US2158415A - Method of producing artificial fibers - Google Patents

Description

May 16, 1939. A. FORMHALS 2,158,415

METHOD OF PRODUCING A RTIFTCIATI FTBFRS Filed July 28, 195? 2 Sheets-Sheet 1 IN VEX TOR.

A TTORNEYS.

May 16, 1939. A. FORMHALS 2,158,415

I METHOD OF PRODUCING ARTIFJCIAL FIBERS Filed July 28, 1937 2 Sheets-Sheet 2 INVENTOR A TTOR;\'EYS.

Patented May 16, 1939 ETE SATES METHOD OF PRODUCING ARTIFICIAL FIBERS Anton Formhals, Mainz, Germany, assignor of forty-five one-hundredths to Richard Schrei-. ber-Gastell, Mainz, Germany Application July 28, 1937, Serial No. 156,168

2 Claims.

The present invention relates to the production of artificial fibers, and more particularly it relates to a process for the production of artificial fibers by passing a stream of spinning solution containing a volatile solvent into a zone of electrical influence between two oppositely charged conductors or electrodes whereby to whip the said stream of solution or cause the same to be rapidly traversed between the electrodes. This whipping 9 or rapid traversing of the stream of spinning solution during the evaporation of the solvent therefrom causes the same to be drawn out into very fine fibers.

It is therefore an object of the present invention to provide a method for spinning of artificial fibers which comprises drawing a continuous stream of spinning solution into fine fibers by passing the same between electrodes bearing high potential electric charges of opposite polarity.

It is another object of this invention to provide a method for the production of artificial fibers by permitting a continuously flowing stream of spinning solution to become partially set, and drawing the partially set stream into fine fibers by passing the same between electrodes bearing high potential electrical charges of opposite polarity.

It is another object of the invention to produce by electrical means an artificial fiber having a decided curl 'or crimpl Other objects of the invention will appear hereinafter.

In order to illustrate and describe the principles of the present invention, reference is made to the accompanying description to be taken in connection with the accompanying illustration, in which:

Figure l is a diagrammatic perspective view illustrating one form of the applicants invention.

Figure 2 is a diagrammatic elevational view showing a second form of the applicants invention.

Figure 3 is a perspective view illustrating a still further form of the invention.

Figure 4 is a perspective view of still another modified form of the invention,

Referring to Figure 1 of the drawings, -reference numeral ll designates a container for a supply of spinning solution. Connected to the supply container l I is a conduit l3 provided with a plurality of spinning nozzles I5, I6, I! and I8. The spinning solution is passed through the conduit l3 and spinning nozzles l5, I6, I! and I8 and permited to flow downwardly between the electrically charged wire l9 and 20. The wires I9 and 20 bear high potential charges of opposite polarity due to their connection with opposite poles for supplying high potential electricity designated by numeral 22. 'Means for producing high potential charges of electricity are well known in the art and it is therefore not necessary to specifically describe or illustrate the same. The conductor wires l9 and 20 may be charged with an alternating high potential current or with a constant direct or fluctuating direct current -w having a voltage of from 25,000 to 100,000 volts.

The wires l9 and 20 are preferably stretched between stationary insulated supporting means 24 and 26. Each of the Wires, l9 and 20, will be surrounded by an electrical field, and as the-l5 streams of spinning solutipns from the nozzles flow downwardly between the wires I9 and 20, they will come within the electrical influence of the field surrounding one of the said wires which will cause the same to be attracted thereto. As the streams of spinning solutions approach one of the wires, for example, the wire which is posiively charged, they will become charged with a positive charge and will then be repelled by the positively charged wire and will then be attracted by the negatively charged wire. As soon as the stream of spinning solution approaches the negatively charged wire, the stream of solution will become charged negatively and will then again be whipped or traversed towards the positively charged wire. This rapid traversing or whipping of the stream .of spinning solution back and forth between the negatively and positively charged wires will cause the stream to be drawn out to very fine filaments which may adhere to the two wires or which will be drawn down to such a fine filament as to be broken by the whipping action and in either case will drop downwardly after it has become substantially completelyset due to loss of volatile solvent therefrom. 40

When it is merely desirable to gather a fiufied. mass of fibers it is only necessary to position a containing means such as the box 28 beneath the wires so that the fibers may drop down therein and be collected in this manner.

