US2783609A - Bulky continuous filament yarn - Google Patents

Description

March 5,1957 BREEN 2,783,609

BULKY CONTINUOUS FILAMENT YARN Filed Dec. 14, 1951 2 She ets-Sheet 1 IN V EN TOR. AL VIN L .BREEN A TTORNE Y.

March 5,, 1957 BREEN 2,783,609

BULKY CONTINUOUS FILAMENT YARN Filed Dec. 14, 195] 2 Sheets-Sheet 2 g wiggv IN V EN TOR.

AL VIN LBREEN TENSION IN GRAMS TO INITIATE REMOVAL OF CONVOLUTIONS O 2 4 6 8 ID TWISTS IN TURNS PER INCH OFYARN ATTORNEY,

MJMW

BULKY CONTINUOUS FILAMENT YARN Alvin L. Breen, West Chester, Pa., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Application December 14, 1951, Serial No. 261,635

15 (Ilaims. (Cl. 57-140) This invention relates to process and apparatus for treating a bundle of continuous filaments, such as a yarn or thread, to produce a multifilament yarn of greatly increased bulk, and to the novel bulky yarn produced. More particularly, the invention relates to a bulky yarn composed of a plurality of individually convoluted filaments, and to the process and apparatus used for preparing such yarn.

With the outstanding exception of silk, all natural animal, vegetable and mineral fibers exist in only relatively short lengths. The production of yarn from such staple fiber is a time-consuming operation which usually requires a complex series of operations to align the fibers, combine them into an elongated bundle, and. draw the bundle to smaller diameter while twisting to prevent excessive slipping of adjacent fibers past each other. Further spinning operations finally produce yarn or thread useful in textile operations.

All, or nearly all, artificial fibers are produced most easily as continuous filaments. Formation of continuous filaments into yarn is much simpler than staple processing. Continuous filament yarns may be made very strong because of the absence of loose ends that are unable to transmit imposed stresses. However, because of their extreme uniformity and lack of discontinuities, conventional continuous filament yarns are much denser than their staple counterparts. The filaments lie close together in the yarn, and adjacent strands of continuous filament yarn in fabrics are closely spaced. This compactness limits the amount of insulating air space present. The lack of occluded air space greatly restricts the usefulness of such continuous filament fabrics. Lightness, covering effectiveness, and warmth-giving bulk are essential for many uses. Hence a large amount of the total continuous filament production of such fibers as viscose rayon, cellulose acetate, nylon and polyacrylonitrile has been cut into short lengths for spinning into staple yarn.

Previous efforts to produce continuous filament yarn having the desirable qualities of staple yarn have been unsuccessful. These efforts have been concerned primarily with modifying the internal structure of the fila-v ments, as by physical or chemical distortion. Mechanical crimping or twisting of filaments has produced undulating or spiralled fibers, but the efiect has been disappointing. Similar unsatisfactory results have been obtained by imparting motion to the spinning head and by chemical treatment of the spun filaments. All known methods have been unsatisfactory for one reason or another, such as insuificient bulkiness, unsatisfactory distribution of stress-bearing portions of the filaments, undesirable modification of fiber properties, impermanence of form, or complexity and expense of the operations.

It is an object of the present invention to provide continuous filament yarn having a bulkiness at least as great as that of staple yarn. spun from comparable fibers and having the same average number of filaments. per crosssection. Another object is to provide multifilament yarn nited States Patent 2,783,609 Patented Mar. 5', 1957 resembling spun staple in its desirable lightness, covering effectiveness and warmth-giving bulk but retaining the characteristic continuous filament freedom from loose ends, fuzziness and pilling. Another object is to provide bulky multifilament yarns of finer deniers than can be spun practicably from staple. A further object is to provide a process for preparing continuous filament yarn having a bull; equal or superior to that of comparable staple yarn without abrading or cutting the constituent filaments and without deforming or otherwise modifying their structure. A still further objec tis to provide such a process which is suitable for rapidly and economically treating ordinary multifilament continuous yarnto greatly increase the bulk without the use of moving mechanical parts other than in the windup. Yet another object is to provide suitable apparatus for practicing the above process. Other objects of the invention will become apparent from the following: description and claims.

