US3043088A - Process for making bulky yarn - Google Patents

Description

July 10, 1962 A. BREEN PROCESS FOR MAKING BULKY YARN 4 SheetsSheet 1 Filed Nov. 26, 1958 m MN 55 ME R B L m V L A ATTORNEY July 10, 1962 A. L. BREEN PROCESS FOR MAKING BULKY YARN 4 Sheets-Sheet 2 Filed Nov. 26, 1958 ACETATE NYLON E T A .l- E AIV A DRAW ROLL WITH STEP ROLL NYLON TEXTURING JET -RO0STER TAIL ALTERNATE POSITION FOR T E u E u o R 0 T INVENTOR ALVIN L. BREEN ATTORNEY July 10, 1962 A. L. BREEN PROCESS FOR MAKING BULKY YARN 4 Sheets-Sheet 3 1 12 Filed Nov. 26, 1958 SPINNING CELL UP FEED ROLLS CONDITIONED ACETATE FLOCKING BOX INVENTOR ALVIN L. BREEN BY M 0 7% A ORNEY July 10, 1962 A. 1.. BREEN 3,043,038

PROCESS FOR MAKING BULKY YARN Filed Nov. 26; 1958 4 Sheets-Sheet 4 FL ATTENED STAPLE FIBER FLATTENED Lm INVENTOR ALVIN L. BREEN BY c (,7

M EQRNEY 3,043,fi88 Patented July 10, 1962 time 3,843,083 PROCESS FOR MAKHWG BULKY YARN Alvin L. Breen, West Chester, Pa., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Fiied Nov. 26, 1958, Ser. No. 776,566 17 Claims. (Ci. 57157) This invention relates to treatment of yarn, or thread, to produce yarn of greatly increased bulk, and is more particularly concerned with the production of a bulky yarn composed of plurality of individually convoluted fibers and characterized by the presence of a multitude of ring-like loops and protruding fiber ends irregularly spaced along the yarn surface.

In my copending application, Serial No. 261,635, filed Decembr 14, 1951, now Patent No. 2,783,609 I disclose the production of a novel bulky filament yarn having most of the desirable properties of ordinary spun staple yarn, but differing in being composed of substantially continuous filaments. In that yarn, bulk and an appearance resembling that of staple yarn is provided by a multitude of ring-like loops and other convolutions at random intervals along the filaments and irregularly spaced on different filaments. While this continuous filament structure is a distinct advantage for most purposes, there are textile uses which require a fuzzy, lofty or cashmerelike effect provided by a yarn which has a large number of protruding filament ends. A yarn having the combination of properties provided by free ends and bulk-giving filament convolutions would be desirable for such uses.

With the exception of silk, natural animal, vegetable and mineral fibers exist only in relatively short lengths. Yarn prepared from these natural fibers necessarily is composed of staple length fibers. Furthermore, large quantities of artificial continuous filaments are cut into staple before processing into yarn. Treatment of these staple yarns to introduce bulk-giving convolutions would be desirable regardless of whether or not free ends are required. When the desired effect requires protruding ends it would be highly desirable to provide a process for treating continuous filament yarn to impart both bulk and a multitude of protruding ends in one operation, thereby avoiding the expensive operations of cutting continuous filaments into staple and spinning the staple into yarn- An object of this invention is to provide a yarn which has a large number of protruding free ends of fiber and has an enhanced bulk provided by filament convolutions of the type characterized by the presence of ring-like loops. Another object is to provide a spun staple yarn of improved bulk characterized by the presence of a multitude of ring-like loops and protruding fiber ends irregularly spaced along the yarn surface. A further object is to provide a process for preparing yarn of improved bulk from conventional spun staple yarn. An additional object is to provide a process for treating continuous filament yarn to provide greatly increased bulk and a covering of projecting fiber ends in one operation. Other objects of the invention will become apparent from the following description and claims.

In the drawings, which illustrate preferred embodiments of the invention,

FIGURE lis a side elevation of suitable apparatus for practicing the process of this invention,

FIGURE 2 is a side elevation, partially in section, of an alternative form of nozzle,

FIGURE 3 is an end view of the nozzle shown in FIG- URE 2,

FIGURE 4 is a side elevation, partially'in section, of another form of nozzle,

FIGURE 5 is a side view showing the appearance of 81:) untwisted treated yarn prepared from continuous filament yarn (enlarged about ten times), 7

FIGURE 26 is a similar enlarged view of untwisted' treated yarn prepared from two plies of continuous filament yarn,

FIGURE 7 is a similar enlarged view of treated yarn prepared from a ply of continuous filament yarn and a ply of cotton yarn,

FIGURE 8 is a similar enlarged view of a treated yarn prepared from a single ply spun staple yarn,

FIGURE 9 is a similar enlarged view of a treated yarn prepared from a two ply spun staple yarn,

FIGURE 10 is a schematic view of the arrangement of the yarn feed, texturing jet, torque jet, take-up roll and wind-up,

FIGURE 11 is a schematic view of an alternate arrangement similar to FIGURE 10 but includes a draw roll with a step roll and a draw pin,

FIGURE 12 is a self-explanatory alternate arrangement of FIGURE 10,

FIGURE 13 is a diagrammatic section of a flocking box provided with a texturing jet,

FIGURE 14 is a schematic view of an arrangement of yarn feed rolls, flocking box, pinch rolls and wind-up,

FIGURE 15 illustrates diagrammatically in isolated strands how the staple fibers are caught inloops introduced by a jet,

FIGURE 16 shows the staple secured in the loops of FIGURE 15 which have been drawn to lock the staple fiber in place,

FIGURE 17 shows the staple fiber flattened back against the load-bearing fiber in an isolated strand,

FIGURE 18 illustrates how some strands are wrapped 0 around the filament bundle by the torque jet, and

FIGURE 19 represents a modification in which a T-shaped tube is used in place of the texturing jet[ The 'T tube may be made of any smooth material such as glass, stainless steel, or the like, and may vary in diameter from about to /2".

