US3385048A - Multifilament yarn - Google Patents

Description

P. emcosomz ET AL 3,385,048

MULTIFILAMENT YARN May 28, 1968 Original Filed Feb. 8, 1965 INVENTORS PIERO GIACOBONE, DECEASED, BY EMILIA MANFREDINI WIDOW GIACOBONE, ADMINISTRATRIX,

DOMENICO NICITA United States Patent 3,385,048 MULTIFILAMENT YARN Piero Giacobone, deceased, late of Milan, Italy, by

Emilia Manfredini Giacobone, administratrix, Milan, Italy, and Domenico Nicita, Cesano Maderno, Italy, assignors to Snia Viscosa Societa Nazionale Industria Applieazioni Viscosa S.p.A., Milan, Italy, an Italian company Original application Feb. 8, 1963, Ser. No. 257,274, now Patent No. 3,238,590, dated Mar. 8, 1966. Divided and this application Feb. 10, 1966, Ser. No. 526,630

Claims priority, application Italy, Feb. 19, 1962, Patent 700,695 3 Claims. (Cl. 57-140) The present application is a division of application Ser. No. 257,274, filed Feb. 8, 1963, now US. Patent No. 3,238,590 granted Mar. 8, 1966. Application Ser. No. 257,274 is directed to methods and apparatus for producing filaments. The present application is restricted to the filaments produced.

As is known, man-made and synthetic fibers may be produced by extruding a viscous mass through a spinneret consisting of a lforaminous metal plate. The bundle of monofilaments thus extruded can be collected by winding it on a reel or on a rotating spindle. In the former case, all the monofilaments are parallel to the axis of the fiber, whereas in the latter case the monofilaments are helically arranged about the axis of the fiber.

In order that the textile processing operations may be facilitated, such as the formation of a warp, and the weaving or knitting of said fibers, it is customary to impart a twist to said bundles of monofilaments. The known art provides also other processes for imparting to the monofilament bundles a cohesion which sufiices to permit the treatment of said bundles in the weaving operations: for example, it has been suggested subjecting these bundles to the action of gas streams, and more particularly of gas streams endowed with a whirling motion.

The methods adopted heretofore, however, did not prove wholly satisfactory, especially in view of the fact that they produce defective yarns. For example, unevennesses in the dyeing of a woven fabric made with these yarns have been frequently reported.

The primary object of the present invention is the production from man-made and synthetic filaments having no twist or a very slight twist of yarns having a satisfactory cohesion for subsequent weaving.

Another object of the invention is the production from man-made, synthetic filaments of yarns having high tinctorial uniformity.

The degree of cohesion is rated as the number of false knots per meter. The way in which the measurements are taken will be specified hereinafter. It can be said that this number of false knots should be, preferably, from to 50 per meter or more.

According to the present invention, an essentially nontwisted multifilamentary thread is produced from a plurality of single filaments essentially interlaced with one another by the steps of conducting a plurality of single filaments across a gap in a free space in front of a convex surface, and directing a jet of pressurized gaseous medium at the filaments so that said jet impinges on said filaments at essentially right angles to their path of travel and in a direction intersecting said surface, whereby the filaments are deviated towards said surface and contact and interlace with each other as they progress across said 3335,04 Patented May 28, 1968 area between the gas and the thread, whirls having their axes parallel to the feed direction of the thread. Under the influence of the gas stream and in contact with the rod, the individual filaments do not retain their mutual original location parallel to the axis of the thread, but intersect with one another thus forming knot-like clusters. This will confer on the filaments a very satisfactory mutual cohesion without affecting, in the slightest, the evenness of the tinctorial properties of the thread.

The invention can be applied to viscose rayon, acetate rayon, polyamides, polyester and polyurethane filaments and to any other kind of multifilamentary yarns of manmade and synthetic filaments and is adapted to any count of yarn, from 15 deniers to 2100 deniers, preferably from 30 to 840 deniers and to any tenacity, from 1.5 to 15 deniers per monofil-ament.