When it is desired to produce a fiber having a considerable crimp or curl, it is found desirable to impart a high potential alternating current to the two wires l9 and 20 so that each of the wires will alternately become positively and negatively charged in accordance with the period of the cycle of the alternating current. By operating in this manner, it is found that the stream of solution which is gradually being fed in the form of a fine fiber will not only be whipped between the two wires I9 and 20 but will also be drawn back and forth in accordance with the period of the cycle of the alternating current so as to form small folds or crimps therein. This is illustrated by the fibers formed from nozzles l1 and I8 in Figure 1 of the drawings. Nozzles l5 and IS in Figure 1 of the drawings illustrate the path of the spinning solution stream and resulting fibers when one of the electrode wires is constantly charged with one charge of electricity and the other electrode wire is given a constant charge of opposite polarity.

Referring to Figure 2 of the drawings, the conducting wires 3| and 32 are arranged vertically instead of horizontally as illustrated in Figure 1.

In this case, the wires 3| and 32 are also preferably arranged in a converging relationship from the upper supports 33 and 35 to the lower supports 31 and 39. When the conducting wires are arranged in this manner, it is found that the fine fibers formed will more readily separate from the wires and drop to they collecting belt 4| which moves slowly in the direction of the arrow and permits the building up of a sliver 43 which can be easily collected on a slowly rotating bobbin or the like.

In the modification shown in Figure'3 of the drawings, the conducting electrode wires 41 and 44 are positioned substantially horizontally and are positioned in a converging relationship to each other from the support 5| to the support 53. It'has been found that when the two wires 41 and 44 are positioned in a converging relationship, as above described, the fibers will adhere thereto and automatically travel in the direction of the convergence of the wires as shown by the arrow in Figure 3. The fibers will collect adjacent to the support 53 and as the fibers become substantially completely set due to the evaporation of volatile solvent will drop downwardly onto the belt 55 where the fibers are collected in the form of a sliver 57 which can be slowly wound onto the bobbin 59.

Referring to the embodiment of the invention shown in Figure 4, the conductor electrode wires ceptacle H through the header conduit l3 and extruded from a substantially horizontal row of nozzles. The horizontally positioned wires are vertically spaced from each other and are stretched between vertical insulating supports 65 and 61. The nozzles in this case must be spaced somewhat above a line bisecting the space between the wires so that the stream of spinning solution will come within the zone of influence of the electrical fields surrounding the wires after flowing downwardly a distance from said nozzles. The stream of spinning solution will be whipped up and down due to the alternate attraction and repulsion. The solvent evaporates from the spinning solution as it is whipped up and down resulting in the formation of fine fibers between the electrode wires. A collecting wheel 3 69 is positioned between the wires as shown in streams of solution between the wires.

ferred that the current of air be heated so that the fibers formed in the process will be more quickly dried.

' In all of the modifications as shown in the accompanying drawings and as described above, the spinning jets are electrically neutral, that is to say they bear no charge of electricity. In view of the fact that these spinning jets or nozzles may become electrically charged from one of the conducting wires by travel of the current along the stream of spinning solution, it may be desired to ground the conduits l3 by means of a wire 2| as illustrated in Figure l or wire 13 as shown in Figure 4.

In the preferred embodiment of the invention the spinning solution is extruded from a grounded, neutral spinning jet spaced from the plane within which the electrode wires lie and positioned between the two charged electrode wires so that the oppositely charged electrical fields cause the at least partially set filament to whip rapidly back and. forth between the two electrode wires. This preferred position of the nozzle varies with factors such as the temperature and humidity of the surrounding atmosphere, the concentration of the spinning solution, the electrical potential charged on the two conductors, etc. With such factors substantially constant and with an electrical potential charge of 30,000 to 100,000 volts or more on the conductors, the spinning jet is positioned preferably a distance of at least 12 inches from the plane wherein the two conductors lie. Preferably, the conductors are charged with a high potential, alternating current so thata decided curl is imparted to the resulting filaments or fibers as they are folded back and forth between the conductors. The mass of folded filaments and fibers is collected and associated into a bundle or sliver by any suitable collecting means. The collection of the mass of folded filaments and/or fibers from the two conductors may be carried out in such a. manner as to break or tear the same into smaller staple lengths.

