US2898629A - Apparatus for the production of high tenacity viscose rayon yarn - Google Patents

Description

Aug. 11, 1959 B. DE GEE 2,398,629 APPARATUS FOR THE PRODUCTION OF HIGH TENACITY VISCOSE RAYON YARN Filed March 21, 1957 29 F16. l o

{i 27 /3 k I 20 27 4 W 9 Z a a 3 l6 9 2 2 n W I IN VEN TOR. 308 de GEE United States Patent Ofiice 2,898,629 Patented Aug. 11, 1959 APPARATUS FOR THE PRODUCTION OF HIGH TENACITY VISCOSERAYON YARN Bob De Gee, Arnhem,Netherlands, assignor to American Erika Corporation, Enka, N.C., acorporation of Delaware Application March 21, 1957, Serial No. 647,560 Claims priority, application Netherlands April 11, 1956 6. Claims. (Cl. 18-8) The present invention relates in general to the manufacture of rayon and more particularly to an apparatus that can be used efficiently for manufacturing high strength viscose rayon yarn at high spinning speeds.

Extensive research is continually conducted by viscose rayon manufacturers to find methods of improving the physical propertiesof yarn. When rayon'cord is used in tires and other rubber products, the strength and resistance to flex fatigue is most important. To meet this problem, the rayon industry has been able in recent years to supply its customers with yarns of greatly enhanced properties.

In the ordinary production of high tenacity yarn, vis- 2 Hence, a need exists for spinning viscose yarn at an economical speed while using the known spinning techniques of low acid spinning and chemical modification without altering the ordinary spinning apparatus to a tube portion creates a pumping action on the liquid in:

the smaller tube portion. In thisway the yarn may be e initially subjected to the treating liquidiin the spinbath cose is extruded into a bath containing sulfuric acid,

sodium sulfate and zinc sulfate. The freshly coagulated yarn, before it becomes completely regenerated, is stretched between two godets rotating at different speeds while passing through a hot weakly acidic bath."

Recently, it has been discovered in the rayon industry that certain chemicals, referred to generallyin the artas viscose modifiers, alter and retard the coagulation-regeneration process of viscose in a very favorable manner. The modifiers not onlycause a pronounced change in the molecular structure of the regenerated cellulose but also retard the regeneration process.

With the regeneration beingretarded, the yarns remain in a plastic state longer which enables the yarn to be subsequently treated in a variety of ways heretofore not possible, such as imparting an even greater stretchto the yarn. By the use of modifiers, rayon yarn of the extra high tenacity type may be produced.

Many viscose modifiers are known inthe art today and include polyalkoxy glycols or their reaction products with certain amines, alcohols, fatty acids and aromatic acids, certain aliphatic or aromatic monoamines, diamines and polyarnines, certain quaternary ammonium compounds or heterocyclic bases, certain monocarbarnates or dithiocarbamates, and others; i

Also, recent experiments indicate that viscose yarn of even higher tenacity andhigher fatigue'resistance may be obtained by spinning-viscose into a spinbath of relatively low sulfuric acid content of about 4.07.0%.

However, by employing either the low acid,- modifier, or the combination of the two, the yarn may remain in a tender stage for a longer period of time than in ordinary viscose, spinning. And, accordingly the need of protecting the tender yarn for a longer period arises.

With the regeneration process being retarded, the yarn is very sensitive to break and rupture. Also, the spinning speed of the yarn must be greatly reduced if theordinar-y I viscose spinning apparatus is used. In many instances, the reduction of speed is so great that the cost of pro duction increases to such an. extent that the cost of high tenacity viscose yarn may be no longer competitive. 1

Furthermore, the viscose rayon spinning apparatus represents a tremendous financial investment and may not be conveniently altered without incurring a great expense.

. no part of the present invention.

under a minimal tension without adverse liquid turbulence while the yarn in the tube is in a tender stage.

Another apparatus for regenerating freshly spun yarn while traveling through a confined liquid treating tube is disclosed in US. Patent No. 2,440,057. In this patent the liquid is abruptly separated from the yarn. This.

abrupt separation subjects the yarn to considerable transverse force which is highly undesirable when the yarn is in a tender stage.