In this invention, a yarn fulfilling the above objectives has: been produced, composed of a plurality of substantially continuous, individually convoluted filaments. The individual filaments have coils, loops or whorls at random intervals along their lengths. Unless otherwise indicated the term loops in the present specification refers totiny complete loops formed by a filament doubling back upon itself, crossing itself and then proceeding in substantially the originalv direction. In mathematics a curve of this type is said to have a crunode. Accordingly the term crunodal loops will be used when it is necessary to distinguish the loops characteristic of this invention from other forms of loops. The majority of loops visible on the surface of the yarn are of a roughly circular or ring-like shape. The crunodal loops inside of theyarn are not readily studied, but it is evident that pressure of surroundingfilaments will tend to cause such loops to assume more complex shapes. The most obvious characteristics of the novel continuous filament yarn are its bulkiness and the presence of a multitude of filament ring-like loops irregularly spaced along its surface. These readily visible filament loops contribute to bulkiness, but the less obvious convolutions of the filaments within the yarn provide a lateral interfilament' spacing which is important in producing. the bulk and resulting garment warmth of fabrics made from this yarn.

The convolutions of the filaments may be held in place by the twist usually imparted to yarn. When this is done, the absence of internal structural change may be shown by untwisting the yarn and taking it apart, whereupon the individual filaments will return to substantially their original condition. When ordinary straight filaments are used to prepare the bulky yarn, substantially straight filaments are obtained by unbulking the yarn. Of course, crimped, wavy or curly filaments could be processed according to this invention, and such filaments would resume their respective starting configurations when separated from the yarn. Some reduction of tensile strength below that of ordinary continuous filament yarn may be expected because, at any given point in the bulked yarn of this invention, some of the filaments may not be placed under tension when the yarn is pulled, but this may be minimized or offset by increased twist, production of the loop-within-a-loop configuration described below, or by a treatment, such as steaming, to impart a permanent set.

A similar yarn might be prepared from a bundle of continuous filaments by tedious hand manipulation. An individual filament would be separated and slackformed in the filament. The slack would be taken up by forming aminute coil or loop in the filament and holding it in place by twisting the-filament bundle or by encircling this loop by a similar convolution formedv in. a. nearby. filament. Repetition of this operation at intervals along each and every filament could eventually give the desired yarn structure.

In accordance with this invention a process has been devised for producing the described yarn structure rapidly with surprising simplicity.

In the preferred process of this invention, a stream of air or other compressible fluid is jetted rapidly from a confined space to form a turbulent region. Yarn to be treated is fed into the fluid stream so that the yarn is supported by it and the individual filaments are separated from each other and whipped about violently in the turbulent region. Merely removing these separated filaments from the turbulent region for reassembly into a yarn accomplishes the desired result of forming loops and other convolutions at random intervals along each filament and irregularly spaced on different filaments. The filaments are whipped about in the turbulent zone sufficiently to form convolutions that are retained during withdrawal, windup and further processing.

The invention will be better understood by reference to the drawings. In these drawings, which illustrate preferred embodiments of the invention,

Figure l is a schematic perspective view of suitable equipment for manufacturing bulky continuous filament yarn in accordance with the invention,

Figure 2 is a side view showing the appearance of untreated yarn being fed to the air jet (enlarged about ten times),

Figure 3 is a side View of the yarn leaving the air jet and being pulled downward out of the turbulent zone (enlarged about ten times),

Figure 4 is a side view showing the appearance of treated yarn before twist is applied (enlarged about ten times),

Figure 5 is a side view showing the appearance of bulky yarn after twist has been applied (enlarged about ten times),

Figure 6 is a graph showing how the yield point (initial loop-removal tension, measured as described below) increases with the twist applied to bulky yarn,

Figure 7 is a side view of yarn treated by a modification of the bulking process (enlarged about ten times),

Figure 8 is a modified form of air nozzle for use in practicing the invention,

Figure 9 is another modification of nozzle, and

Figure 10 shows the arrangement of filaments in a cross-sectional slice taken through fabric woven from the bulky continuous filament yarn of this invention (enlargcd about 50 times).