In accordance with this invention a novel yarn is provided which has a fuzzy to cashmere-like appearance re sulting from a covering'of projectingfiber ends and unusual bulk, as compared with staple yarns of the prior art, resulting from fibers which are convoluted into coils, loops and whorls at random intervals along their lengths and at irregular spacing on different fibers to provide a lateral interfiber spacing. The most obvious characteristics of the yarn are the combination of unusual bulkiness with the fuzzy covering provided by protruding fiber ends, but the yarn is also characterized by the presence of a multitude of ring-like loops and other convolutions in the fibers. The convolutions visible on the surface contribute desirable properties to the yarn, but the less obvious fiber convolutions within the yarn are even more important in producing bulk and resulting garment warmth of fabrics made from this yarn.

The characteristic loops in the yarn fibers have been described as ring-like because they are tiny complete loops formed by a fiber doubling back upon itself, crossing itself and then proceeding in substantially the original direction. In mathematics a curve of this type is said to have a crunode. Accordingly the characteristic loops.

will be more specifically defined as crunodal loops, and loops of this type are intended unless otherwise indicated in the following specification and claims. The majority of loops visible on the surface of the yarn are of a roughly circular shape and are properly described as ring-like. The crunodal loops inside of the yarn are not readily studied, but it is evident that pressure of surrounding filaments will tend to cause such loops to assume more complex shapes.

The fiber ends and convolutions may be held in place by a twist imparted to the yarn. A single ply yarn may have a Z or an S twist. In a multiple ply yarn the individual plies are usually twisted in one direction and the plurality of plies are usually twisted together in the opposite direction, e.g., the plies may have a Z twist and the yarn may have an S twist. Unless the convolutions have been set, as by heating the convoluted yarn, the fibers will resume their. original unconvoluted condition when the yarn is untwisted and taken apart; hence initially straight fibers will be recovered in a substantially straight condition. Of course, if the yarn fibers were initially crimped or wavy or curly, they would resume that condition on being separated from the yarn.

The yarn of this invention is prepared by a process which involves feeding yarn through a high velocity fluid jet, under conditions adapted to accomplish the double purpose of imparting bulk-giving convolutions and of providing a multitude of projecting filament ends, and then twisting the filaments together to hold the convolutions and filament ends in place. In some respects the process resembles that of my copending application, Serial No. 261,635, now Patent No. 2,783,609. However, additional critical conditions-must be observed to provide the desired covering of filament ends on the yarn surface.

The starting yarn may be composed of substantially continuous filaments or of staple length fibers, which may be natural fibers or artificial filaments cut to staple length, or the yarn may include two or more of these types.

When treating yarn composed of substantially continuous filaments in accordance with this invention, the yarn is fed through a jet operated under conditions such that the filaments are shattered at random intervals to provide the desired free ends of projecting fiber, In order to accomplish this, the jet must first open up the yarn. The filaments of an untwisted continuous filament yarn are readily separated bythe turbulence created by a high velocity jet. Twisted yarn must be untwisted before the filaments can be separated, but this action can also be achieved by the jet. Under proper conditions the jet will apply sufiicient false untwisting to the yarn filaments to permit the jet to open up the yarn, and this is true not only when the yarn is composed of a single twistedply, but also when it is composed of a plurality of plies which are individually twisted. ,Once the yarn filaments are separated, suitable jet turbulence will whip thefilaments about with such rapidity that the flex life of the material is quickly exceeded and some or many of the filaments are broken.

Operation of the jet at approximately sonic velocity, or near sonic velocity, will accomplish these objectives of opening up the yarn and whipping the filamentsabout sufiiciently to shatter them into relatively short lengths. The distance the yarn travels through the jet should be less than the average length of the fibers produced by this shattering of continuous filaments, so that the fibers will not be removed from the yarn to an objectionable extent. After the yarn is withdrawn from the jet it is twisted to hold the resulting fibers and convolutions in place. The severity of the shattering effect will vary with the flex life of the filament material, under otherwise similar conditions, but the structure resulting from the treatment can be controlled by the rate at which the yarn is passed through the jet.

Preparation of the yarn of this invention from staple yarn is simpler in at least one respect, since filamentshattering is not required, but unexpected difficulties must be overcome or else the yarn is either torn to pieces or is substantially unaffected by the treatment. The fibers of staple yarn must be held in place by a twist in the yarn, but the yarn must be untwisted while in the jet for'the treatment to have appreciable effect. At near sonic velocities the jet has been found to apply a substantial untwisting torque as well as considerable tension to the yarn. If the yarn is permitted to untwist in response to this tofque for a distance which exceeds the fiber length, the

draft yield strength of the yarn is reduced to such an extent that the accompanying jet tension is sufficient to pull the yarn apart. When the yarn is fed through the jet to a windup, it has been found that the untwisting action of the jet is limited to the length of yarn between the feed and windup devices. In other Words, the jet torque applies a false untwist to the yarn. The extent of this false untwisting action is inversely proportional to the tension applied to the yarn between feed and windup, since tension imposes a torque which opposes the jet torque. Hence the false untwist can be controlled by increasing the tension, but this does not solve the difficulty because the total of the jet tension and windup tension then exceeds the yarn strength.