An object ofthe present invention is to provide a new" and improved tube spinning assembly for the spinning of viscose rayon yarn of enhanced physical properties at a relatively high spinning speed. i

Another object of the present invention is to provide a new and improved tube spinning assembly for removing from the spinbathviscose rayon yarn which has not been completely regenerated andwhich is still sensitive to transverse forces.

Still another object t oaccomplish the above objects without greatly. modifying the ordinary spinning machine employed by the viscose rayon industry. c

These and other objects will become apparent from the following more complete description of the instant inven tion. l

In accordance with thepre sent invention the objects are accomplished by extruding viscose through a spin: neret into a conventional spinning trough containing a coagulationregeneration liquid, directing the yarn and spinbath liquid through a spinning tube mounted adjacent to and concentric with the spinneret, discharging the spin bath liquid and yarn into an inner container of spinbath liquid and thereafter separating the liquid and yarn. The velocity of the liquid moving co-currently with the threadsis diminished practically to a standstill at which point the yarn and liquid are separated. The. direction of yarn travel from the spinneret to the point of separation from spinbath is preferably inclined, upwardly and generally in a straight line. The process maybe carried out while,

using a chemical modifier and spinning conditions which retard the regeneration of the viscose.

Figure l is a diagrammatic view of a section taken.

along the line 1-1 in Figure 2. c v

Figure 2 is a plan view of one spinning point, showing a preferred embodiment of the invention with the tube spinning assembly being angular-1y positioned in a spinning trough. c

, The drawings are given to facilitate a complete understanding of the invention. For this reason the precise structural details of the apparatus are omitted, as forming Although a most important advantage of the present invention lies in the fact that a plurality of spinning assemblies may be used in one elongated conventional spinning trough, for convenience the present invention will .be discussedand illus- H trated while making referencefto o ly One spinning point.

Referring now to the drawing and more particularly to Figure 1, reference numeral 1 represents an elongated spinning. trough which contains coagulating-regenerating liquidfreferred to herein as spinbath. anddesignated generally by. number 2. Within the-trough there is positioned a spinning assembly comprisingran upwardly inclined two-diameter spinning tube 3, adjacent to and concentric with a spinneret 4, said tube 3 extending into an inner spinning tray, designated generally with reference number 5. For the purpose of easily controlling the flowing streamof spinbath in the spinning .tube, the spinning assembly should be arranged so that the spinning tube is upwardly inclined. Also, in this manner the present invention may be conveniently adapted for use in'conventional spinning machines.

A viscose solution is pumped'to and through spinneret 4. 'Theidirection of the flow of viscose is shown by arrow 6; As the viscose is extruded through the spinneret'4, it coagulates. and forms threads 7 which are directed into and through the spinning tube 3.

The spinning tube 3, preferably made from glass, consists of a narrowportion 8 and a wide portion 9 'connected by a frusto-.conical portion 10. Supporting bracket 11, attached to the bottom of the spinning trough 1, holds the tube 3 aligned with and in spaced relation with respect to the face'of the spinneret 4. The tube 3 is snugly held by supporting bracket 11 but is conveniently removabletherefrom. The free end of the wide tube portion 9 passes through an .opening in the wall'12 of tray in a liquid tight manner. Here, the sealing may be affected by means of a washer made from any flexible, resilient, acid resistant material arranged between the tube and the edge of the openingjin'the wall 12 in a known manner and therefore not further indicated in this description. tube and tray is preferred.

Immediately after the viscose is extruded into spinbath 2, the threads 7 are in an extremely tender stage and aremoved with a minimum tension through the narrow tube portion 8 by the spinbath 2 flowing rapidly in a co-current direction with the yarn. Upon entering the wide tube portion 9, the threads are partially re-v generated and are spread out in a manner which enables a more intimate contact of the individual threads with thenow weaker spinbath liquid. In the ,wide portion of the tube the liquid moves at aslower velocity and more tension is required to pull the threads therethrough. However, in this stage the yarn may be subjected to a greater longitudinal tensioning inasmuch as the threads have become regenerated'to a greater degree.

