US3614817A - Method and device for the production of continuous multifilaments having a high degree of cohesion - Google Patents

Method and device for the production of continuous multifilaments having a high degree of cohesion Download PDF

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Publication number
US3614817A
US3614817A US838256A US3614817DA US3614817A US 3614817 A US3614817 A US 3614817A US 838256 A US838256 A US 838256A US 3614817D A US3614817D A US 3614817DA US 3614817 A US3614817 A US 3614817A
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filaments
cohesion
yarn
jet
groove
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US838256A
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Domenico Nicita
Cesano Maderno
Ettore Luzzatto
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SNIA Viscosa SpA
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SNIA Viscosa SpA
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    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
    • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
    • D02J1/08—Interlacing constituent filaments without breakage thereof, e.g. by use of turbulent air streams

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  • This invention relates to an improvement in the methods and devices for the industrial production of the so-called cohered continuous yarns and more particularly of the yarns consisting of a plurality of thin monofilaments of either a man-made or a synthetic material, non-twisted or only limitedly twisted, but cohered to one another, or mutually interlocked or interlinked so as to form a multifilamentary yarn adapted to certain utilizations in the textile field, without any previous twisting treatments.
  • multifilamentary cohered yarns have the principal technical and commercial advantage that they can be produced with methods which are much more rapid and economical than those employing twisting, that is, than the procedures conventionally adopted to obtain a coherent and unitary multifilamentary structure, to the ends of practical use.
  • they remove the drawbacks inherent in the torsion which has been heretofore left in the filaments, said torsion, for example, decreasing the permeability of the filaments to the tinctorial agents.
  • invention is to provide improved methods and means adapted to permit the performance of such cohesionimparting treatments with a great increase in output, that is of the commercial efliciency of the machines used, without prejudicing, and, conversely, exalting the quality and uniformity of the product.
  • FIG. 1 corresponds to FIG. 1 of the already cited U.S. Pat. No. 3,238,590 to whose text reference is made for a better understanding of the background of the present invention. This figure is reported to facilitate a comparison with the prior art, concurrently with FIG. 2, which is a partial showing of the device of FIG. 1, as viewed from the plane and in the direction shown by II-II of FIG. 1.
  • FIGS. 3, 4 and 5 show, in a perspective diagrammatical manner, embodiments of the essential and characteristic component part of the improved device.
  • FIG. 6 shows, partly in side elevation and partly in section taken along the plane VIVI of FIG. 7, a device of the kind shown in FIG. 1, improved according to the invention with the use of a component of the kind shown in FIG. 4.
  • FIG. 7 is a partial view of the improved device of FIG. 6 as viewed in the direction and the plane indicated at VIIVII in FIG. 6.
  • a cohered yarn Fc starting from a bundle of continuous filaments F of a man-made, or preferably synthetic material, non-twisted or twisted only to a negligible extent, is carried out by feeding in the direction XX the bundle of filaments between the two thread guides 10 and 12 which are aligned and spaced apart through an appropriate distance D, while the bundle is subjected to the action of a gas jet issuing from a nozzle 14 and directed in a direction which is perpendicular, or nearly so, relative to the bundle, at a point which is preferably midway of the gap D between said thread guides, so as to urge the filaments towards a convex surface whose generating lines are oriented in a direction which is, preferably, approximately perpendicular both to the path of the filaments between the thread guides 10 and 12, and to the axis of the gas jet.
  • the convex surface in question is the rear portion of an essentially cylindrical component 16.
  • This constructional approach has proven to be advantageous also for the end result, but the particular configuration of the cross-sectional shape of the component 16 has no criticality to the ends of the application of the prior art, inasmuch as it has been found sufiicient to respect the conditions of substantial convexity of the surface against which the filaments are thrust by the areodynamic action of the gas jet and of the fact that the component 16 has such a shape and a volume as to allow the gas jet to flow easily along its sides after having impinged onto the filaments and flown past the filaments bundle.
  • the bundle-forming filaments deflected from their theoretically linear path as defined by a line joining the two thread guides, contact, randomly and temporarily, the convex surface and undergo individual displacements and oscillations in the plane of tangency with the convex surface and also transversally of the theoretical path aforementioned. It is assumed that, due to these individual movements, many straddlings are manifested among the individual filaments such as to give rise to the desired cohesion effect: the latter should be supported to be proportional to the degree of freedom of the movement.
  • the vibratory hypothesis should not take said amplitude into account (it should be a function of the absorbed energy only) but only of the vibration frequency, or of the longitudinal interval between the members whichphysical ly limit the field in which the vibration takes place. It can be added, conversely, that to limit said amplitude, in the sense of limiting the transversal space where the filament bundle can open and the individual filaments are allowed to be individually displaced and to vibrate, should have been a detrimental circumstance to the ends of the cohesion. Conversely, it has been surprisingly ascertained that a drastic and positive limitation in this direction is favourable to the ends of the results of the inV n i n and is a necessary and critical circumstance therefor.
  • the vibratory hypothesis is consistent with the fact that to adopt jets having a higher kinetic energy, i.e. a higher speed when leaving the nozzle, is conducive to an increase in cohesion.
  • the greater kinetic energy should lead to an increase of the vibration amplitude when the frequencies are equal, since the wavelength is limited by the means which physically limit the treatment area.