The invention will now be described with reference to the attached drawing in which:

FIGS. 1 and 2 are views at right angles to one another illustrating a preferred embodiment of apparatus for forming an essentially non-twisted multifilarnentary thread according to the invention.

The apparatus shown consists in a nozzle 10, two thread guides 11 and 12 and in a member 13 with whose surface 16which will 'be called a resting surfacethe sliding thread is in tangential contact. The thread guides 11 and 12 have the shape of rings open towards the nozzle 10 but can also take the form of two-pronged forks or any other form permitting maintaining the thread in a rectilinear posture and well centered in front of the nozzle. The openings of the thread guides depend on the count of the thread and should be carefully selected in order not to interfere with the advancement of the thread.

It is thought that the thread-guides have also the function of hindering any possible vibrational movement of the thread. Such a movement would be detrimental to the correct processing run.

The member 13 can have any suitable shape but it is preferred that it has a resting surface 16 with a curvature so smooth as not to jeopardize the thread. It is preferred that it be convex and cylindrical in shape, with its axis perpendicular to the axis of the thread as well as to the axis of the air stream coming out of the nozzle 10. It is particularly advantageous to form it of a rod of sintered ceramic material having a diameter in the range of 0.5 to 50 turns. and preferably from 1 to 20 rnms. A body with a convex surface having in the zone of contact with the filaments a curvature substantially equal to that of a rod having a diameter as hereinbefore specified, would be substantially equivalent to such a rod. The curvature of said convex surface should therefore show a radius between 0.25 and 25 mm. and preferably between 0.5 and 10 mm.

In any case, the member 13 is placed, away from the nozzle 10, at such a distance from the thread 13 as to come into contact by its surface 16 with the thread at the apex of the deviated path traveled over by the thread when said thread, sliding in the space between the two thread- guides 11 and 12, is laterally thrust by the air jet. The member 13, however, could also be approached to the nozzle 10, thus exerting a deviating action on the path of the thread, and, if so, this path would be formed by two arcs connected by a curve tangent to the surface 16.

The distance between the nozzle and the thread is dependent on the ai jet, the cross-sectional area of the nozzle and the count of the thread and can be varied from 0.5 to 25 mms.; and preferably from 0.6 to 12 mms.

The distance between the tWo-thread-guides seems to have no critical meaning. In practice it is between 1 and 20 cms., preferably between 2 and 6 ems.

The air pressure is varied from 0.5 atmosphere to 12 atmospheres, preferably from 1.05 atm. to 5 im.

The diameter of the nozzle bore may vary from 0.2 to 2.0 mms. and prefaraoly from 0.5 to 2.0 mms. and the rate of fiow of air, which varies according to the crosssectional area of the nozzle and the pressure upstream thereof, varies from 0.68 cu. meters per hour to 3.0 cu. meters per hour, prefarebly from 0.87 cu. meters .per hour to 1.3 cu. meters per hour. All the quantitive limitations set forth are not rigorous, since the invention can be practiced also outside the ranges specified above.

The apparatus described above acts in the following manner: the bundle of substantially parallel filaments is moved downwardly for example in FIG. 1 across the two successive thread guides 11 and 12 which define a rectilinear path parallel to a tangent to the convex surface 16 of the fixed piece 13, and at right angles to the direction of the jet ejected from the nozzle 10. The kinetic energy of the gas jet forces the single filaments of the thread 15 to deviate and come into sliding contact with the convex surface 16.

Since the resting member 13 might deviate the travel of the thread 15 physically and is not struck by the gas jet before this has struck and gone through the thread, the function of said member 13 cannot be easily explained and no theoretical convincing explanation has been found for the effect produced thereby. It has been possible to ascertain, however, that, if this member 13 is removed or is displaced so as to lose any contact with the thread, satisfactory yarns are no longer obtained. The following examples describe the process of the invention without limiting it.