In accordance with this invention it has been found that yarn which consists wholly or in part of staple-length fibers held in place by a yarn twist can be processed efiiciently when feeding the yarn to a high velocity fluid jet operated to apply a false untwist to the yarn, by snubbing the yarn passing to the jet to preventthe untwist from backing up, and again snubbing the yarn leaving the jet to prevent the untwist from carrying forward, the distance between the two snubbing points being less than the length of the staple fibers and preferably being arranged to restrict the false untwist to an effective distance of less than one-half the length of the staple fibers. The required snubbing may be accomplished by dragging the yarn over fixed surfaces, which may be the yarn entrance and exit surfaces of the jet nozzle. The 'yarn leaving the jet can be snubbed by directing it against a baffle plate which also serves to remove the yarn from the jet stream.

The action of' the jet in untwisting the yarn may be likened to a combing action. The pull of the jet stream acts to straighten the helically twisted fibers, creating a torque which untwists the yarn. A jet operated at near sonic velocity provides sufficient torque to untwist the yarns usually encountered, but it is sometimes desirable, especially with high twist single ply yarn, to provide a rotating torque jet which rotates in the opposite direction from that of the yarn twist to accentuate the false untwisting torque of the jet. Purely mechanical means for applying false twist are known in theart, but are not necessary to accomplish the false untwist described. After the fibers have been untwisted the turbulence of a high velocity jet will act to separate the fibers and form them'individually into convolutions with outwardly projecting fiber ends. Both staple yarn and continuous filament yarn can therefore be processed in a similar manner with a near sonic velocity jet to produce the desired bulky yarn having a covering of projecting fiber ends.

Plied yarn can be processed somewhat more readily than single ply yarn because the plies exert a snubbing action on each other which tends to resist untwisting of tance.

the fibers. This effect can supply a part or all of the snubbing action required to prevent the region of false untwist from being so extensive that the yarn is pulled apart. This is most easily seen in the case of a plied staple yarn of the usual type in which the singles twist is in one direction, e.g., a Z twist, and the ply twist is in the opposite direction, e.g., an S twist. An untwisting torque applied to the ply fibers also causes the plies to twist together in the opposite direction, which increase of ply twist opposes the above torque and tends to prevent the fibers from being separated for more than a short dis- If the twist is sufficiently great, as in a high twist yarn, this opposition to fiber separation provides all of the snubbing needed and it is not necessary to rely on snubbing surfaces before and after the jet. The same thing is true to a lesser extent when the plies fed to the jet are not twisted together. The plies still provide a snubbing action which opposes forces tending to untwist the fibers of a ply. Thus two separate single 'ply yarns can be fed to a jet together and processed into a single yarn in accordance with this invention with less difliculty -to intercept the yarn passage.

than a single ply. When one ply is composed of continuous filaments and another ply is composed of staple-length fibers, the continuous filaments also help resist tensions tending to exceed the draft yield strength of the staple ply.

FIGURE 1 shows a suitable arrangement of apparatus for practicing the process of this invention. The starting yarn may be supplied from any convenient source, such as a yarn package, and may come directly from the spinning process by which it is produced without intermediate wind-up. The yarn is passed between feed rolls 12 and 14, arranged to be driven so as to forward the yarn at the desired speed, which is preferably of the order of 50 to 100 yards per minute but may vary over a wide range. These feed rolls are mounted on a pedestal 16. The yarn passes through guide 18 on support 243 and into a jet nozzle supported by air supply pipe 22. The nozzle is shown in section to clarify the construction. The body portion 24 of the nozzle is hollow and is provided with a fluid exit 26 which has a venturi-like shape to create the required high velocity jet. A hollow male member 28 is threaded into the body at 36 and terminates in a cone 32 projecting into the mouth of the jet-forming exit 26. The yarn passes inside the male member, out through a hole in the projecting cone, and is carried out of the nozzle exit 26 by the jet stream created by air entering the nozzle through pipe 22. The flow of air to the jet can be regulated by valve 34 in the supply pipe. The yarn hole in cone 32 should be of a size which provides a fairly snug fit around the yarn so that the yarn is snubbed suificiently to prevent appreciable untwisting before the jet is reached, unless equivalent snubbing is provided by other means.

The yarn leaving the nozzle is deflected at right angles by a baffie plate 36 mounted on the nozzle close to the exit 26. The baffle plate accomplishes the dual purpose of terminating the action of the high velocity jet on the yarn and of snubbing the yarn against untwisting beyond this point. For reasons previously explained, the distance from the end of the cone 32 to the baffle plate must be less than the length of fibers in the treated yarn, and should preferably be such as to limit the false untwisting action of the jet to less than one-half the fiber length. Instead of the bafiie plate, a guide can be used to achieve a similar result Frequently sufiicient snubbing can be accomplished by pulling the yarn across exit face 38 of the nozzle. When suificient back snubbing is not provided by the yarn hole in cone 32 the yarn can be fed into the nozzle at an angle so that the yarn is snubbed against other parts of the male member 28.

The jet stream is operated at a near sonic velocity to separate the fibers, form them into bulk-giving convolu tions, and cause fiber ends to project from the yarn, all as described previously. The treated yarn now passes through a guide 40 located below bafile 36, and then to a pair of take-up rolls 44 and 46, which are suitably supported on pedestal 42 and are driven at a surface speed somewhat less than that of feed rolls 12, 14 to provide an overieed to the jet. The amount of overieed is one of the factors controlling the amount of bulking action accomplished in the jet and should generally be in the range of 5% to 50%, depending upon the effect desired. The percent overfeed is the percent by which the speed of yarn feed to the jet exceeds the take-up speed. The takeup rolls 44, 46 may feed to any suitable wind-up or, alternatively, one of these rolls can be a wind-up roll.

