US2334325A - Continuous spinning - Google Patents

Description

Nov. 16, 1943. l G. A. M. HElM 2,334,325

N v 16, 1943. G. A. M. HEIM 2,334,325

CONTINU'OUS SPINNING Filed May 1l, 1940 2 Sheets-Sheet 2 mmf/W Patented Nov. 16, 1943 CONTINUOUS SPINNING Gustav A. M. Heim, Velp,

to American Enka Corporation,

Netherlands, assigner Erika, N. C., a

corporation of Delaware Application May 11, 1940, Serial N0. 334,659

In the Netherlands September 19, 1939 4 claims.

The present invention relates to the manufacture of rayon and, more particularly, to a method and apparatus for the production of rayon according to the continuous spinning method.

For a number of years, it has been the practice in the normal commercial production of multi-filament viscose rayon by the wet spinning process to extrude a viscose solution through spinnerets into a precipitating or coagulating bath and immediately thereafter to collect the filaments formed thereby as a package on a :bobbin or in a lcentrifugal bucket. The package of wet thread is then removed from the bobbin or bucket and subjected to the necessary aftertreatments such as washing, desulphurizing, bleaching, drying, twisting and finishing. This same general procedure has beenutilized in the production of other types of rayon.

During each of the after-treating operations, it is customary to mechanically or manually handle the packages of yarn. Such handling is objectionable not only because of the expense involved and the damage to the thread, which is sometimes incurred but also because shrinkage differences are created in the packaged thread thereby for which certain compensations must be made. These various after-treating operations are expensive because not only do they require time and labor but each operation necessitates the use of a separate apparatus. Furthermore, the artificial thread produced by the so-called non-continuous or interrupted type of process is of a non-uniform character and is inferior in certain respects to the thread which is produced by the continuous spinning method.

The disadvantages presentl in the interrupted type of system have been recognized for a long time and the rayon industry has endeavored to overcome them and to achieve more efficient results in a more practical and simplified manner. In this connection, attempts have been made to conduct the entire spinning process continuously and to produce thereby a nished thread that is in condition for immediate fabrication. As a matter of fact, several different types of continuous spinning machines have been developed which do completely process the thread prior to its initial collection. However, the heretofore known continuous spinning machines have not proven entirely satisfactory as the thread, while being produced, is subjected to considerable yfriction and the equipment necessary is cumbersome, complicated and it takes up an excessive amount of space. Additionally,

ci. is-vs) such equipment is relatively expensive for individually treating the threads.

In order to provide a continuous system that is commercially practical, it is necessary to maintain a sufiiciently large production to justify the use of a machine of the continuous spinning type. Normally, however, if a large number of rayon threads, each composed of a multicplicity of laments are extruded and continuously processed on rollers, storage devices and the like, the threads, and therefore the'filaments, being carried in parallel relationship 'cannot be maintained separate, as they become entangled and run together in the'form of a cable. Consequently the individual laments of such threads are not equallyl affected by the processing uids and, therefore, uniform characteristics are not retained in the threads. Moreover, in attempting to separate cable of composite threads it has been found impossible to separate the threads into equal numbers of filaments.

Some of the systems which had been provided for the continuous and simultaneous production of rayon threads involves the use of conveyor belts over which the threads are spread. It was soon determined that by the use of such equipment the threads were improperly'treated from a practical standpoint and the treating liquids caused the entanglement of the threads. In another type of system, it was attempted to maintain the threads separate during the passage thereof along their path of travel by 4means of hook-shaped guiding devices. However, it was found that such guiding hooks acted as friction devices and, therefore, damage of the filaments was effected either by the rupturing thereof or by the imparting of non-uniform characteristics to the thread.

The present invention contemplates the provision of a continuous spinning system for the manufacture of rayon threads wherein a plurality of threads are extruded, and simultaneously and continuously processed While being maintained separate, one from the other, together with provisions for the eD'icient initiation of the operation thereon.

A further object of the invention is the provision of a method of, and system for, the concurrent production of multi-filament threads including the continuous passing of the same through aplurality of treating baths under tension, but without substantial friction.