Example 1 A viscose thread consisting of 48 monofilaments in the course of coagulation is drawn by a pair of skew rollers and subsequently collected, at different speeds; on foraminous aluminum bobbins. Between the feed roller and the collecting bobbins the thread has been thrust by an air jet produced by a nozzle having a diameter of 1 mm., a length of 6 mms. and fed by compressed air at a pressure of 3 kgs./sq. cm. (relative pressure). The axis of the thread (this is moved at a speed of 83 meters per min.) was placed at a distance of 22 mms. from the nozzle opening. At the side of the thread away from the nozzle, there was placed a cylindrical body with its axis perpendicular to the axis of the thread, and this body consisted of a rod of sintered ceramic material, having a diameter of 4 mms.

The thread collected on the bobbins, after neutralization, desulfurization, bleaching and drying had an appearance similar to that of a thread obtained under the same conditions but without treatment with the air jet. By placing threads, obtained without and with the use of the air jet, between two fixed points and introducing a needle between the monofilaments it could be noted that in the untreated thread the needle was able to slide even a meter long without any hindrance, whereas the thread treated with the air jet arrested the needle after a travel not longer than:

4-8 crns. when the speed of the collecting bobbin was by 4% lower than that of the skew rollers;

2-5 cms. when the speed of the collecting bobbin was by 7% lower than that of the skew rollers, and

0.5-3 ems. when the speed of the collecting bobbin was by 10% lower than that of the skew rollers.

Every point at which the needle was stopped was regarded as a false knot and, consequently, there is, in the several cases, a degree of cohesion which is inversely proportional to the mean distance between two consecutive false knots.

Example 2 A 75 denier acetate rayon thread, formed by 23 parallel monofilaments has been passed, at its exit from the spinning cells, between a nozzle as described in the foregoing and a rod spaced from the nozzle, so as to be thrust by the air jet coming out of the nozzle at a pressure of 5 kgs./sq.cm. The sliding speed of the thread was the one usually adopted for acetate rayon spinning, that is to say: 600 meters per minute, and the thread was fed and collected practically at the same speed. However, in view of the particular stage of the process run in which the operation according to the invention is being effected, it can happen that a certain shrinkage of the thread may take place, so that a difference between the feeding speed and the collecting speed may arise. This difference, at any rate, is not due to the requirements of the invention. This consideration has the value of a general rule. The distance between the thread and the nozzle bore was 5 mms. but this distance could be varied within a relatively wide range. The rod, in the example in point, was formed by a rod of sintered ceramic material having a diameter of 5 mms. approximately.

The tension of the thread past the nozzle was of about 23 grs. The thread, collected on bobbins, showed, when examined as hereinbefore described, a number of falseknots varying from a minimum of 15 to a maximum of 22 per meter run. The appearance of the thread was absolutely normal, no appreciable modification being ascertainable by the unaided eye.

With the thread thus treated there have been prepared cloth beams which, on weaving and sizing, proved fully satisfactory, as compared with cloth beams prepared with the normal production thread twists per meter).

The behavior at the loom of the cloth beams so prepared and the appearance and the hand of the fabrics obtained thereby, both for the twill and tatfetas fabrics, were quite normal and equivalent to those obtained with twisted thread (100 twists per meter).

Example 3 A 60 denier, l8 filament nylon 6 (or rayon 66) thread was drawn on a conventional drawing and twisting frame at a speed of say 450 meters per minute with a draft ratio of say 3.47, with the known method of winding the thread between a slow roller and a fast roller.

Past the fast roller and before the ballon arrester, an apparatus, quite similar to that described in the Example 1, was installed.

The thread collected on a bobbin rotated at 6,000 r.p.m. or more and with a twist of 10-15 twists per meter, was placed on a torsiometer. It can be definitely noted that these twists do not constitute a serious obstacle to the advancement of a thread between the filaments until the needle impinges either clamp of the testing machine. If, conversely, the thread has been treated by the process of the invention, the needle is hindered in its travel between the monofilaments every l.55 cms. so that the twists cannot be displaced towards the clamps as it occurred with the untreated thread.

Example 4 A 100 denier, 28 filament nylon 6 (or nylon 66) thread is drawn with a conventional drawing and winding machine and the thread is wound on a bobbin with its monofilarnents parallel to the axis of the thread.

