CA1041283A - Textured yarn and process for making same - Google Patents

Abstract

IMPROVED TEXTURED YARN AND PROCESS FOR MAKING SAME

ABSTRACT OF THE DISCLOSURE
The present invention provides a method and apparatus for forming a textured air jet interlaces yarn comprising a plurality of continuous synthetic thermoplastic filaments, the yarn being characterized by repeating sections of about 1/8-1"
in length, each section being composed of a relatively open por-tion of bulky and lofty false twisted multifilaments and a rel-atively short node portion where the multifilaments are brought closer together and are interlaced and encircled. The yarn is prepared by passing a yarn through texturing means whereby the yarn is false twisted and heat set in the twisted condition, passing the textured yarn through an air jet where the air is fed into the yarn at an angle of 45-75° and passed cocurrently through the the with the yarn to interlace the yarn and then collecting the textured, interlaced yarn. Texturing apparatus for performing the method and forming the textured yarn is also provided.

Description

The present inyention relates to a method of preparing a textured yarn and apparatus for carxying out the method.
More particularly, the invention is concerned with the provi-sion of textured yarn having improved pick resistance and processability~
Textured yarns composed of, for example, polyester, nylon and/or acetates, have found widespread use in woven and knitted fabrics, including double knit fabrics which are becoming increasingly important. While textured yarns are uniquely useful, a persistent problem with such yarns is that fabric made therefrom tends to suffer from filament picking or snagging ~hen made from textured continuous filament yarns which have little or no twist therein. This problem can be overcome if the yarns are twisted to a relatively high level to produce a faixly tight bundle but this is usually undesirable because-it is very costly and because the twisting o filament yarff produces a very hard yarn which in the case of textured yarn, completal~ destroys the textured-appearance--of the yarn and its desired bulk and loft, thus making the yarn~ unattrac-ao tive for apparel fabrie uses. Thus, it is evident that thereis a real need in the art to provide textured yarns which retain their desired characteristics of buIk and loft while at the same time having a high resistance to picking or snagging.
Another area where the use of textured yarns can be improved is in the produotion of fabrics having a heather appearance. In recent years, it has ~ecome increasingly popular to usa combinations of two cross-dyeable or different colored textured yarns to produce a heather l~ok in knit or woven fabrics. Conventionally, this has been accomplished by plying the yarn ends together on a conventional twister before knitting or weaving. However, this is an expensive and relatively complicated operation and there is, therefore, ,~ - 2 -,;~ i ,;