Addtionallythe present invention has as an object the provision of an apparatus and process by which a plurality of bundles of filaments are continuously propelled side by side through a plurality'of treating baths, stretched to the same extent and subjected to the respective baths in a uniform manner so as to avoid variations between the filaments being treated after the la-f ment bundles have initially been threaded upon the apparatus in a composite bundle. Other objects and advantages of this invention will be apparent from the following detailed description when considered in connection with the accompanying drawings, wherein;

Figure 1 represents a diagrammatic view in elevation of a continuous spinning machine concreasing the peripheral speeds of succeeding rollers. It is usually desirable to stretch the threads from about 49% to 80% in the lrst bath and impart additional stretch in succeeding baths, or at least the threads may be maintained under tension by very small increases in peripheral I speeds of the succeeding rollers.

ing bath 4. Freshly coagulated threads 5 emerging from the spinneretsl are passed over freely :rotatable rollers 6 and directed to a draw-oil? assembly indicated at 1. Q

This draw-oil assembly 'I consists of three driven rollers which are positioned vertically, one above the other. Thus, as the threads 5 are propelled around the rollers, as indicated in Figure 1, substantially no slippage takes place.- The upper and lower rollers of assembly 'l are provided with circumferential grooves 8. The number of these grooves corresponds to the number of threads being spun, each groove thereby accommodating a single thread. These grooves 8 keep the threads separated as they are being propelled therearound. In order to assure complete separation of the threads, the grooves should be spaced apart from 3 to 5 mm. and should be approximately 1% mm. in depth with slightly rounded contours.

After the threads have been-propelled around the rollers of the assembly 1, they are conducted through a series of treating baths arranged within a tank 9, which is divided into a number of compartments I 0. Each of these compartments accommodates an individual treating bath. 'I'he thread is passed in and out of each treating bath a number of timesl by means of a series of driven rollers Il, located above that particular bath, and a corresponding series of freely rotatable rollers l2, which are either partially or completely submerged in the bath. As shown in Figure 1, the thread is propelled from the lowermost roller of the assembly 1 to the rst freely rotatable roller in the series of rollers I2 in the bath and thence, alternately and in sequence, around driven rollers l I and freely rotatable rollers I2. The driven rollers H are provided with grooves corresponding in number, size, and shape to those constructed in the upper-most and lower-most roller of the assembly 1. Y

As the threads are passed through the several treating baths, they are subjected to the treatments required for the particular use to which the threads are to be put. For example, in the manufacture of viscosevrayon, threads may be subjected successively to a treatment with a dilute acid solution, hot water, desulphurizing' bath, cold water, and a finishing agent, etc. The proper amount of stretching may be eiected during the path of travel of the threads by in- After the threads have been given the desired processing treatments, theyvare passed to a drying assembly I3, consisting of a plurality of driven rollers which are heated from the interior by means of any suitable heating medium such as hot water or steam supplied through inlet ducts- Iil and'outlet ducts I5. If it is necessary, one or more of the rollers in the drying assembly I3 may also be provided with circumferential grooves similar to those on the processing and stretching rollers.

Y After the threads have been dried. they are passed through guides IB and I1 rotatably positioned on a twisting machine whereupon they are finally twisted and collected in a form sultable for marketing.

In .initiating the spinning operation, the,

threads are bundled together and carried around the rollers of the draw-oil' assembly and the processing rollers in the form of a cable consisting of a, multiplicity of parallel laments. This cable, after passing through the drying assembly,ls collected on an auxiliary roller I8.

After. the spinning operation has commenced and the threads passed around each of the rollers in the system as a composite bundle, they may be separated by means of a comb device indicated at I9 in Figure 3. 'I'his comb device consists of a number of teeth corresponding to the number of threads being spun and to the number of grooves in each of the rollers. This device may be manually or mechanically operated and acts to separate the threads prior to their contact with the rst roller of the assembly 1. and thereafter it is used in front of each of the succeeding grooved rollers. A' comb device may be employed that is carried Vautomatically by the threads themselves around each of the grooved rollers. After the threads have been separated, each one being positioned in its corresponding grooove, they are then threaded up to their respective twisting spindles 20.

l'Ihe number of processing rollers depend upon the speed ofthe machine, on the total denier, the elementary denier of the finished threads and on the number of treatments required. For example, a Viscose thread of 275 denier with 120 lilaments, is spun at a speed of 60 meters per minute (take-up speed), and eight sets of rollers are employed having a diameter of mm. The axes of the submerged series of rollers are 50 mm. below the surface of the treating liquid.

