US2292629A - Method for imparting finish to cotton yarn - Google Patents

Description

Aug. 11, 1942. w. H. FURNESS METHOD FOR IMPARTING FINISH T0 COTTON YARN Filed Aug. 1 2, 1939' INVENTOR igaffiua, 2

lilllllllllllllllll- ATTORNEYS v Patented Aug 11, 1942 UNITED STATES PATENT OFFICE-F METHOD FOR numa'rnvc Fmsn 130 COTTON YARN William H. Furness, River-ton, N. J., assignor to Americanllayon Company, Inc., Riverton, N. 1., a corporation of New Jersey Application August 12, 1939, Serial No. 289,i69

8 Claims. (01. 8-123) This invention relates to a method of and apparatus for finishing cotton yarns to impart thereto a luster and finish like that of but superior to mercerization. The invention is useful on plied yarns but may also be employed on single yarns.

The object of the invention is to provide a method and an apparatus whereby cotton yams can be effectively and economically finished with one form of apparatus for carrying out the same are illustrated, Figure 1 being a diagrammatic side elevation of the apparatus; Figure 2 being a fragmentary top plan view of one unit of the apparatus, drawn on an enlarged scale; Figure 3 being a section taken on the line 3-3 of Figure 2; and Figure 4 being an enlarged sectional detail of the invention showing how the yarn is led from the bath F to the bath G to be later described.

In the drawing I have shown a machine for simultaneously treating seven ends, but it is to be understood that the number of ends treated may be varied, for which purpose the width of the apparatus may be increased or the units multiplied.

The ends are drawn through the major portion of the apparatus by such means as the squeeze rolls 7, the yarn being drawn off of cones 8 carried by a creel 9, located at the forward end oi the apparatus. The yarn first passes through a hot caustic soda bath A which, in the apparatus illustrated, is approximately fifteen inches in length with a speed of draw such that any given portion of the yarn remains in the bath for about two seconds. Caustic soda solution is controllably supplied through the pipe I!) from the combined heater and storage tank ll. Overflow from the bath A goes to the filter l2 and is re-circulated to the tank H by means of the pump l3 and pipe II. The caustic soda solution is of mercerizing strength, preferably 300-350 grams per liter, and is kept at boiling temperature and preferably at at least. 105 C. because at that temperature it efiectivelywets the yarn and mercerizes it. The action of the hot caustic soda is at least twofold. It imparts a high luster to ders unnecessary, if desired, the use of high priced wetting agents.

On leaving the bath A, the ends run through a hot water wash bath B, to which hot water is delivered at a rate of about 45 cc. per minute, the water flowing counter to the direction of the passage of. the yarn. Here it is the intention to remove a portion of the caustic soda. The overflow from the bath B thus contains approximately '75 grams of NaOH per liter (on the basis of treating ten ends of 20s/1 yarn) and is sent back to the heating tank ll,helping to compensate for the-water lost from the caustic soda. solution for the bath A by boiling.

Bath B is likewise approximately fifteen inches in length, and it takes about two seconds for the ends to pass therethrough.

The ends now pass through a second hot water wash bath C. Here again it is the intention likewise about fifteen inches in length, so that it takes about two seconds for the. ends to pass therethrough. The reduction of the caustic soda in successive steps is advantageous.

The ends now pass through a third water wash bath D where the washing is quite rapid, hot water being delivered thereto at the rate of about 165 cc. per minute. This bath is intended] to remove any remaining caustic soda from the surface of the thread, leaving behind the caustic soda embodied in the yarn. The concentration of the overflow is so small (about three grams per liter on the basis of ten ends of 20s/ 1 yarn) that recovery is impractical and the solution is discarded. Bath D is likewise counter-flow, and is about fifteen inches in length, and ittakes about two seconds for the ends to pass therethrough.

The ends now travel through air between the bath D and the bath F. The space between the baths D and F is approximately fifteen inches.

During the passage through the air, the excess the finished yarn, even to single yam, and mm preferably not counter-flow, and the solution is given, there is a. slight excess of copper sulphate,

about two per cent. This excess is employed for the reason hereinafter to be pointed out. The solution as prepared thus comprises a copper sulphate-ammonium-caustic soda solution (probably in the form of a temporary compound) and the excess or copper sulphate which is present as tetrammonium copper sulphate in solution having united with some of the excess ammonia.

When the process is in operation, the yarn entering the bath F carries along with it a certain amount of caustic soda. The excess of copper sulphate is suflicient to compensate for the caustic soda thus introduced so that, in operation, the bath is a substantially dynamically balanced one. At suitable intervals the bath is analyzed and suflicient tetrammonium, copper sulphate and free ammonia are added to maintain the proper concentration. It is unnecessary to add any caustic soda to the bath for the reason that caustic soda is being continually brought into the bath with the yarn. From about 25 to liters of the solution is used and is circulated, entering the bath at the end at which the yarn enters. The overflow pipe H is located at the opposite end of the bath and discharges into a. settling tank [5. From the settling tank the solution is pumped back to the tank l6.