Without wishing to be limited thereto, the following examples will be given as illustrative of the present invention.

Example I A spinning jet having an orifice diameter of 0.0180 inch is placed at a distance of approximately l236 inches from the plane wherein lie two vertically extending conductor wires and is positioned approximately on a perpendicular bisector of the said plane. The two wires are charged oppositely to each other by connection to opposite poles of a source of pulsating direct current of 30,000 to 100,000 volts, or more. From the grounded and neutral spinneret a solution consisting of 150 grams of cellulose acetate, 600 grams of acetone and 300 grams of the monomethyl ether of ethylene glycol is extruded in the form of a filament towards the charged wires. The filament appears to proceed along a curved path until the solvents have partially evaporated and then begins to whip to and fro with increasing intensity andrapidity as the filament enters and reaches the electrical fields of the two wires. This whip action is apparently engendered by virtue of each of the two wires attracting the filament to its proximity until the filament acquires a charge of like sign, whereupon the wire repels the filament back to the oppositely charged wire which exerts an attractive force on the filament. The filament is thus folded alternately back and forth between the two wires and in doing so, is broken to a certain extent into fibers of varying lengths. Upon continued spinning, a mass of fibers builds up and vibrates between the two wires until shrinkage from the drying separates the fibers from the wires and the mass drops by virtue of gravity to the floor. The resulting fibers are lustrous and somewhat curly and have a pleasing hand and a relatively good tenacity. Instead of fiufled staple, the product may be collected substantially as a continuous bundle or sliver of fibers by means of a moving belt or wheel suitably positioned between the two wires.

Example II The procedure of Example I is followed except that the two wires are charged oppositely to each other by connection to opposite poles of a source of 60 cycle, alternating current of 30,000 to 100,000 volts, or more. In whipping back and forth and in subsequent vibration between the wires, the fibers surprisingly acquire a crinkle corresponding roughly in form and intensity to the sine waves and nodes of the alternating current. The crinkle, of course, is modified slightly as the fibers dry and separate from the wires. Except for the more decided crinkle, the fibers are essentially the same as those secured in Example I. The fibers may be collected as a fiufled staple, or may be collected as a substantially continuous bundle or sliver of fibers by means of a moving belt or wheel suitably positioned adjacent the two wires.

- Example III The same arrangement and procedure are repeated as in Example 1, except for the following points. The two oppositely charged conductors extend horizontally and are positioned parallel to each other in a vertical plane. To offset the effect of gravity and to secure the optimum whipping action of the filament between the two conductors, the spinning jet is placed above the perpendicular bisector of the plane wherein the two conductors lie. The fibers are collected continuously on a rotating wheel rim projecting through the plane wherein the two conductors lie and positioned approximately at the electrical midpoint between the two conductors. Collection of the fibers on the rim of the wheel tears the fibers into shorter staple lengths. From the rim of the wheel the fibers are taken ofi in the form of a continuous bundle or sliver by the rubbing action of a leather belt arrangement which moves slowly around the wheel rim and carries the sliver upward into a guide arm from which the sliver is wound into a skein upon a suitable rotating support.

Moreover, the two conductors do not have to be parallel. Instead, the two conductors may be gradually and slightly converged towards each other in such a fashion as to compensate for the progressive shrinkage of the fibers as they dry. This arrangement is particularly advantageous in the production of flufied, crinkled staple by connection of the conductors to a source of high potential, alternating current. The imposition of the crinkle, patterned substantially after the sine waves of the alternating current, is apparently facilitated by the fibers being kept under more severe vibration during their drying period.

In the above examples, for the most part, electrically charged wires of copper or the like have served as conductors or electrodes.v It will, of course, be evident that the wire conductors may with equal advantage be replaced with strips, sheets, shields, plates or the like made of any electrically conducting substance such as copper, silver, iron, etc.