A variety of nozzles can be used instead of the one illustrated in FIGUREl to provide the required jet. A simple alternative form is shown in FIGURES 2 and 3. A metal block 50 is drilled lengthwise to provide axial yarn passage 52. An air entrance S4 is drilled at a forward angle of about 45 through one face of the block When a rotating jet stream is desired the air entrance may be made of smaller diameter than the yarn passage and be olT center to intercept the yarn passage at one side as shown in FIGURE 3. Fitting 6 56 is soldered over the air entrance; it is threaded at 58 for attachment to the air supply pipe 22 of the apparatus shown in FIGURE 1. used such as CO steam, or other vapors for special purposes.

The nozzle shown in FIGURE 4 provides advantages over the two forms already described. The housing 60 may be a standard inch plumbers T. The yarn enters through guide member 61, provided with a funnel-shaped portion 62 to receive the yarn end when stringing up. A hypodermic needle 63 of appropriate size provides a passage for conducting the yarn into the nozzle 64. The nozzle has the shape of a conventional venturi tube with the entrance 65 tapering inward so that opposite sides are at about a 20 angle with each other, and the exit 66 diverging more gradually so that opposite sides are at about a 7 angle with each other. The overall length of the venturi tube may suitably be about 1.3 inches with the diverging exit portion about 1.0 inch long. The arrangement of guide member 61, needle passage 63 and nozzle 64 makes the device self-stringing when a yarn end is fed to it.

The needle 63 is adjusted to extend into the entrance of the venturi and stop in the venturi throat 67. This adjustment is important for best performance. The manner of adjustment shown is to thread the outside of the nozzle and provide positioning and locking nuts 68, 62. The nozzle slides with a snug fit into the housing 60 until nut 68 rests against the housing. It is held in this position by springs, one of which is indicated at 70. The guide member 61 likewise slides into the housing with a snug fit until shoulder 71 is positioned against the housing. It may also be held in position by spring 79 and other simi lar springs. Advantages of this construction are that it can be taken apart easily for cleaning and the parts can be rotated to adjust the needle in the venturi throat. However, either or both parts may be held in position by set screws passing through the housing, or the parts may be threaded into the housing.

Air is supplied to the nozzle through pipe 72, which is threaded or soldered into the T housing. The air passes through the venturi around the needle 63, the venturi throat 67 being sufficient-ly larger than the needle to permit passage of the required volume of air. Gasket material may be placed in groove 73 around member 61 and groove 74 around the nozzle to prevent air leakage.

In FIGURE 13, 1 represents a flock chamber provided with an inlet 2 and an exit 3 for the yarn. Between the inlet and exit is an open space containing flock 7. The chamber is also provided with an internal air baflle. The air supplied through the texturing jet keeps the flock or linters in a state of violent agitation. The inlet 2 is usually through a texturing jet which is provided with an air supply 4 and an outlet 5 at the base of a venturi chamber 6.

The yarn is led through the inlet 2 Where it is subjected to a high speed air jet which textures the yarn forming whorls and loops. As the yarn passes through the suspended fiock 7, the fibers find their way into the interstices and loops of the yarn where they are held and entrained as the yarn passes through the exit 3 of the flocking chamber l. The yarn then proceeds as shown in FIGURE 14.

The process and products of the invention will now be illustrated by the following examples, which are not to be construed as limiting the scope of the invention.

EXAMPLE 1 The apparatus shown in FIGURE 1 was used to process a single ply of 150 denier, 4O filament, O twist, continuous filament cellulose acetate yarn. Thisyarn was fed to the nozzle at 60 yards per minute and taken up after treatment at 40 yards per minute, an overfeed of 50%. Air was supplied to the nozzle at pounds per square inch gage pressure to give the effective jet velocity of slightly greater than sonic, and an air flow through the nozzle In place of air other fluids can be.

of 2.6 cubic feet per minute measured as free air at atmospheric pressure and temperature. The bafile plate was spaced /s inch from the nozzle exit. The appearance of the untwisted treated yarn is shown in FE'GURE The filaments were convoluted and partially shattered to provide a multitude of filament loops and protruding ends as shown. This yarn was rather weak.

Two plies of the above yarn were fed together to the nozzle at 19 yards per minute and taken up after treatment at 14 yards per minute, an overfeed of 36%. The other conditions were the same as above. FIGURE 6 shows the appearance of this two-ply yarn after treatment, which exhibited the characteristic fiber loops and ends described above. When twisted the yarn was reasonably strong and processed satisfactorily into fabric.

Operation of the process as above, but without the bafile plate, or with the bafiie plate spaced one inch or more from the nozzle exit, resulted in the yarn being completely shattered into flock. Operation of the process as above, but at air pressures of 40 pounds per square inch to give air flows of less than 1.0 cubic feet per minute, measured as free air, produced bulk-giving convolutions without appreciable filament shattering, whereas pressures of 50 or more pounds per square inch produced the multitude of filament loops and ends described above.

EXAMPLE 2 Using the apparatus shown in FIGURE 1, two separate plies of yarn were fed to the nozzle. One ply was a 20 cotton count, 15 Z twist (15 turns per inch) cotton yarn. The other ply was a 200 denier, 80 filament, continuous filament acrylonitrile yarn. fed into the nozzle together at yards per minute. Air was supplied to the nozzle at 90 pounds per square inch gage pressure, which gave a flow, as free air, of 2.7 cubic feet per minute. The appearance of the resulting twoply yarn after receiving a slight twist is shown in FIG- URE 7. The bulk of both plies was markedly increased by the formation of crunodal loops and other convolutions, and cotton fibers were caused to project with a great increase in fuzziness. The cotton ply was extended inlength by the treatment, so that it wrapped around the continuous filament ply when the yarn was twisted.