In order to prevent the ends from contacting with one another in passing through the bath P.

which would be objectionable as it would cause sticking and fiber breakage, I provide individual channels for the ends. These channels are formed by a series 'of upright plates l1, providing channels open at the top and the bottom.

' The channels'are capillary, i. e., the plates are spaced sufliciently close together that capillary action will carry the solution upwardly above the normal level of the solution in the bath, as shown in figure 3. By this it is ensured that the ends, which enter just above the normal level of the bath. will travel under the surface of the solution instead of upon the surface of the solution. This is of great importance as thereby the ends are uniformly subjected to the action of the solution.

The concentration of the solution is such that, for the time that the ends take in traveling therethrough, the fibers projecting from the yarn'are dissolved, while the caustic soda inside the yarn prevents the solution from penetrating too deeply and at the same time neutralizes 0r compensates for the excess of copper ammonium sulphate in the solution. The body of the Yarn is not dissolved and the formation of a core of regenerated cellulose is thus prevented, when the yarn reaches the acid bath G which succeeds the bath F. In this way, it is possible to produce a yarn which is not stifi but is nevertheless freed from prjecting fibers or fuzz and which in consequence has an improved finish or appearance and also an improved feel or hand. The

yarn leaving the bath is thus composed ahnost entirely of alpha cellulose, because the bath, in addition to removing the fuzz, in large part relesser celluloses resulting from variations in the conditions under which growth occurred. In this connection it is also to be observed that the yarn, as it leaves the bath F and enters the acid bath G, is free of any surface coating of dissolved cellulose. and consists of practically nothing but alpha cellulose. possibly in a softened condition.

When single yarn is being processed, in order to ensure that there shall be no coating of dissolved cellulose on the yarn as it leaves the bath F, I- may bend the plates II in ogee form at a plurality of points, as indicated at IS in Figure 2, so that the ends in traversing the bath will rub gently against the plates, thus stripping or: any coating of dissolved cellulose resulting from the dissolving of the fuzz. This does not impair the yarn because there will always be a slight film of liquid between the yarn and the rubbing surface. The fact that the solution is a relatively dilute one also assists in preventing any coating of dissolved cellulose as, in a dilute solution, the dissolved cellulose has a tendency to disperse or float away. That portion which remains in suspension and is carried into the overflow. settles out in the setting tank IS.

The acid bath is preferably in two boxes, the

I concentration in the first varying usually from uid with the thread leaving the bath F, I prefer to controllably supply acid solution to the bath of the above concentrations at the entrance ends of the boxes, with the overflow at the exit'ends. Should there be an dissolved cellulose on the ends entering the bath, it is regenerated and set, but loosens and drops oil so that the yarn leaving the acid bath is free of any coating of regenerated cellulose.

The ends now enter three counter-flow water washes, H, J, and K. The overflow from bath K enters bath J, and from bath J enters bath H. The overflow from bath H is discarded.

The ends now pass through the squeeze rolls 1 which are preferably provided with an overhead water spray to assist in removal of acid carried by the yarn.

Then there is the final water wash L in which hot water is preferably employed, sufiicient water being used to ensure that the yarn shows no acid reaction to litmus as it enters the dryer M, which is preferably of drying can type, a novel and advantageous drying for my yarn. In passing through the drier, the yarn loses its moisture and dries, under the tension that is created between the squeeze rolls and the spools N. From these spools the yarn is subsequently coned for shipment.

If the various baths be lengthened, it may be desirable to provide additional squeeze rolls at one or more points. These should preferably be synchronized so that the tension in the system,

copper oxide.

The overflow from the bath G may beevaporated in the evaporator l9 until the acid has "been restored to the desired strength. This acid containing the sulphates of copper, ammonium and sodium is returned to the reservoir 20 repeatedly, until the salts crystallize on cooling after evaporation. The salts areseparated from the liquor and dissolved in water and the liquor returned to the bath as before. The excess acid present in the solution of dissolved salts, is neutralizer with caustic soda, and a calculated amount of solid caustic soda is added to the cooled solution to release the ammonia from the ammonium sulphate. A part of the ammonia combines with the copper sulphate to form copper tetrammonium sulphate, and the rest remains in solution as free ammonia. This solution is then cooled while being stirred. The sodium sulphate as NazSO4.10H2O (Glaubers salt) separates in fine crystals and is removed in a hydro-extracton. Any copper solution adhering to the crystals may be dissolved by removing them in hot water and filtering oil? the insoluble The salt is then re-crystallized. This product is salable as such or can be dissolved in water and by means of electric current decomposed into sodium hydroxide and sulphuric acid for selling and for re-use in the system. To the copper tetrammonium sulphate and am-- monla solution which was separated by the first crystallization of sodium sulphate, caustic soda is added to make the solution of the concentrations indicated for the bath F.