Referring to Figure l, the continuous filament yarn to be treated may be supplied from any suitable source, such as a yarn package supported on a creel 21. Untwisted yarn will normally be used, but twisted yarn can be used satisfactorily by increasing the filament-separating action, as by using higher pressure. The yarn can also be supplied directly from the spinning process by which it is produced, without any intermediate wind-up. The yarn 22, from whatever source is selected, passes through guides 23 and 24, between feed rolls 25 and 26, and to air nozzle 27. This nozzle consists of a compressed airpipe 28 screwed or brazed into yarn tube 29, shown partly in section. The pipe and tube are arranged at an angle so that a fiow of air is produced through the tube sufficient to carry the yarn along. The tube 29 can be as little as 1 inch long and 0.05 inch inside diameter.

The appearance of the yarn entering the air jet 27 is shown in Figure 2. The filaments are relatively straight and closely packed, giving the yarn a rod-like appearance. As shown in Figure 3, the yarn leaving the air jet is blown apart by the air stream. High speed motion pictures have shown that the individual filaments are whipped around violently by the turbulent air. As the filaments are withdrawn from the region of turbulence, they are adjacent filaments of the reforming yarn bundle. After passage through the turbulent zone and reforming into a yarn, the appearance of the bundle of filaments may be as shown in Figure 4. These filaments are only loosely grouped and a strong pull would remove the bulkiness if it were not stabilized by additional treatment, prefcrably by twisting the filaments together.

The loose bundle of filaments is directed by guides 30 and 31 to take-up rolls 32 and 33, and then passes to a wind'up device such as the down-twister shown. As is usual. with this device, the yarn is given a twist as it is wound by passing through a traveller guide 34 sliding around on ring 35 mounted on ring rail 36. The yarn is collected on spindle 37, supported by spindle rail 38 and rotated by belt 39, to form a package of finished yarn 49. The appearance of twisted yarn produced in this way is shown in Figure 5. In t e actual yarn loops may be less than 1 millimeter in size. The loops and other convolutions of individual filaments are firmly held in place by friction between filaments. Increasing the twist increases this friction between filaments and holds the convolutions more firmly in place.

Figure 6 shows the effect of increasing amounts of twist on the yield point of typical yarns. Yield point may be defined roughly as the tension required to initiate removal of the convolutions. It is measured by tensioning the yarn and plotting points on the resulting stress-strain curve. At first, a steep, nearly straight line results, representing the elastic modulus. As slippage occurs, the points generally scatter about a less steep line. Prolongation of these lines results in a point of intersection, and it is the stress at this point that is plotted as the ordinate in Figure 6. For the sample shown by curve A, the yield point started at a low value of 20 grams for zero twist, increased rapidly to a value of about 64 grams at a twist of 6 turns per inch, and levelled off at a value of about 69 grams for twists above 10 turns per inch of yarn. The yarn used for the observations from which curve A was drawn was made by the process of this invention from 150 denier, filament, 0 twist Acele (cellulose acetate yarn made by E. I. du Pont de Nemours and Company), using a feed rate of 28.9 yards per minute, an air pressure of 18 pounds per square inch gage, an air fiow of 0.49 cubic foot per minute, measured at 760 mm. of mercury pressure and 70 F., and had a final denier of 190. For common textile deniers sufficient resistance to ordinary tensions can be provided by a yield point of at least 0.15 gram per denier, although higher values are preferable.

If desired, yarn of the type shown in Figure 7 may be formed that requires little or no twist to provide relatively high yield points. The reason for the increased stability of this product is the frequent occurrence of snarls formed by entangled loops, e. g., a frequent encircling of the nodes of loops by other loops, most clearly seen at points a, b, and c in Figure 7. An attempt to stretch this modified yarn will cause tightening of many of the encircling loops, thus preventing encircled portions from unlooping, and holding the filament bundle together. As shown by curve B of Figure 6, at zero or low twists the yield point of this yarn is much higher than that of the simple product shown in Figure 5. The yarn tested to determine curve B was prepared from the same denier, 40 filament, 0 twist Acele acetate yarn used in connection with curve A, and under identical conditions except that the air pressure was increased to 25. pounds per square inch gage, giving an air flow of 0.55 cubic foot per minute. The final denier was increased to 205 as a result of the more complex yarn structure shown in Figure 7.