An attempt to treat the cotton yarn alone under similar conditions, but without the baffle plate, resulted in the yarn being completely blown apart and reverted to unspun staple. The samewas true even' under such relatively mild conditions as 50 pounds per square inch air pressure and 10% overfeed; the cotton yarn was disintegrated.

EXAMPLE 3 A single ply, 18 cotton count, 18 Z twist sp-un yarn composed of 3-inch staple length, 3 denier, acrylonitrile fibers was processed with an apparatus similar to that shown in FIGURE 1. The yarn was taken up from the nozzle at yards per minute and the bafiie plate was located inch from the snub point provided by the restricted yarn passage into the jet stream. Air was supplied to the nozzle at 90 pounds per square inch gage, the nozzle dimensions being such as to give a flow of about 1 cubic foot per minute with an efiective jet stream velocity of slightly above sonic velocity. The appearance of the treated yarn is shown in FIGURE 8. The yarn was greatly increased in bulk and the surface was covered with ring-like loops and extending fiber ends, giving the v yarn a fuzzy or lofty appearance and feel.

EXAMPLE 4 V 'A single ply, 18 cotton count, 14 Z twist spun yarn composed of 4 /2 inch, staple length, 3 denier, acrylonitrile fibers was processed at about 100 yards per minute and 10% overfeed using an air pressure of 5 0 pounds per square inch gage. The apparatus was similar to that shown in FIGURE 1, except that the nozzle shown. in FIGURE 4 was used without a bafile plate and yarn guide 40 was located beside the nozzle so that the yarn was The yarns were 7 reorientation of the fibers in relation to each other accompanied by intertangling to the extent that the reoriented fibers are stabilized in their new positions. The net result is a peripheral expansion of the central core of the yarn with an accompanying marked increase in the number and length of free fiber ends and the formation of crunodal loops and other convolutions characteristic of the process. Some properties of fabrics prepared from the untreated and the treated yarn were as follows:

Fabric Properties Before After Bulking Bulking Weight (oz/sq. yd.) 7.1 7.2 Thickness (cm.) 0.155 0. 208 Specific volume (co/gm 6. 45 8. 55

EXAMPLE 5 A variety of spun yarns were treated in a similar way with like results. The treated yarns were all taken up from the jet at yards per minute, with other conditions as in Example 4 except as indicated in Table 1. In this table, yarn notations such as 50/2 (25 Z, 4 8 ply) 5 in., 3 d.p.f. in 5-(e) refer to a 50 cotton count, 2 ply yarn in which each of the plies has a Z twist of 25 turns per inch and the plies are twisted together in the opposite direction at 4 8 turns per inch, the fibers being 5 inches long and of 3 denier per fiber. Rayon" refers to regenerated cellulose yarn made by the viscose process. Dacron and Orlon are trademarks for yarn manufactured by E. I. du Pont de Nemours and Company and refer to polyethylene-terephthalate and polyacrylonitr-ile yarns, respectively. Nylon refers to polyhexarnethyleneadipamide yarn. The appearance of the treated yarns was similar to that shown in FIGURE 8. However, it was observed that, as the staple length was increased, the amount of loop formation in the yarn bundle increased and, of course, the frequency of protruding endsdecreased. The extent of the bulking action could be increased or decreased by varying the percent overfeed up or down from the'values given in the table,

but processing difiiculties may be encountered at overfeeds above 15%.

Table I PREFERRED PROCESS CONDITIONS FOR BULKING SPUN YARNS Air Ex. Yarn Treated Overfeed, Pressure,

Percent lbs/sq.

5(a) 18/1 (14 Z) 8-10 in., 3 d.p.f. Rayon 18 50-70 5(b) 30/1 (192) 3.5 in., 3 d.p.f. Rayon 5 40-60 5(c) 40/1 (22 Z) 6 8 in., 3 d.p.f. Rayon. 10 60-80 5(d). 10/1 (11Z) 5 1n., 3 d.p.f. Dacron 6 60-80 5(6)"-.. 5012 (25 Z, 48 ply) 5 in., 3 d.p.f. 011011.- 6 60-80 5( 18/1 (15Z) 46 in., 2.5 d.p.f. Nylon 6 60-80 1 5(g) 15/1(14 Z) 4 1n., 3 d.p.f. blend of 50% 5 50-70 Dacron, 50% Rayon fibers.

EXAMPLE 6 'A 20/1 worsted count (408 total denier) 9 Z twist spun yarn composed of 5 inch, 3 denier, acrylonitrile fibers was processed with the apparatus shown in FIG- URE 1 at a speed of 15.5 yards per minute. Air was EXAMPLE 7 A two ply, 27 cotton count, spun polyethyleneterephthalate yarn was processed at yards per minute with apparatus similar to that in FIGURE 1. The plies of this yarn were composed of 1% inch staple length, 3 denier fibers twisted together at 18 2 turns per inch, and the ply twist was 11 8. Air was supplied to the nozzle at 90. pounds per square inch gage, the flow being about 1 cubic foot of free air per minute. The yarn bulked equally well both with and without the baffle plate. The appearance of the yarn is shown in FIGURE 9 and,

except for the two-ply structure, was similar to the yarnsdescribed previously in connection with FIGURE 8. In this case the fiber and ply twists were sufficient to prevent the false untwist imparted by the jet from untwisting the yarn fibers for an undesirable distance, and snubbing against a surface Was not necessary.