  • the increase of the amplitude of the vibrations could explain the phenomenon owing to the fact that the undulations having a greater amplitude lead to an increase of the angle between the filaments which are crossed at the knots of these undulations and thus to a more vigorous straddling and crossing between the filaments of the cohered yarn.
  • the improvement thus consists in providing guiding means for the filament bundle, which act over a distance longitudinally not higher than 20 mm. and, consistently and with this condition, in the order of the radius of curvature, or, stated alternatively, of the longitudinal extension of the surface against which the filaments are urged and with which they can be brought into contact by the kinetic energy of the gaseous et.
  • the contrast surface can be conveniently embodied by a cylindrical surface, so as to encourage the flow of the gaseous jet beyond the filament bundle downstream of the treatment area, this surface is preferably embodied by the rear surface of a cylindrical rod or body, a generating line of which intersects, preferably through a right angle, the axis of the gaseous jet and also preferably, through an approximately right angle, the direction of the filaments.
  • the filaments can contact said rear surface under the action of the gaseous jet through an are having a comparatively small width, in the order of 60 (with a Wide approximation), on taking into account the upper limit of the longitudinal distance of the guiding means, as recalled above, and of the advisability, as determined by trial, that the radius of curvature of the cylindrical surface is not too small, the radius is advantageously comprised between 1.5 mm. and 10 mm. These values are also the preferred limiting values for the distance between the guiding means.
  • the size, in the direction of advance of the yarn, of the body which forms that surface, can lie with advantage in the range between 2 and 40 mm., and preferably between 5 and 20 mm., this size being advantageously selected by adopting a criterion of proportionality with the distance between the nozzle and the contrast surface since the spreading of the jet between the nozzle and the area of the treatment, is proportional to that distance.
  • Such a drastic limitation of the values in which the freedom of movement of the filaments is actually restricted, is physically obtained by providing thread guiding means which are structurally associated to the body which provides the contrast surface.
  • Said means can consist of pairs of thread-guide-forming projections, upstream or downstream of the treatment area, or at the start and the end of the portion of the surface on which the gaseous jet impinges and with which the filaments can come into contact.
  • said means are embodied by a groove formed through the body, at least through the length of the portion concerned, the parallel and converging sidewalls of the groove providing, in themselves, the members which limit the freedom of movement of the filaments.
  • the sidewalls can be wholly continuous, or they may contain discontinuities.
  • such a groove may intersect one or more transversal grooves arranged along generating lines of the convex surface of said body, so as to permit the outflow of a portion of the gas of the jet downstream of the treatment area, in a direction which is transversal relatively to the direction of advance of the filaments.
  • a component part 16a which, for simplicity of construction, can be a cylindrical body, has pairs of projections, 20, 21 and 22, 23, respectively, acting as thread guides, placed at a short distance D, and having the twofold task of restricting to said interval the length of the free portion in which the filaments are allowed to vibrate individually, and of limiting the amplitude A of the lateral vibrations and oscillations upstream and/ or downstream of the interval D.
  • FIG. 4 shows an embodiment of such component part, which is extremely simple and advantageous.
  • the cylindrical body 1612 has an annular groove 25 whose width and depth are adapted to limit both the transversal movements of the yarn being treated, and to restrict the length, D, of the interval in which the oscillations are allowed, to the extent which corresponds to the secant of the external surface 16 of the body 16b and tangent to the bottom surface 16" of the groove 25.
  • a body 16c corresponding to that shown in FIG. 4, is completed by a groove 26 in the longitudinal direction, that is, facing the gas jet and intersecting the circular groove 25 in the area where the filaments are being treated.
  • FIGS. 6 and 7 show an embodiment of the improved device, which generally corresponds to that of FIG. 1, but has a cylindrical grooved body 16b of the kind shown in FIG. 4. It should be observed that, in such case, the distance between the thread guides 11) and 12, contributes, within certain limits, towards establishing the treatment conditions, in that the treatment area becomes limited, both in length and width, by the distance D through which the filaments travel in the groove 25 and by the width A of the groove 25, respectively.
  • the thread guides and 12 serve only to ensure that the filament bundle is positioned and maintained in front of the treatment area, i.e. the groove 25.
  • the distance between the thread guides can be, for example, in the range 20 mm. to 30 mm, the filaments engaging the groove only under the action of the gas jet issuing from the nozzle 14.
  • the width and depth of the groove are selected as a function of the overall denier rating of the yarn and the number of the filaments which form same.
  • a cylindrical body 16b having a diameter preferably between 5 mm. and 20 mm. with an annular groove whose depth is preferably comprised between 0.5 mm. and 4 mm. and whose width is between 0.5 mm. and 4 mm.
  • the device is preferably associate to a nozzle 14 having a diameter between 1 mm. and 3 mm. for a cylindrical bore having a length of between 4 mm. and 10 mm., fed by compressed air at a pressure between 1.5 atmospheres and 5 atmospheres.
  • EXAMPLE 1 A yarn having a total denier of 60 and comprising 18 polyamide filaments, of the nylon-6 kind, drawn on a conventional drawing frame at the speed of 450 meters a minute according to the conventional method of transferring the tensioned yarn from a slow roller to a swift roller, the surface speeds of the rollers being determined so as to give a draw ratio of 1 to 3.47.
  • the yarn Immediately downstream of the swift roller, the yarn has been caused to pass through the device.