Yarn having the snarled or entangled loop structure is produced by a compounding of the ordinary looping action. This may be brought about in any one or more of a number of ways such as increasing the length of time the yarn is within the turbulent zone, increasing the turbulence in the zone, or setting up variations in the ex tent of turbulence. Adjustment of conditions to vary the bulky yarn produced according to this invention from the form shown in Figure to the more complex structure of Figure 7, or to any intermediate configuration, must be determined by experiment in a particular case.

In the process of this invention it is only necessary for the yarn to be passed through a zone of sufficient turbulence for a suflicient distance to separate the filaments and form them into the described convolutions. The yarn need not be passed through an air jet or nozzle of the types described, but can be passed through a turbulent stream, however formed. Likewise, air need not be used as the turbulent medium; other gases or liquids can be used. Piezoelectric or magnetostrictive transducers might be employed with similar effect, but the fluid jet method is so inexpensive and easy'to install, operate and maintain that it is naturally preferred, as the best known mode of operation.

The extremely simple air nozzle 27, shown in Figure 1, is adequate to accomplish efiective yarn treatment as described above. However, smoother operation and-more efiicient use of air is provided by the modification shown in Figure 8, in which a stream-lined air nozzle 41 is provided in place of the simple yarn tube 29' of Figure 1. Automatic threading or stringing up is assured by addition of yarn guiding member 42 having a conical inner end 43 through which the yarn end can be introduced into the air stream in position tobe carried with the air through nozzle 41. This member is threaded at 44 into a supporting body 45, providing for adjustment of the distance between cone end 43 and inlet end of air nozzle 41. Air is fed to the nozzle through pipe 28.

In the nozzle shown in Figure 9, the air is introduced into a central chamber 49 within the nozzle, passes from the chamber through a helical passageway formed by screw member 50, which gives the air a swirling motion, and leaves the nozzle through an orifice 51. It is convenient to form this orifice in a plug 52 screwed into the nozzle body. Although not necessary, it is usually desirable to break up and deflect the jetted stream of air, as with a bafile 53, which is merely a plate bent at rightangles and attached to the nozzle with a screw 54. The yarn is conducted through screw member 50 to the vicinity of the orifice by a tube 55 and is caught up by the air stream and carried out of the orifice. The best diameters for the tube and orifice will depend on the yarn being treated. For yarn of about 100 to 400 denier,. satisfactory diameters are 0.023 inch inside diameter for the tube and about 0.04 inch for the orifice. The screw member 50, which supports the tube 55, is threaded into the nozzle body. The clearance between the inner end of the tube and the orifice is adjusted by the distance the screw member is turned, a hex nut 56 being attached orformed integrally on the outer end of the member for this purpose. When a satisfactory adjustment has been found the screw member is locked in position by a hexnut 57; The outer end of tube SS'is preferably flared to receivethe yarn end when stringing-up. 7

Proper adjustment will make'the jet self stringing, i. e., when an end of yarn is placed in the'fi'ared inlet of'the tube the air stream will provide suflicient vacuum to pull the yarn through the tube and then blow it out ofthe orifice, greatly simplifying the starting up operation.

A fairly abrupt removal of the yarn from the turbulent region is conducive to formationzof a better product. This may be accomplished by guidingor pulling the yarn from the turbulent stream, as described, or the. turbulent stream may be diverted from the yarn by suitable means such as a bafile plate having ahole to admit the yarn. The bafiie platev 53 in Figure 9 may be provided'with a holethrough which the yarn is passed, the air stream. being deflected aside by the plate. The'rate of windup as compared with the rate at which yarn is supplied tothejet, will limit the amount of bulking action possible. by restricting the amount of reduction in lengthwhich occurs as the loops form.

The process and products of the invention will now be illustratedby the followingexamplegwhich are not tobe construed as limiting the scope ofthe invention.

EXAMPLE 1 Apparatus equivalent to that in Figure 1, and using the nozzle shown in Figure 1, was used to process denier, 40 filament, 0 twist, dull Acele'cellulose acetate yarn. The yarn was unwound for treatment from a spool by the tension created by the fluid jet, with a friction tension device interposed between the spool and the nozzle to limit the yarn speed to approximately 13 yards per minute (calculated from the wind-up speed and ratio of final denier to starting denier). The nozzle was supplied with nitrogen at 150 pounds per square inch gage pressure, giving a gas consumption of approximately 0.4 cubic foot per minute at 760 mm. and 70 F. The yarn was wound up at 10 yards per minute and twisted to 6 turns per inch with an up-twister. The finished bulky yarn had a denier of and the average filament loop sizewas about 0.5 mm.