The distance between the oppositely charged conductors should exceed the distance at which sparks would be engendered between them and should be sumciently small so that the partially set filament is alternately attracted and repelled by the electrical field of each conductor.

Barring the effect of gravity as in the case wherein the conductors extend horizontally and lie parallel to each other in a vertical plane, the neutral spinning means is preferably, as in the above examples, positioned in the extension of a plane coinciding with the neutral zone existing between the electrical fields of the oppositely charged conductors. Consequently, the position of the spinning means is adjusted with factors which influence the location of the neutral zone which may or may not be neutral with respect to the ground. Such factors are the electrical potential on each conductor, the size and shape of the conductor, the material from which the conductor is made, etc.

As cited in the above examples, the product of the invention may be collected as fiufled staple, or as a continuous bundle or sliver of fibers. If a fiufied staple is desired the fibers are simply allowed to fall by gravity to the floor or into a container and the accumulated mass of fibers is removed by suction, by a stream of gas or fluid, or by a belt or other mechanical means. The fluifed staple fibers may be converted as desired into a slivers by the usual textile operations. If the direct production of a continuous bundle or sliver of fibers is desired, the fibers as they vibrate between the conductors are mechanically collected on a grounded endless belt or the rim of a wheel or the like. The collecting means is shaped to best adapt it to the path it is to travel and its position with respect to the conductors as heretofore described in the examples.

A current of air or the like may be blown on the filaments issuing from the spinning nozzle to assist in directing the filaments to the conductors and also in promoting a more rapid evaporation of solvent therefrom.

The present invention may also be applied advantageously to the spinning of solutions of cellulose acetate in solvents other than acetone or the monomethyl ether of ethylene glycol. Likewise, solutions of other cellulose esters, for instance cellulose propionate, cellulose acetopropionate, cellulose acetobutyrate, cellulose acetostearate and solutions of cellulose ethers, such as ethyl or benzyl cellulose may also be spun by the procedure of the invention. Generally, solutions of resins such as polymerized alkyl esters of acrylic- It has also been found that the addition of electrolytes such as salts, acids or bases which affect the conductivity of the spinning solution may be added to advantage in causing the fibers to oscillate more energetically, thereby producing more curl in the resulting fibers.

In the present invention the fibers are not formed by precipitation or coagulation induced by electrical means. Rather, the solvent is preferably permitted to evaporate to some extent from the filament in a normal manner so that the filament is in a partially set condition b'ei'ore it is subjected to the whipping action between the conductors which breaks the filament into fiber lengths to a certain extent. As the result of this technique, a fiber of good hand and of relatively good tenacity is secured. In the apparatus of the invention the grounded and neutral spinning jets facilitate continuous spinning since fibers do not tend to gather or form on the jets so much as in other electrical methods of spinning. Moreover, since there is no electrical charge on the jet, any fibers accidentally adhering to the spinning jet may be readily and promptly removed without interrupting spinning. The fibers of the invention, of course, find valuable application in making fabrics therefrom either alone or mixed with cotton or wool. In wool mixtures, the fibers made in accordance with the invention by the use of an alternating current are particularly adaptable since they possess a decided curl and have a handle which corresponds quite closely to that of wool.

It will be obvious that many changes and modifications can be made in the above described apparatus and processes without departure from the nature and spirit of the invention. It is therefore to be understood that the'invention is not to be limited except as set forth in the appended claims.

I claim:

1. A method for the production of artificial fibers which comprises extruding a stream of spinning solution from a neutral spinning jet into a neutral atmosphere a substantial distance to become partially set, then passing the same between spaced, high potential electrically charged electrodes of opposite polarity in which the polarity is periodically alternated, thereby whipping said streamof spinning solution alternately in opposite directions to cause the same to be drawn out into fine fibers and then collecting said fibers in the form of a sliver.

2.,A method according to claim 1 in which the electrodes are positioned substantially horizontally and in a converging relationship, the fibers traveling in the direction of the convergence of the electrodes.

ANTON FORMHAIS.

Images