The solution from the washes H, J and K is so dilute that only copper can be recovered therefrom. By adjusting this solution to a pH of 5.7 by the addition of caustic soda, the copper separates as basic sulphate and can be dissolved and used in the preparation of the treating solution.

Referring to Figure 4, the end 30 of the tank of the bath F stands high, so that the yarn can freely enter into bath G and under a guide 3|, well removed from the entrance end of bath G.

This application is in part a continuation of my co-pending application Serial No. 105,476, filed October 14, 1936.

I claim:

1. The continuous process of treating and finished cotton yarn which comprises, drawing the yarn through a caustic soda bath of mercerizing strength, then through several successive water baths to remove excess caustic soda but leaving behind the combined caustic soda, then through space to permit drainage o1 excess liquid, when while still moist through a copper sulphate, ammonia, caustic soda solution prepared in substantially the following proportions, coppersulphate 39.31 grams per liter, ammonia 66 grams per liter, caustic soda (NaOH) 12.105 grams per liter, and water to make one liter,

whereof the excess copper compensates for the caustic soda carried into said solution by the yarn then through an acid bath, then throughishing a multiplicity of separate cotton yarn ends .which comprises simultaneously drawing the ends through a caustic soda bath or mercerizing strength, then through successive water baths to remove excess caustic soda but leaving behind the combined caustic soda, then while still moist through a copper sulphate, ammonia, caustic sodasolution prepared in substantially the following proportions, copper sulphate 39.31 grams per liter, ammonia 66 grams per liter, caustic soda (NaOH) 12.105 grams per liter, and water to make one liter, whereof the excess copper compensates for the caustic soda carried into said solution by the yarn, the ends being maintained out of contact with one another in the passage through said solution; then through an acid bath and through water baths to remove the soluble salts and the acid, drying the ends and winding the treated, dried ends on individual holders.

3. The continuous process or treating and finishing a multiplicity of separate cotton yarn ends which comprises simultaneously drawing the ends through a caustic soda bath of mercerizing strength, then through successive water baths to remove excess-caustic soda but leaving behind the combined caustic soda,- then while still moist through a copper sulphate, ammonia, caustic per liter, ammonia 66 grams per liter, caustic soda (NaOH) 12.105 grams per liter, andwater to make one liter, whereof the excess copper compensates for the caustic soda carried into said solution by the yarn, the ends being maintained outof contact with one another in the passage through said solution; then through an acid bath and through water baths to remove the soluble salts and the acid, drying the ends and winding the treated, dried ends on individual holders; all with substantially only that tension produced by drawing the ends through the several chemical treating baths. a

4. The continuous process of treating and finishing a multiplicity of separate cotton yarn ends which comprises simultaneously drawing the ends through a caustic soda bath of mercerizing strength, then through successive water baths to remove excess caustic soda but leaving behind the combined caustic soda, then while still moist through a copper sulphate, ammonia, caustic soda solution-prepared in substantially the fol-.

lowing proportions, copper sulphate 39.31 grams per liter, ammonia 66 grams per liter, caustic soda (NaOH) 12.105 grams per liter, and water to make one liter, whereof the excess copper compensates for the caustic soda carried into said solution by the yarn, the ends being maintained out of contact with one another in the passage through said solution; by causing each of them to travel through a capillary channel; then through an acid bath and through water baths to remove the soluble salts and the acid, drying the ends and winding the treated, dried ends on individual holders.

5. The continuous process of treating and finishing a multiplicity of single cotton yarn ends which comprises the steps of simultaneously drawing the ends through a series of successive baths with substantially only that amount of tension produced by drawing the ends through said baths, the baths in their order being a caustic soda bath of mercerizing strength, a series of water baths to progressively remove excess caustic soda, but leaving behind combined caustic soda, a copper, ammonia, caustic soda bath pre- 4 r n pared in substantially the following proportions; copper sulphate 39.31 grams per liter, ammonia 66 grams per liter, caustic soda (NaOH) 12.105

j caustic soda bath unifiow.

7. The method oi efiectively subjecting yarn ends to a. liquid treatment bath which consists in causing the liquid oi' the bath by capillary action to rise vertically between closely spaced stationary plates to a point above the level of the body of the bath and in drawing theyarn through that portion 01 the liquid which has been raised above the level of the bath, the point oi! ingress oi the yarn being above the level oi the body of the bath but below the level oi! the liquid so raised.

8. The method of eflectively subjecting a mul-. tiplicity of yarn ends to a liquid treatment bath which consists in causing by capillary action the liquid in the bath to rise vertically between closely spaced stationary plates at a plurality of spaced points above the level of the bath and in drawing a yarn end through each such raised portion of liquid, the point of ingress of each end being above the level of the liquid in the bath and below the level of the raised liquid.

WILLIAM H. FURNESS.

Images