The yarn treatment was repeated with difierent gas pressures and different yarn speeds to show how the size of the filament loops was affected. The changed conditions and the resulting loop sizes are given in Table I. The loop sizes are compared qualitatively because they are difiicult to classify numerically. Generally speaking, however, V. S. (very small) means that most ofthe loops were less than 0.5 mm. in size, small means" that the predominating loop size was about 0.40 to 0.75 mm., medium means that the predominating loop size was about 0.5 to 1.5 mm., and large means that most of the loops were over 1.5 mm. in size.

Apparatus of the type shown in Figure 1, but using the nozzle shown in. Figure 9, was used to process 150 denier, 100 filament, 0 twist, dull Acele yarn. The yarn'was fed to the air jet at 21 yards per minute and rewound after treatment at 18 yards per minute at a spindle speed of 5800K. P. M. to impart a Z twist of 9 turns per inch. The air pressure was 5 lbs/sq. in. and the air consumption 021 cu. ft./min. The finished yarn had a denier of 175, a tenacity of 0.71, and an elongation of 20.9%. Untreated 82 twist yarn had a denier of 150, a tenacity of 1.2, and an elongation of 26.

EXAMPLE 3 Apparatus of the type shown in Figure 1, but using the nozzle shown in Figure 9, was used to process 200 denier, 80 filament, 0.32 twist, bright yarn of Orlon acrylic fiber. The yarn was fed to the air jet at 27.5 yards per minute and rewound after treatment at 22.8 yards per minute at a spindle speed of 4700 R. P. M. to impart a Z twist of 6 turns per inch. The air pressure was 15 lbs/sq. in. and the air consumption was 0.26 cu. ft./min. The finished yarn had a denier of 258, a tenacity of 1.98 and an elongation of 17.6. Untreated 6Z twist yarn had' a denier of 200, a tenacity of 4.0 and an elongation of 19.

EXAMPLE 4 Apparatus of the. type shown in Figure l, but usingthe nozzle shown in Figure 9, was used to simultaneously blend and process 150 denier, 60 filament, 28 twist, bright textile Cordura viscose rayon yarn and150 denier, 40 filament, twist, dull Acele cellulose acetate yarn. The two yarns were unwound from separate spools and fed together to the air jet at 21 yards per minute. The treated blend was rewound at 18 yards per minute and a. spindle speed of 5820 R. P. M. to impart a 92 twist. The air pressure was lbs./ sq. in. and the air consumption was 0.25 cu. ft./min. The finished yarn blend had a denier of 342, a tenacity of 0.74, and an elongation of 12.7. A similar blend which had not received the bulking treatment had a denier of 300, a tenacity of 1.27 and an elongation of 16% In Examples 1 to 4 the treatment increased the denier by 30.0%, 16.7%, 29.0% and 14.0%, respectively. This is some indication of the extent to which filaments have been formed into convolutions, but does not indicate the surprising increase in bulk which these convolutions impart to the yarn by maintaining the filaments in spaced relationship. In general, this increase in bulk is at least 80% for packaged yarn, as shown by the following two examples:

EXAMPLE 5 Apparatus of the type shown in Figure 1, but using the nozzle shown in Figure 8, was used to process 75 denier, 30 filament, 0.32 twist, bright yarn of Orlon acrylic fiber. The yarn was fed to the air jet at 540 yards per minute, treated with air supplied at 80 lbs/sq. in., and rewound after treatment at 45.0 yards per minute with a 3S twist. The yarn was wound on a quill adapted for accurate measurement of volume at a tension of grams. The yarn bulk was 3.3 cc./ gm. as compared with 1.2 cc./ gm. for the untreated yarn, or an increase in bulk of 175%. The bulk was markedly superior to that of otherwise comparable spun stable yarn.