An attempt was made to process a single ply, 27 cotton count, 18 Z twist yarn composed of 1%. inch, 3 denier polyethyleneterephthalate fibers under identical conditions. Without the baifle plate, or other means for snubbing the yarn close to the nozzle exit, the process could not be operated because the air stream pulled the yarn to pieces.

EXAMPLE 8 The previous examples have shown that the jet stream has suflicient false untwisting action to open up a wide variety of twisted yarns to the extent required by the process of this invention. However, it is sometimes desirable to accentuate the untwisting action by providing a rotating or torque jet stream. This has been accomplished by cutting oblique or spiralling grooves in the cone-shaped end 32 of the yarn guiding portion of the nozzle in FIGURE 1. For the purposes of the present example, however, the simple torque nozzle shown in FIGURES 2 and 3 was used with apparatus similar to that of FIGURE 1 to process single ply, 18 cotton count, 18 Z twist, spun yarn composed of 3 inch, 3 denier polyacrylonitrile fibers. Air was supplied at 90 pounds per square inch gage to give a flow at near sonic velocity of /2 cubic foot of free air per minute.

Using a nozzle having a -inch yarn passage and arranged to apply an S torque to yarn being treated,

with the yarn snubbed inch from the nozzle exit at a distance of 1 inch from the air inlet and then taken up at 15 yards per minute, the Z twist yarn processed excellently to give a multitude of ring-like loops and fuzzy ends. The yarn processed better than the same yarn did in the straight-line jet stream of Example 3, even though the air consumption was only one-half as great. This nozzle appeared as in FIGURE 3 when looking upstream at the nozzle exit. The air inlet 54 was off center to the left, giving the air stream a clockwise rotation as it came toward the observer.

An attempt was made to use a nozzle with the air inlet off center to the right, which gave a counterclockwise rotation to the air stream and applied a Z torque to the yarn, but this had no appreciable effect on the yarn. This 2 torque jet increased the Z twist of the yarn and prevented the opening action necessary for the type of bulking action described.

Cotton yarn also processed excellently under the above conditions with the S torque jet. Good results were obtained with a single ply, 18 Z twist cotton yarn having an average fiber length of 1% inches. Due to the short fiber length the bulking efiect was somewhat less than for the above 3-inch fiber length polyacrylonitrile yarn. When an attempt was made to treat the cotton yarn with the snubbing point over 1 inch from the nozzle, under otherwise identical conditions, the process was not oper able because the yarn pulled apart.

EXAMPLE 9 In Example 8 it was observed that the use of a Z torque jet nozzle increased the twist of Z twist yarn and prevented opening of the yarn, so that bulking did not take place. However, this type of treatment can be combined with heat-setting of the yarn while in the over-. twisted condition to provide a crimp bulking effect. A single ply, 18 cotton count, 15 Z twist spun yarn composed of 4-6 inch, 2.5 denier, polyhexamethyleneadipamide fibers may be processed as in Example 8, using a torque nozzle which applies a false twist of about 30 turns per inch. The nozzle may be heated to about 240250 C. to crimp set the yarn while in the false twisted condition. This produces a bulky wool-like yarn having an attractive curly crimp which imparts elasticity to the yarn. The fibers will retain their crimp when separated from the yarn.

It will often be more convenient to heat the false twisted yarn outside of the nozzle instead of heating the torque nozzle. The yarn guide 18 was spaced at a greater distance from the nozzle than shown in FIGURE 1 and a heating surface at Mil-250 C. was used to crimp set the yarn between the guide and the nozzle. The yarn was passed through the torque nozzle without snubbing so that the false twist of about 30 turns per inch backed up to the yarn guide. With other conditions as described above, a similar crimp bulking effect was obtained.

The process of Example 9 is useful with any yarn composed of fibers which can be heat set to stabilize the crimp imparted by the false twist. The treatment is enhanced by fibers which shrink during heat-setting. While the process has been illustrated with spun staple yarn, it is equally applicable to continuous filament yarns, both twisted and untwisted. The process can be combined with the treatments of any of the other examples by adding another nozzle to apply a separate false untwisting and bulking step.

For example the yarns may be composed of a blend of high and low shrinkage fiber components. This mixed shrinkage yarn may be textured through the jet as described above and then shrunk by heating the yarn while in a relaxed state, e.g. in skein form. Alternatively, the yarn may be woven or knitted into a fabric and then heat relaxed during dyeing and finishing in fabric or garment form.