The draft ratio is the same as in Exarnple 3, but the collecting speed is 600 meters per min.

The treatment of the thread according to the method of Example 3, permits producing a thread which, when checked with the method described, shows a number of false knots ranging between 38 and 45 false knots per meter.

Example 5 A 420 denier, 72 filament nylon 6 (or nylon 66) thread is treated according to the procedure of Example 4.

A thread is obtained, which has from 20 to 52 false knots per meter.

While the invention has been described, then, in connection with several different embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, used, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended laims.

We claim:

1. As an article of manufacture, a multifilamentary thread consisting of a plurality of man-made single filaments in essentially non-twisted relationship and connected to each other along the length of the thread by a plurality of false knots, and made by feeding a bundle of said filaments across a jet of a pressurized gaseous medium impinging on said bundle at essentially right angles thereto, while causing said bundle to move slidingly over an elongate convex stationary surface disposed transversely to the direction of movement of the bundle of filaments and at the opposite side of said bundle from said jet, said surface being of small radius compared to the area of said jet where it impinges on said bundle so that the gaseous medium divides and flows around both sides of said convex surface, said thread comprising filaments deviated with respect to the axis of said thread and superimposed in a plane, extending in the direction of movement of said thread and containing the generatrix of said convex surface, as a result of the resistance of said surface to individual displacement of the filaments by said gaseous medium as the filaments move freely transversely of said jet and on said surface only.

2. An article of manufacture as claimed in claim 1, wherein said filaments deviate essentially uniformly laterally lengthwise of the thread.

3. An article of manufacture as claimed in claim 1, wherein there are from 10 to false-knots per meter.

References Cited UNITED STATES PATENTS 2,985,995 5/1961 Bunting et a1. 57-140 3,083,523 4/1963 Dahlstrom et a1. 57l40 3,125,793 3/1964 Gonsalves 28-1 3,167,847 2/1965 Gonsalves 281 FOREIGN PATENTS 554,150 3/1958 Canada.

JOHN PETRAKES, Primary Examiner.

Claims (1)

1. AS AN ARTICLE OF MANUFACTURE, A MULTIFILAMENTARY THREAD CONSISTING OF A PLURALITY OF MAN-MADE SINGLE FILAMENTS IN ESSENTIALLY NON-TWISTED RELATIONSHIP AND CONNECTED TO EACH OTHER ALONG THE LENGTH OF THE THREAD BY A PLURALITY OF FALSE KNOTS, AND MADE BY FEEDING A BUNDLE OF SAID FILAMENTS ACROSS A JET OF A PRESSURIZED GASEOUS MEDIUM IMPINGING ON SAID BUNDLE AT ESSENTIALLY RIGHT ANGLES THERETO, WHILE CAUSING SAID BUNDLE TO MOVE SLIDINGLY OVER AN ELONGATE CONVEX STATIONARY SURFACE DISPOSED TRANSVERSELY TO THE DIRECTION OF MOVEMENT OF THE BUNDLE OF FILAMENTS AND AT THE OPPOSITE SIDE OF SAID BUNDLE FROM SAID JET, SAID SURFACE BEING OF SMALL RADIUS COMPARED TO THE AREA OF SAID JET WHERE IT IMPINGES ON SAID BUNDLE SO THAT THE GASEOUS MEDIUM DIVIDES AND FLOWS AROUND BOTH SIDES OF SAID CONVEX SURFACE, SAID THREAD COMPRISING FILAMENTS DEVIATED WITH RESPECT TO THE AXIS OF SAID THREAD AND SUPERIMPOSED IN A PLANE, EXTENDING IN THE DIRECTION OF MOVEMENT OF SAID THREAD AND CONTAINING THE GENERATRIX OF SAID CONVEX SURFACE, AS A RESULT OF THE RESISTANCE OF SAID SURFACE TO INDIVIDUAL DISPLACEMENT OF THE FILAMENTS BY SAID GASEOUS MEDIUM AS THE FILAMENTS MOVE FREELY TRANSVERSELY OF SAID JET AND ON SAID SURFACE ONLY.

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