EXAMPLE 6 Apparatus of the type shown in Figure 1, but using the nozzle shown in Figure 8, was used to process 150 denier, 0 twist dull Acele cellulose acetate yarn. Two plies of this yarn were fed simultaneously to the air jet at 21.6 yards per minute, treated with air supplied at 10 lbs/sq. in., and the combined treated yarn was rewound at 18.0 yards per minute with an 82 twist under a tension of 68 grams. The yarn bulk was 2.0 cc./ gm. as compared with 1.1 cc./gm. for the untreated yarn, or an increase in bulk of 82%, even though the yarn was wound under considerable tension.

Since the purpose in treating yarn in accordance with this invention is to improve properties of fabrics in which it is used, the most practical way of showing the increase in bulk achieved is by observation made on such fabrics.

EXAMPLE7 Table II GOBIPARISON OF FABRICS WVOVEN FROM THREE VISCOSE RAYON YARNS Denier of Fabric Thlck- Weight, Bulk, Type of yarn yarn count ness in oz./sq. cc./gm.

inches yd.

Untreated..- 300 63 x 60 0.013 5.01 1. 9 Treated 340 64 x 68 0. 021 5. 95 2. 6 Spun staple 313 68 x 62 0. 0195 5. 65 2. 6

EXAMPLE 8 Plain weave fabrics of comparable count were prepared from untreated continuous filament yarn made of Orion acrylic fiber, from bulky yarn produced by treating the same yarn in the manner described in the previous examples, and for staple yarn spun from out filaments. The fabric bulk was determined by ASTM method D-76- 49 using an Ames gage at a pressure of 3 lbs./ sq. in. A comparison of the results is given in Table 111.

Table III COMPARISON OF FABRICS WOVEN FROM THREE DIF- FEBENT YARNS OF ORLON" ACRYLIC FIBER enier of Fabric Thiclt- Weight, Bulk, Type of yarn yarn count mess in oz./sq. ccJgrn.

inches yd.

81 x 72 0. 006 2.12 2.1 80 x (i4 0. 015 2 3b 4. 8 133 93 x 60 0. 0.125 3. 32 2. 8

The results of Examples 7 and 8 show the marked superiority in bulk of fabrics woven from the yarn of this invention in comparison with fabrics woven from ordinary continuous filament yarn. In general the increase in bulk is at least 30% when measured under the severe conditions described. The results also show that the bulky yarn may be equal, or even markedly superior, to spun yarn in this respect. The way in which the filaments are spaced is shown visually in Figure 10. Fabric woven of bulky yarn was immersed in methyl methacrylate and the monomer was polymerized to hold the filaments in position. Then a cross-sectional slice 50 microns thick was cut from the fabric. The slice was too thin to show the filament convolutions as such, but the reproduction of a photomicrograph of the slice in Figure 10 clearly shows the elfect which the convolutions have in keeping the filaments spaced apart. Intersections of loops with the plane of the cut appear as irregularly shaped dots.

Bulky yarn can be prepared by the process of this invention from any continuous textile fibers regardless of their origin. However, since the filament convolutions of each filament are held in place by adjacent filaments, the process is operative only with multifilaments. The mini mum number of filaments which can be processed satisfactorily into bulky yarn varies with the fiber, depending upon such factors as smoothness of surface, denier per filament, and the bending modulus, but any of the continuous multifilament materials referred to as yarn in the textile trade can be prepared in this bulk form. The process described has been applied successfully to the production of bulky yarn from a wide variety of commercial fibers, as indicated in Table IV. In this table the starting material is designated by numbers indicating the yarn denier, the number of filaments and the twist in turns per inch, respectively, the type of twist, if any, and the trade designation. The designation nylon refers to polyhexamethylene adipamide and polythene refers to polymerized ethylene fibers. Orlon, Acele, and Dacron are trademarks of E. I. du Pont de Nemonrs and Company for acrylic, cellulose acetate and polyester fibers, respectively. Vinyon N is a vinyl chlorideacrylonitrile copolymer produced by Union Carbide and Carbon Corp. Fortisan is a high tenacity rayon regenerated by saponification of cellulose acetate and produced by the Celanese Corporation of America. Fiberglas is spun glass produced by Owens-Corning Fiberglas Corp. The nozzle shown in Figure 8 was used in the examples of Table IV, with the indicated air pressure given in lbs./ sq. in. gage. The air consumption is in cu. ft./min. at 760 mm. and 70 F. Yarn speed is in yards per minute.