EXAMPLE 10 A nylon yarn (/68/0) was fed to a jet similar to FEGURE 8 of US. 2,783,609 at 240 y.p.m. The jet was mounted so as to exhaust in an enclosure partly filled with cotton linters of about in length (FIGURES 13 and 14). The pinch rolls as illustrated in FIGURE 14 were operated at 200 y.p.m. to give an intermediate overfeed of 20%. The wind-up was operated at 230 y.p.m. to give a net overfeed of 5% and a final denier of 91. Since the calculated denier under these conditions should be 84, the linters increased the yarn weight by about 8%. The yarn sample between the flocking box and the pinch rolls had an appearance illustrated in FIGURE 15. The final yarn showed reduced loop size as shown in FIGURE 16. Many characteristic random nodes and tangles could be observed under magnification. The short length staple fibers were firmly locked within a continuous filament knot or knot snarl or tangle of random configuration and frequently compound in structure; that is, more than one continuous filament and more than one staple fiber i11 fibers; that is, about 15 millimeters, although for many" purposes staple up to about 5" may be used. In general tendency to be lost in yarn and fabric processing. Fibers of normal staple length in the range oil" to 3" are entangled less readily by the bulked yarn and therefore tend 12 32/2 worstedlcount with an 8 2 singles and a 4' 8 ply twist composed of a blend of 80% 2'd.p.f. relaxed and 20% d.p.f. high shrinkage fibers. Thisyarn was passed vertically through a nordinary glass T tube of A" diamto modify the yarn to a lesser extent in terms of the numeten Air under a pressure of 10 P'Si'g was directed her of free ends. Longer fibers, however, have the adthr h th h O t 1 l f Uh T t b t defl t the vantage of being more permanent in the final fabric. n a 6g 0 e u e 0 6c Any process which tends to entangle the longer fibers Yam from Its Vgftlcal P The Yarn Was passed through in the bulked continuous filament yarn may be used to h 'fllbfi at about 60 Y p- A Y Y haYmg Soft, advantage where the staple is long, for example, it may be 10 bulky texture was obtained; The air pressure in the tube desirable to'pass the bulked yarn through a loosely commay be varied from aboutlO p.s.i.g. to about 100 p.s.i.g. pacted bat of randomly arranged fibers- The length of It is difficultto determine the velocity of the air in the contact and compressional load on the yarn being treated tube but when the air is undelpl-essm-e in the higher should i ig tobavold unbdue g s i i range, itsspeed as it contacts the yarn is of the order of to cause re Owns ut'may e Su men 0 cause, a- D sonic velocity. The yarn processed in this manner has ment loops to become locked about the entangled staple f 1 n d h 1 d 0 an V f br k n fibers and to deform large loops into the, flattened conan i an y ery 6W 0 figuration shown in FiGURE l7. Protruding fibers and ends as Compared Wnh the proflws of f exafnples m elongated loops may be held temporarily in place by a Whldff hlgh PF l 13 used 111 conluncilon Wlth y f size to improve weaving performance and reduce snagging Containing a brittle component. The free ends pro ect characteristics in the final fabric. much further from the yarn bundle after treatment than Where improved yarn stability is the major goal, short th d v i h t ti length fiber$ $11911 as solka'Flo? 1 Wood Cellulose 3 be While the examples illustrate the use of acetate fibers 61111310376?7 g sf results' The i lengm fi 2r as the brittle or shatterable component, it is to be undertend to gmve to 50.1116 extent out. .lcrease Sta 1W 0 stood that filaments of other materials may be substiof bordeflme yams suificlently to permit Improved Warptuted more or less direc l in the e 'am les The suiting, quilling and weaving or knitting. The bulk of the y A p finished fabrics may be enhanced even after loss of the ablhty of gwan filament for Purpose dependP on Its short fibers due to the unoccupied spaces they leave betendmcy to break high spfied Jet actlon- It i has been found that th s tendency may be determined by Similarly, the bulked yarn may be passed through a a flex resistance test which consists essentially of bending liquid fiber slurry. With well dispersed fibrous material the filament repeatedly through 180 over a smooth wire Suitable length concemlfafign the yafn emellges under a specified tension. The number of cycles refi much h appearanc6 of aPlpa i Increase? quired to cause failure of the specimen is taken as a Welght of up i 50% or Tenswn apphed to i measure of its fiex resistance. The test is carried out by yarn may again be used to lock most of these fibers 1n COlldltlonll'lg filaments for at least 16 hours 111 an atplace. Heavily loaded yarns tend, however, to lose a h a F 1 h U 11 portion of the loosely attached fibers which may be mosp are or a a re Sua y blown, rubbed or shaken off and rammed to the slurry 21 filaments are tested together and the number of cycles The following experiments illustrate embodiments of 40 required-l0 cause failure 0f filamams is accepted as the invention in which two different yarns are d, one the test result. The tension applied to the specimen may of which is relatively shatterable and the other is relabe 0.15, 0.3, or 0.6 gram perdenier depending upon the tively unshatterable. brittleness of the sample. It is desirable to select a load T able II A B O D E F Remarks Example No. Core Ply Fractionable Ply Textur- Torque Windup Overinglype et, Speed, feed, Process Product Jet,p.s.i. p.s.i. y.p.m. Percent Dacron 40/27/0 Acetate 55/36/0.. 90 7 90 204 5 Fig. 10 Many endsi trewerloops than 1 Nylon 40/13/1/22..- Acetate 55/36/0 90 90 204 9 Fig. Fig. 18. Nylon 20/70/22.--. Acetate /24/0 100 80 400 3 Fig. 11 Fefivgerige eilsds Nylon 20 7 i 22. Acetate sumo 0-". 100 so 409 t Fig. simiiiirti hxfis. Giitgeln asetate d Acetate /36 L100 410 4 Fig. Similar to Ex. 13. GgenznAcetate GggtlznoAcetate 80 201 3 Fig. 12 Dilemma 2m Acet te 45 24 0 100 100 201 i 4 Fig. 11, Steam Free ends wrap used in more comtorque jet. pletely and protrude less from main yarn bundle.

* Fig. 8, 17.8. 2,783,609. A

b Torque-jet located at alternate position Fig. 12.

0 Acetate fibers with Y cross-section.

d Green implies yarn fresh from spinning unit having 5-20% residual solvent. This yarn is generallyrmuch tougher than .conditioned yarn which has been allowed to lose acetone by prolonged storage in fresh air.