The inner spinning tray 5, supported within trough 1 in any known manner, is an open topvcontainer defined by walls 12, 13, 14 and 15, which extend above the level of the liquid in spinning trough 1. The walls may form an integral part of the trough or may be separate therefrom as shown in Figure 2. v

The interior of tray 5 is divided into upper and lowe compartments by a false bottom 16, which is perforated as at 17 -and which is secured to the walls'of the tray above the tray bottom 18. Discharge opening is provided-in tray bottom '18 for draining the lower compartment. The false bottom 16 is curved in an upward directionto form a wide overflow edge 20 which is parallel toand spaced from wall 13 but sealed to walls'll2,

14 a'nd'15'to provide areservoir 21 for the liquid which has traveled from the spinning trough lthrough tube 3. "Theoverflow edge 20'is in a plane below the top of wall- 13.

Pipe-22 provides a confined passageway between opening19 to its frusto-conical end 23 and fits with a correspondingly constructed outlet opening 24-located on'the b0tt0m'-0fth' spinning trough. In order 'toillustrate this, they tray-5 in-Figure 1 is' shown in'a' somewhat raised position.

However, an elastic connection between the I The-excess spinbath 'liquid in reservoir 21 reaches-thedischarge pipe 22 by flowing over edge" 20 and/or'through the perforations '17. The liquid in discharge pipe 22 returns to a main spinbath supply point to be replenished with fresh spinbath which enters the spinning system throughconduit 25. The bottom 18 together with pipe 22 and the walls 12, 13, 14 and 15 seals tray 5frorn:the spinning trough 1,- except through the opening in Wallj-12fthrough which tube 3 extends.

On an adjustable support 26, affixed to a wall of tray 5, a' pair of 'freelyrotatable threadjguiding rollers27 and 28 is mounted nearer the overflow edge 20 with roller 27 contiguous to the top level of the spinbath in reservoir 21.

During the spinning operation the liquid level in the spinning trough 1 preferably may be maintained slightly higher than the liquid level lH.I6S6IVOll' 21 as shown in Figure 1. This difference in levels assists the flow of they liquid through spinning tube 3. p

The rayon threads 7 after. leaving the tube 3 are directed through the liquid in reservoir 21. By proper location of thread rollers 27 and 28 and inclination of the tube 3, the threads 7 travel through the spinbath liquid entirely in a straight line. Inother words, the individual threads never change their direction before they are withdrawn from .the liquid at which point the stream of spinbath liquid has :substantiallycome to a standstill. A most importantrfeature of the present invention is the absence ofturbulence of the spinbath liquid at the point where the threads are removed.

After wrapping several times around a conventional godet 29, thethreads aredelivered to points (not shown) for further 'aftertreatrnent in -a known manner.

It has further beenfound that the current is most favorablyminimized whenthe width of the tray is about 1.3 times the diameter of the discharge openingof the spinning tube.

A preferred embodiment of the present invention contemplates a. plurality. -of perforations in the false bottom of the inner tray. In this. way the excess liquid leavesthe reservoir through a multitude of passageways whichdeereases .the agitation of the liquid in the tnay to a minimum. A more gradual and uniform carrying off of the spinbath liquid out of'the tray is attained. In this manner the:filaments are exposed to the small est. possible transverse. forces inasmuch as the yarn is guided out of; the. liquid only afterthe, flow of liquid has almost come to a. standstill.

Figure 2 shows the spinning assembly disposed in a diagonal position in the spinbath trough. This positioning maybepreferred in order to arrange the most assemblies in a troughof givenzdimensions. The simplicity of construction of thewspinning .tube .With the tray connectedtathereto enables adapting the usual spinning: machines to q tube-spinning .without radical modifications since a plurality of tubes with. a. corresponding number .of; traysmay.xbe:easily.:placed in the ordinary elongated spinning troughvand removed therefrom.