Table IV BULKY YARN PREPARATION FROM VARIOUS MATERIALS Yarn speed Ex. Starting material Air Air Final N0. pressure consump. denier Feed Windup 70-34-yz Nylon 9 gg gg gr l n 50 35 52 0.68 230 2 yon.-.. I 10 lRayom c0 41 52 0.68 169 2 y 011 11 Visc Rayon s2 00 52 0.66 101 12 70-34%2 Dacron". 50 as 43 1.20 so 13 4034%S Dacron- 31 26 52 0.88 50 14 4 -34%: :Bacron- 19 49 1.24 54 34 acron". 15 {igg g fi l n 24 1s- 50 1.25 247 1 2 y 011.... 1s ig ig g l n 24 1s 50 1.25 240 2 4 Y0!1 17 150 Acelenflfl 150 112 50 0.71 212 18 40-13%2 Nylon.... 50 1.00 40 19 300800A0e1e 4s 41 1.18 3.59 20 300-50-0 Vise. Rayon 4s 41 50 1.18 345 21 300-120-0.3z 011011 48: 41 50 1.18 354V 22 280136 ZNyl0n.. 4s 41 52 1:19 340. 23 Dacron. 48 v 42 1.25 301 so. ayon.. 24 {g gigp znfi l n 38; 2a 08 1.28 319 2 y p 5 38:8 yz o l as 20 68 1.88 203 ron g 20 :28}? g gayonfl a5 26 I as 1. 28. 243

isc. ayon.. 27 1 3s- 1 2e 1 08 1.29 201 23 Raw China Silk...-- 21 19 70 1.34 149 29 130100-sz "Vinyon N 24 1s 50 1.21 104 30 -1203z Fortisan.. 21 1r 43 1.11 31 102400 Casein 21 18v 50 0.93 130 32 -115 Fiberglas. 21 l 20 70 1.30v 112 33 66-207Z Polythene 21 18: 41 1.07 76 The advantages of. this invention aremany. The bulky 35 yarn has the desirable properties of'spunl staple yarn; and avoids the necessity of cuttingcontinuous filaments into staple and then reforming the staple into yarn. The bulky yarn is simply and economically prepared, by a process which requires little equipment, directly from the continuous filament bundle initially produced in syntheticfiber manufacture. The bulky yarn is superior to spun staple for many purposes because of its freedom from loose ends. However, it can be made to resemble spun staple in this respect, if desired, by cutting or singeing the protruding filament loops to provide loose ends. The unmodified hand of fabrics made from the bulky yarn usually is stiffer than that of corresponding staple materials, making them more suitable for use in draperies, suits, overcoats, etc.

The yarn is sufiiciently uniform to be handled easily by textile machinery and to form highly uniform fabrics without the sacrifice of bulk or of fiber interlocking characteristic of some mechanically crimped yarn having too regular a structural pattern. The yarn has been used without difiiculty on both automatic weaving and automatic knitting machines. The increased covering effectiveness of fabric made with the bulky yarn permits the production of more fabric from the same weight of yarn and, in addition, by greatly extending the utility of artificial fibers, enables them to replace expensive or scarce fibers in many uses.

Another advantage is the suitability of this process to combining filaments of extremely fine denier into light bulky yarns, having a highly uniform appearance, for which there is no spun staple counterpart. More than one kind of filament may be processed simultaneously to create yarns with a desirable blend of fiber characteristics. Intermittent impulsing of the multifilament being processed can be used to produce a novelty yarn having alternating smooth lengths and bulked regions produced according to the described process.

The simplicity of the new process permits its use at any point in yarn manufacturing or winding with no interruption of processing routine and little outlay for new equipment. Distinct advantages of the process are that itrequires little supervision, demands very little maintenance because of its freedom, from moving parts, and does not involve temperature or humidity control.

Since. many diiferent embodiments of the invention may be made without departing from the spirit andscope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claims.

What is claimed is:

1. A bulky yarn comprising a plurality of substantially continuous filaments which are individually convoluted into coils, loops and whorls at random intervals along their lengths, and characterized by the presence of a multitude of ring-like loops irregularly spaced along the yarn surface.

2. A bulky continuous filament yarn comprising a plurality of filaments which are individually looped upon themselves at random intervals along their lengths into a multitude of crunodal loops irregularly spaced on different filaments.