  • the latter comprised a grooved cylindrical body (of the type of FIG. 4) with its axis perpendicular to the plane of advance of the yarn, defined by the alignment of the inlet and outlet thread guides 10 and 12 (FIGS. 6 and 7), the cylindrical body having an outside diameter of 12 mm. and an annular groove with a depth of 1.5 mm. and a width of 1.5 mm.
  • the yarn was thrust by a jet of compressed air at the relative pressure of 2 atmospheres, issuing from a nozzle 14 having a cylindrical bore of 1 mm. diameter and 6 mm. in length, the axis of the yarn (defined as outlined above by the alignment of the thread guides of an outlet portion) being at a distance of 2 mm. from the opening of the nozzle 14.
  • the thusly treated yarn was checked in order to ascertain the existence, the number and frequency of the false knots by the conventional method of fastening a thread section between two points, introducing a needle between the filaments and displacing the needle longitudinally along the yarn, the false knots being in those spots where the translational movement of the needle became hindered.
  • EXAMPLE 2 A ISO-denier yarn, made up of 32 nylon-6 monofilaments, drawn as described in Example 1 and completely untwisted (filaments parallel to the axis of the yarn) was treated in the device described in Example 1, but wherein the grooved body had a groove with the same depth of 1.5 mm. but a width of 2 mm. to allow for the higher denier and the greater number of filaments.
  • the nozzle was fed with compressed air at a relative pressure of 3.8 atmospheres.
  • the treatment was carried out at an advance speed as high as 3,800 meters a minute, that is more than 8 times that adopted in the tests described in the previous example.
  • the thusly treated yarn when subjected to check for ascertaining the degree of cohesion obtained, exhibited the formation of from 30 to 40 false knots per lineal meter.
  • the present example thus shows that the application of the improvement, the subject of this invention, affords a degree of cohesion in the order of the one obtainable with the prior art conventional devices, but at a speed which is at least 8 times as great, thus under conditions of commercial production which are considerably improved over the prior art.
  • EXAMPLE 3 An acetate yarn, having a denier of 75 and formed by 23 parallel monofilaments has been fed at a speed of 750 meters a minute in front of a cylindrical body of sintered ceramic material having an outside diameter of 18 mm. and annular groove 1 mm. wide and 1.5 mm. deep, under the action of an air jet issuing under a pressure of 2.5 atmospheres through a nozzle of 3 mm. dia. positioned at 5 mm. distance from the cylindrical body. The yarn was collected under a tension in the order of 3-4 gr.
  • the cohesion degree tests established the existence of false knots in a number which varied between a minimum of 25 and a maximum of 40 per lineal meter.
  • the optical inspection showed that the appearance of the yarn was absolutely normal after the treatment and that the unaided eye could not discern virtually any modification, entanglement or others.
  • EXAMPLE 4 A yarn of viscose rayon having a denier of 120 and composed by 48 monofilaments, was produced under the conventional conditions on a continuous spinning machine and collected with no torsion, that is with the monofilaments parallel to each other. The treatment according to the invention was carried out between the drying device and the take-up reel, at the conventional spinning speed in the order of 70 meters a minute.
  • a device of the kind described above was used, but having a nozzle with a diameter of 1.5 mm. fed by compressed air under a relative pressure of 1.8 atmospheres, projected against a cylindrical body having an outside diameter of 5 mm. and an annular groove having 0.7 mm. width and 1 mm. depth. The distance between the yarn and the nozzle bore was 3 mm.
  • the degree of cohesion tests showed the presence of 40 to 50 false knots per lineal meter.
  • the effects of the treatment showed to be only scarecly influenced by variation, even comparatively wide ones, of the size of the cylindrical body and its groove.
  • a certain advisability of adhering to a proportionality ratio between the diameter of the cylindrical body and the advance speed of the yarn was ascertained, and also to a certain proportionality between the width of the groove and the overall denier count and number of filaments of the yarn, to be treated.
  • proportionality ratios are, generally, consistent with the hypotheses expressed hereinabove.
  • the length of the portion where the filaments or monofilaments are constrained and their freedom of movement or vibration is limited is proportional to the diameter of the cylindrical body, that is of the secant chord, of the outer cylindrical surface of the body in correspondence to the grooved area.
  • An improved device for imparting coherence, by the agency of aerodynamical action, to yarns composed of a plurality of continuous filaments united in bundles, with small or no twist comprising means for effecting essentially rectilinear advance of the bundle along a treatment area, means for projecting onto said bundle, in a direction essentially perpendicular to the direction of advance, a gas jet to deviate the filaments from their direction of advance, a body embodying a convex surface opposed to said jet and intersecting the axis of the jet and tangent to a plane perpendicular to the axis of said jet, and means on said body for delimiting the amplitude and length of the transversal oscillations of the individual filaments under the action of the jet and against said surface.
  • An improved device wherein said surface is the bottom of a groove formed in said body and oriented in the direction of advance of the filaments and defining, by its length and width, the length and the amplitude, respectively, of the transversal oscillations of the filaments under the action of the gas jet.
  • a device wherein said body has a second groove which is oriented perpendicularly to the first groove and intersects the latter at right angles in the area intersected by the jet axis.
  • a device having means which delimit the treatment area and have a size between 1.5 mm. and 10 mm. in the direction of advance of the bundle and between 0.5 mm. and 4 mm. in a direction transversal to the former direction.
  • a device wherein the groove has a depth between 0.5 mm. and 4 mm., a width between 0.5 mm. and 4 mm. and the radius of curvature of the bottom wall of the groove is between 1.5 mm. and 10 mm.
  • W 110 A device according to claim 5, wherein the outside diameter of said body is between 5 mm. and 20 mm.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
  • Treatment Of Fiber Materials (AREA)
US838256A 1968-07-12 1969-07-01 Method and device for the production of continuous multifilaments having a high degree of cohesion Expired - Lifetime US3614817A (en)