If) desired, a grate maybef arranged above the overflow edge to preventthreads -from goingthereover when the threads:are first spun-in.-

"Al-though the location-of the guiding rollers is not of utmost importance, it may' berpreferred, asshown in Figure l,-to--locate theguiding; rollers '27 and '28 in a perpendicular position near the overflow edge 28 Where there is the least noticeable-flow of liquid. Furthermore', it'may also-bepreferredto arrange-the first thread guiding roller so that the periphery of the roller is contiguous tothe liquid in order to give better protection to the tender thread.

The parts of the-apparatus" that come in contact with the spinbath are made of material that is chemically resistant to the spinbath, ,such; as lead.

The above improvement has been described with terms t at rare to be construed in their descriptive sense and, not as terms of limitgtion; and it is intended that all equivalents thereof be included within the scope of the appended claims.

What is claimed is:

1. Apparatus for producing viscose rayon yarn comprising a spinning trough containing a spinbath, a spinneret mounted within said trough, a tray positioned within said trough, said tray having walls and a bottom separating the interior thereof from the spinbath in said trough, a curved false bottom mounted in said tray, said false bottom dividing the interior of said tray into upper and lower compartments and providing an overflow edge for draining said upper compartment into said lower compartment, and a treating tube having one end positioned adjacent to and in coaxial alignment with the face of said spinneret and having the opposite end extending into the upper compartment of said tray, said treating tube providing the sole communication for the flow of spinbath from said trough to said tray.

2. Apparatus for producing viscose rayon yarn comprising a spinning trough containing a spinbath, a spinneret mounted within said trough, a tray positioned within said trough, said tray having walls and a bottom separating the interior thereof from the spinbath in said trough, a curved false bottom mounted in said tray, said false bottom dividing the interior of said tray into upper and lower compartments and providing an overflow edge for draining said upper compartment into said lower compartment in order to maintain a level of spinbath in the interior of said tray slightly lower than the level of spinbath in said trough, a treating tube having one end positioned adjacent to and in coaxial alignment with the face of said spinneret and having the opposite end extending into the upper compartment of said tray, said treating tube providing the sole communication for the flow of spinbath from said trough to said tray, and means for discharging spinbath from the lower compartment of said tray to the outside of said trough.

3. Apparatus as set forth in claim 2 wherein said false bottom is provided with a plurality of perforations.

4. Apparatus as set forth in claim 2 wherein the width of said overflow edge is about 1.3 times the diameter of said treating tube.

5. Apparatus as set forth in claim 2 and further comprising guide means positioned substantially at the level of spinbath in said upper compartment for separating thread and spinbath flowing into the upper compartment of said tray.

6. Apparatus: for producing viscose rayon yarn comprising an elongated spinning trough containing a spinbath, a spinneret mounted within said trough, a tray positioned within said trough, said tray having walls and a bottom separating the interior thereof from the spinbath in said trough, a curved and perforated false bottom mounted within said tray, said false bottom dividing the interior of said tray into upper and lower compartments and providing an overflow edge for draining said upper compartment into said lower compartment in order to maintain a level of spinbath in the interior of said tray slightly lower than the level of spinbath in said trough, a two-diameter treating tube having narrow and wide portions joined by a frustoconical portion, the free end of said narrow portion being positioned adjacent to and in coaxial alignment with the face of said spinneret and the free end of the wide portion extending into said compartment, said treating tube providing the sole communication for the flow of spinbath from said trough to said tray, a discharge pipe for draining the lower compartment of said tray through the bottom of said trough, and a threadguide mounted substantially at the level of spinbath in said upper compartment, said spinneret, treating tube and thread guide being positioned one with respect to the other so that thread extruded through said spinneret will travel in a substantially straight line from the face of the spinneret through the middle of the treating tube to the thread guide.

References Cited in the file of this patent UNITED STATES PATENTS 2,467,541 Taylor Apr. 19, 1949 2,690,663 McDermott Oct. 5, 1954 2,789,315 Pistor Apr. 23, 1957

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