In the preferred embodiment of the invention, the threads are maintained under tension throughout the manufacturing process. If, however, complete shrinkage is desired, the threads may be caused to pass through a heated zone under no tension in lieu of passing them over drying rollers under tension. If partial shrinkage is desired, the threads may-be dried under tension on heated rollers until the moisture content has decreased to about 40 or 30% and they may then be allowed to dry in warm air with the tension removed.

Various modications may be made in the spinning system without departing from the spirit thereof. For example, instead of submergescasas sprays may be employed for impinging the treating fluid on the said rollers and thereby subjecting the threads passing therearound yto an action similar to Vthat of a bath. It may be desirable to positively drive the series of rollers located within the baths in a manner similar to the seriesof rollers located above the baths. Moreover, the rollers rotating in the v baths may be grooved in order to assure more complete separation of the threads. Instead o employing a driven roller for each of the rollers rotating within the baths, one driven roller may be employed for pairs of rollers rotating within the baths.

Having now described the invention in its preferred embodiment, it is to be understood that,

the scope thereof is to be limited only by the apl pended claims.

What is claimed is:

l. Apparatus for the simultaneous continuous production of a plurality of rayon threads comprising, a spin bath container, a pluralityof spinnerets, a series of pairs of vertically spaced horlzontally disposed parallel thread supporting rollers, each of said rollers being provided with a plurality oi circumferential guide grooves for accommodating simultaneously a plurality of threads, a plurality of treating bath containers each underlying at leastl several of said pairs of rollers, each of the pairs of rollers being so positioned with respect to the respective bath containers that one roller thereof is received within the container, the plurality of spinnerets being adapted to produce simultaneously a number oi threads corresponding to the number of grooves on each roller and being disposed adjacent one another in a line which is at such an angle to a vertical plane in which any one of the axes of said rollers lies that lines drawn from the ends of said line to respective outermost grooves on said rollers are substantially parallel, and the spinningbath container having walls lying substantially parallel with the line of spinnerets and substantialy ccextensive in length therewith, and separate means for collecting each of the threads alter the delivery thereoi from the rollers.

2. The method o producing rayon which cornprises extruding a cellulosic solution to form a plurality of bundles oi filaments, initially directing the bundles of laments together to form a composite bundle, propelling the composite bundle of filaments over a series of rollers'having wide contacting surfaces auch as to accommodate a plurality of the original bundles in parallel spaced relation, thereafter edeoting the progression of the point of combining of the original 4bundles into the composite bundle through the series of rollers thereby to cause the original bundles to pass in parallel relation through the rollers up to a point ci temporary collection, severing each of said bundles adjacent the ternporary collection point and delivering the end of each bundle to a separate collecting device.

3. The method oi producing rayon by the wet spinning process which comprises entruding a cellulosic solution to form a plurality oi bundles oi filaments, conducting each bundle or filaments produced through a coagulating bath, passing each bundle of filaments over a freely rotatable roller, directing the bundles of filaments together to form a composite bundle, propelling the composite bundle around a series of driven rollers having wide contacting surfaces such as to accommodate a plurality ot the separate bundles.

subjecting the composite bundle to treatments while in Contact with said driven rollers, temporarily collecting the composite bundle, thereafter directing the separate bundles as they are passed from the freely rotatable roller toand over the series of driven rollers in their separate form up to the point of temporary collection, severing each of said bundles at the point pf temporary collection, delivering the end oi each bundle to a collecting device continuing the operation and subjecting succeeding portions of each of the bundles to treating liquids in contact with the driven rollers.

'4. The method of producing rayon by the Wet spinning process which comprises extruding a cellulosic solution through a series of spinnerets. conducting each bundle oi illaments produced through a coagulating bath, passing each bundle of filaments over a freely rotatable roller and then combining the bundles to 'orm a composite bundle, directing the composite illament bundle around a series of driven rollers provided for normally handling a plurality ci separate bundles, temporarily collecting the composite bundle. thereafter engaging the spaced individual bundies near the point o passage over the iireely rotatable rollers by a comb spreader bar and propeiling the bar through the series or rollers to a point adjacent the temporary collecting device by the bundles oi filaments, removing the comb spreader bar from the bundles, severing each of the bundles near the point or temporary collection and edecting the independent collection oi the individual bundles.

GUSTAV A. M.

Images