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IT1892768 1968-07-12

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US (1) US3614817A (pl)
JP (1) JPS4815695B1 (pl)
BE (1) BE736018A (pl)
BR (1) BR6910639D0 (pl)
DE (1) DE1935350C3 (pl)
FR (1) FR2012889A1 (pl)
IE (1) IE33191B1 (pl)
NL (1) NL6910530A (pl)
PL (1) PL80188B1 (pl)
RO (1) RO58377A (pl)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899809A (en) * 1972-12-19 1975-08-19 Zellweger Uster Ag Yarn clamping device
US5146660A (en) * 1990-07-02 1992-09-15 Heberlein Maschinenfabrik Ag Device for air-intermingling multifilament yarns

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899809A (en) * 1972-12-19 1975-08-19 Zellweger Uster Ag Yarn clamping device
US5146660A (en) * 1990-07-02 1992-09-15 Heberlein Maschinenfabrik Ag Device for air-intermingling multifilament yarns

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RO58377A (pl) 1975-09-15
FR2012889A1 (pl) 1970-03-27
DE1935350B2 (de) 1974-01-31
NL6910530A (pl) 1970-01-14
BR6910639D0 (pt) 1973-01-02
IE33191L (en) 1970-01-12
IE33191B1 (en) 1974-04-17
PL80188B1 (pl) 1975-08-30
DE1935350C3 (de) 1974-09-05
JPS4815695B1 (pl) 1973-05-16
BE736018A (pl) 1970-01-12
DE1935350A1 (de) 1970-01-15

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