EXAMPLE 18 A stretched broken Orlon tow was processed to a Mass.

factor which will result in a test lasting a minimum of 50 cycles and a maximum of 5,000 cycles. The 0.6 gram per denier load factor is satisfactory for most textile Product of the Brown Causeway Boston 7 fibers. The order of magnitude of the flex life of comr l3 monly used fiber types under a 0.6 g.p.d. load are as follows:

[In general, with other factors held constant, the tougher fibers may be stabilized by use of lower operating speed on the jet so that the individual increments of fiber length are exposed to the flexing action of the jet for a greater length of time, or by use of higher air pressure in the jet which gives a more violent flexing action in the jet. An example of the former deals with rayon which was processed at 20 y.p.m. to give a product similar to that obtained with acetate at 200 y.p.m. (roughly in inverse proportion to the tabulated flex lives).

Within a given fiber composition, a great range of flex lives may be obtained by changes in orientation and/or crystallinity. Normally, nylon and Dacron are much too tough to be fractured by .the action of a texturing jet. If, however, they are prepared in a state of W orientation and high crystallinity the flex lives may be reduced to the range of a few hundred to a few'thousand cycles. Molecular weight as indicated by relative viscosity in a suitable solvent also plays an important part in determining fiber toughness. Dacron fibers prepared from polymer with a relative viscosity of about 12 even though oriented and crystallized by normal process steps show flex lives in this same low range (100 l0,000). Usually a filament having a flex life below about 10,000 may be substituted for the acetate in the examples,

Since many different embodiments of the invention may be made without departing from the spirit and scope 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.

This application is a continuation-in-part of my copending application Serial No. 679,891, filed August 23, 1957, now Patent No. 2,869,967.

I claim:

' 1. A process for making a bulky yarn having a covering of projecting filament ends which comprises feeding a twisted yarn to a high velocity fluid jet and restraining the yarn from losing any substantial amount of its twist until the jet is reached, applying -a false untwist to the yarn by means of the jet, jetting the fluid at a near sonic velocity to convolute yarn filaments and provide a multitude of projecting filament ends, withdrawing the yarn from the jet after a travel through the jet of less than the shortest filament length, and retwisting the yarn adjacent to the jet to hold the filament eonvolution and filament ends in place.

2. The process of treating a textile yarn containing filaments which comprises forming a covering of convolutions and projecting filament ends about the yarn by subjecting it to a high velocity jet of air.

3. The process of claim 2 in which the yarn is given a false untwist by the jet of air,

4. The process of claim 2 in which the jet of air shatters some of the filaments.

5. The process of claim 4 in which the flex life of one component of the yarn is less than about 10,000. Y

6. The process of claim 4 in which the flex life of one component of the yarn is less than about 300.

7. The process of claim 2 in which the yarn contains staple fibers and the jet of air projects staple fibers.

8. The process of claim 2 in which the yarn contains staple fibers and is snubbed against a fixed surface ad- 14 jacent to the point of entry into the jet of air and is snubbed against a second fixed surface at the point of leaving the jet of air, the distance between the two snubbing points being less than the average length of the staple fibers.

9. The process of claim 2 in which two independent plies are fed together and blended into a yarn in the jet of air, at least one ply being composed of staple length fibers twisted together.

10. A process for making bulky yarn having "a covering of projecting fiber ends which comprises feeding to a high velocity jet a yarn composed of a plurality of plies of staple-length fiber, the fibers of each ply being twisted together in the same direction and the plies being twisted together in the opposite direction, applying a false untwist to the yarn by means of the jet, jetting the fluid at a near sonic velocity to convolute the fibers and to provide a multitude of projecting fiber ends and crunodal loops, withdrawing the yarn from the jet after a travel through the jet of less than the fiber length, and winding up the treated yarn, said twists of the fibers and plies being suflicient to prevent the false untwisting action of the jet from untwisting the yarn fibers for a distance of over one-half the length of the fibers.

11. The process of preparing a bulky yarn having a covering of projecting filament ends which comprises feeding a yarn to a high velocity air jet to form whorls and loops in the said yarn, passing the yarn while in this condition in contact with loose fibers and subsequently winding the yarn under tension.

12. The process of claim 14 in which the fibers are flock of from about 0.1 to 13 millimeters in length.

13. The process of claim 11 in which the fibers are in the form of staple up to about 5" in length.

14. The process of claim 11 in which the increase in the weight of the yarn due to the fiber pick-up is up to 50% 15. The process of. claim 2 in which the yarn is composed of a plurality of plies of staple-length fiber, wherein the singles twist is in one direction and the ply twist is in the opposite direction.

16. The process of claim 1 in which the twisted yarn is made up of a plurality of fiber elements, one of which has a high potential shrinkage and another has a low potential shrinkage, and thereafter shrinking the yarn by heating it While it is in a relaxed condition.

17. The process for making a bulky yarn having a covering for projecting filament ends which comprises feeding a yarn containing filaments to a high velocity gaseous jet, jetting the gas at near sonic velocity to convolute the yarn filaments and provide a multitude of projecting filament ends, withdrawing the yarn from the jet after a travel through the jet of less than the shortest filament length and thereafter winding the yarn on a package.

References Cited in the file of this patent UNITED STATES PATENTS 2,036,838 Taylor Apr, 7, 1936 2,053,123 Alles Sept. 1, 1936 2,379,824 Mummery July 3, 1945 2,489,242 Slayter et a1 Nov. 2 2, 1949 2,504,523 Harris Apr. 18, 1950 2,526,775 Slayter et al Oct. 24, 1950 2,783,609 Breen Mar. 5, 1957 2,807,862 Griset Oct. 1, 1957 2,807,864 Head Oct. 1, 1957 2,810,157 Slayter et a1 Oct. 22, 1957 2,884,756 Head May 5, 1959 2,942,402 Palm June 28, 1960

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