3. A bulky continuous filament yarn characterized by having a multitude of ring-like filament loops irregularly spaced along the yarn surface and having a multitude of filament convolutions irregularly scattered through the yarn structure providing a bulk-giving lateral interfila ment spacing.

4. A bulky continuous filament yarn having a multitude of crunodal filament loops of less than 1 millimeter in size irregularly spaced on difierent filaments and scattered through the yarn structure.

5. A bulky continuous filament yarn having a multi- H tude of crunodal filament loops which are at random intervals along the individual filaments, irregularly spaced on difierent filaments, scattered through the yarn struc ture and held in place by adjacent filaments.

6. A bulky continuous filament yarn having a multi tude of crunodal filament loops which are at random intervals along the individual filaments, irregularly spaced on different filaments, scattered through the yarn structure and held in place by a twist imparted to the yarn. 7. A bulky continuous filament yarn having a multitude of crunodal filament loops which are at random 11 intervals along the individual filaments, irregularly spaced on different filaments, and scattered through the yarn structure and further characterized by frequent occurrence of snarls formed by entangled filament loops.

8. A bulky continuous filament yarn having a multitude of crunodal filament loops which are at random intervals along the individual filaments, irregularly spaced on difierent filaments, and scattered through the yarn structure, said yarn having a yield point of at least 0.15 gram per denier.

9. A bulky continuous filament yarn having a multitude of crunodal filament loops which are at random intervals along the individual filaments, irregularly spaced on different filaments, and scattered through the yarn structure, sufficient twist being imparted to the yarn to provide a yield point of at least 0.15 gram per denier.

10. A bulky continuous filament yarn having a multitude of crunodal filament loops which are at random intervals along the individual filaments, irregularly spaced on difierent filaments, and scattered through the yarn structure, and having a suflieiently frequent occurrence of snarls formed by entangled filament loops to provide a yield point of at least 0.15 gram per denier for zero twist 11. A bulky continuous filament yarn comprising a plurality of substantially continuous filaments which are individually convoluted at random intervals along their lengths into crunodal loops which are irregularly spaced on different filaments and which loops substantially disappear when the yarn is pulled apart.

12. A bulky continuous filament yarn composed of a plurality of filaments which are individually looped upon themselves at random intervals along their lengths into a multitude of crunodal loops irregularly spaced on different filaments and having at least 80% greater bulk as packaged yarn than yarn composed of the same number of filaments which differ only in being straight.

13. A bulky continuous filament yarn composed of a plurality of filaments which are individually looped upon themselves at random intervals along their lengths into a multitude of crunodal loops irregularly spaced on different filaments, and having a denier at least 10% greater than the denier of yarn composed of the same number of filaments which differ only in being straight.

14. A bulky continuous filament yarn having the superficial appearance of staple yarn and having a bulkiness at least as great as that of staple yarn of the same overall denier spun from staple fiber of the same denier and composition as the filaments making up the bulky yarn, said bulky yarn being composed of substantially continuous filaments which are individually convoluted at random intervals along their lengths into crunodal loops which are irregularly spaced on different filaments.

15. A textile material composed of a plurality of continuous filaments and filled with voids formed by a multitude of crunodal filament loops which are at random intervals along the individual filaments, irregularly spaced on different filaments, scattered through the material and held in place by adjacent filaments.

References Cited in the file of this patent UNITED STATES PATENTS 1,755,018 Nitsch Apr. 15, 1930 1,949,604 Dreyfus et al Mar. 6, 1934 2,173,789 Nikles et a1 Sept. 19, 1939 2,197,896 Miles Apr. 23, 1940 2,225,290 Aibel Dec. 17, 1940 2,309,135 Morins Jan. 26, 1943 2,369,395 Heymann Feb. 13, 1945 2,370,112 Truitt Feb. 20, 1945 2,475,922 Stockly July 12, 1949 2,504,523 Harris Apr. 18, 1950 2,506,667 Hall May 9, 1950 2,519,493 Nakayama Aug. 22, 1950 2,532,395 Dreyfus Dec. 5, 1950 2,552,680 Johnson et al May 15, 1951 FOREIGN PATENTS 471,061 Great Britain Aug. 23, 1937

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