the thread aroiind a second wheel having a higher peripheral speed than the first wheel whereby the thread is stretched,.progressively increasing the stretch of the thread between said wheels, and collecting the thread in a rotating bucket.

3. A process of preparing artificial filaments, having substantially uniform dyeing characteristics which comprises spinning a cellulosic solution, drawing the thread from the spinneret by a driven wheel, passing a the thread around a second wheel having a higher peripheral speed than the first wheel whereby the thread is stretched, progressively decreasing the speed of the thread on the first wheel, progressively increasing the speed of the thread on the second wheel, and collecting the thread in a rotating bucket.

4. A process of preparing artificial filaments, threads, straw or the like, having substantially uniform dyeing characteristics which comprises spinning a cellulosic solution, drawing the thread fromthe spinneret by a driven wheel, passing a second wheel having a higher peripheral speed than the first wheel whereby the thread is stretched, progressively decreasing the speed of the thread on the first wheel, and collecting the thread in a rotating bucket.

5. A process of preparing artificial filaments, threads, straw or the like, having substantially uniform dyeing characteristics which comprises on the second wheel, and

which comprises extruding a cellulosic solution to form a thread, giving the thread different linear speeds at pro-determined spaced points in its path of travel by passing the same around at least one positively driven godet in advance of a collecting device so as to stretch the thread, and gradually increasing the difference in the linear speeds of the thread at the spaced points upon changing the speeds of the thread at the spaced points, by changing the speed of one godet, whereby objectionable characteristics resulting from contraction in the package are avoided.

7. The process of producing artificial silk thread and the like of substantially uniform dyeing properties which comprises extruding a cellulosic solution to form a thread, giving the thread different linear speeds at pre-determined spaced points in its path of travel by passing the same after formation of the thread over a driven godet at one of the spaced points and then over a second driven godet at another of the spaced points and causing the linear speeds of the thread to be progressively increasing substantially the same as the peripheral speeds of the respective godets with which it contacts so as to stretch the thread, and gradually increasing the difference in the linear speeds of the thread at the spaced points by reducing the speed of the first mentioned godet with the resultant reduction of the speed of withdrawal of the thread as formed, and maintaining the speed of the thread at the second godet substantially constant with the resultant constant speed of the thread at this point, whereby objectionable characteristics resulting from contraction are avoided.

8. A process of manufacturing rayon thread having improved uniformity of dyeing characteristics, which comprises spinning a cellulosic solu"-' tion by ejecting it from a spinneret into a spinning bath, positively drawing the thread from the spinneret and through the bath, collecting the thread in a rotating centrifugal bucket, and progressively increasing the draw-off speed of the thread while maintaining the speed of the rotating bucket substantially constant, whereby decrease in tension upon the thread during its collection in the rotating bucket is compensated by increased tension during a preceding part of the travel of the thread, due to the increased draw-01f speed of the thread.

9. The combination with a rayon spinning machine of the centrifugal type, having a spinneret, a spinning bath, a draw-01f roller, and a rotating collecting bucket which reduces the tension on the yarn on the bucket side of the draw-off roller as the thickness of the yarn cake in- --creases; of means for progressively increasing the tension on the yarn on the spinneret side of the draw-off roller, as the spinning proceeds, by increasing the linear velocity of the draw-off roller at its place of contact with the thread.

10. Apparatus for manufacturing rayon thread by the centrifugal spinning method, comprising the combination with a spinneret, a spinning bath, a rotating centrifugalbucket for collecting the thread, and two driven wheels interposed be-.

tween the spinneret and the collecting bucket for drawing the thread from the spinneret and guiding it to the collecting bucket, of means for progressively changing the relative speeds of the portions of said wheels in contact with the thread in such manner that the tension upon the thread is progressively increased between the wheels during the collection of a cake of thread in the collecting bucket.

11. A process of manufacturing rayon thread is: the centrifugal spinning method, comprising, in combination, the steps of passing a cellulosic solution through a spinneret into a spinning bath, thence passing the thread over two driven wheels and into a rotating collecting bucket, and progressively changing the relative speeds of the portions of said wheels in contact with the thread in such manner that the tension on the thread is progressively increased between the wheels during the collection of a cake of thread in the collecting bucket.

12. Apparatus for manufacturing rayon thread,

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