~412B3 considerable room for improvement here t~wards pro~iding com-binations of cross-dyeable or di~ferent colored textured yarns for use in making fabrics having a heather appearance.
In keeping with the above, one of the principal objects of the present invention to to provide a method of preparing textured yarns and fabrics containing ~he same which demonstrate improved resistance to picking and snagging.
Another objec~ of the inYentiOn is to provide apparatus for carrying out such method.
An additional object of the invention is to provide methods of preparing textured yarns which are highly desirable for use in producing fabrics having a heather appearance such method being much more convenient ~nd economical than pro-cedures hitherto used.
Thus, in one aspect, the invention provides a method of preparing a yarn comprising a plurality of continuous- syn-thetic thermoplastic filaments of a denier suitable for making fabrics,-such as wovens--or knits, said yarn being characterized by uniform repeating sections of about 1/8-1" in length, eas:h said uniform repeating section being composed of a relatively open bulky and lofty portion of false twisted multifilaments and a rela~ively short node portion where the multifilaments are brought closer together and are interlaced and encircled, comprising the steps of providing at least one end of multi-filament yarn to be textured, continuously pas~ing said yarn through texturing mean~ whereby said yarn is false ~wisted and heat set in the tMisted condition, ~ontinuously withdrawing the yarn from the texturing means and continuously feeding the same with an overfeed of from 2-10~ through a cylindrical chamber of about 1/8" diæmeter in centered coaxial relationship with the axis of said chamber, and cocurrently directing a continuous je~ of air under a source pressure of between 15-30 psig along a confined path of a cross-section smaller .
than that of said chamber having an axis which converges with respect to the axis of the chamber in the direction of yarn movement and intersects therewith at an angle of between 45-75 measured between the said chamber and said path.
In a further aspect, the invention provides apparatus for preparing a yarn comprising a plurality of continuous synthetic thermoplastic filaments of a denier suitable for making fabrics, such as wovens or knits, said yarn being characterized by uniform repeating sections of about 1/8-l"
in length, each said uniform repeating section being composed of a relatively open bulky and lofty portion of false twisted multifilaments and ~ relatively short node por-tion where the multifilaments are closer together and are interlaced and encir~led, comprising means for supporting a supply of at least one end of multifilament yarn to be textured, texturing means including heating means and false twisting means, means for ~ontinuously passing said.yarn ~hrough ~aid t~x~uring : means whereby said yarn is false twlsted and heat set in the twi,ted condition, an air jet device having a cylindrical chamber of about 1/8" diameter formed therein, a coaxial yarn feed passage of a diameter smaller than said chamber leading into said chamber and an air inlet of a cross section smaller than that of said chamber having an axis which converges with respect to the axis of the chamber in the direction of yarn movement and int~rsects therewith at an angle of between 45-75 measured between said inlet and said passage, means for con-tinuously withdrawing the yarn fro~ said texturinc3 means and ; continuously feeding the same through said yarn inlet and said chamber with an overfeed of from 2-10% and means for communicat-ing a source of air under a pressure of between 15-30 psig with 3a -~ " ,2~h said air inlet.
As descxibed more fully hereinater, a typical yarn preparation procedure in accordance with`the invention inclùdes moving one or more textured multifilament synthetic yarns through an air jet flowing cocurrently with t~e direction of yarn movement and introduced into the yarn at an angle of about 45-75 so that the filaments in the textured yarn are uniformly intermingled and entangled before the yarn is taken up. Preferably, but not necessarily, the jet treatment is combined with texturing of the yarn, e.g. the yarn is passed continuously through a conventional false-twist texturing machine and subjected to the action of the jet between texturing and the take-up of ~ .:
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- 3b -the texturing machine. ~ Z~3 The jet cau~es the filaments o the textured yarn to become periodically entangled or wound together along the length of the yarn so that there are no substantial lengths of the yarn 5 where individual filaments are free ~o slip and thus be receptive to picking. One or more textured multifilament yarns may be sub~
jected to the air jet treatment, it being appreciated that two or more of such yarns which are cross-dyeable or different col-ored can be so processed to give a combination yarn suitable for 10 providing heather effects.
The yarn of the invention can be more fully described as an air jet intermingled or interlaced textured yarn compris-ing a plurality of continuous synthetic thermoplastic filaments, the yarn being further characterized by relatively uniform re-peating sections o about 1/8-1" in length, each such section being composed of a relatively open portion o bulky and lofty false-twisted multifilaments and a relatively short node portion ~; where the multifilaments are brought closer together and are in-terlaced and encircled.
The success of the invention is due to a number of im-portant features. For one thing, it has been found that rela-tively frequent and uniformly occurring nodes or interlacing in repeating yarn sections as deined above, are important from the standpoint of pick resistance. In past uses of air jets for mingling textured yarns, nodes or interlacings have been kept to a minimum and thus the resulting products have not offered par-ticularly improved pick resistance.
Additionally, it is important for present purposes to ~` ~
~31 Z~3 use the indicated combination of false-twist texturing and air jet interlacing since the desired bulky and lofty textured product with optimum pi~k resistance cannot be obtained if the texturing or air jet is used alone.
It is also important to the success of the invention that the jet air flow be cocurrent with ~he yarn direction rath- ;
er than counter-current thereto and it is preferred that the jet have a stepped air/yarn passage. Air pressure and degree of yarn overfeed are also important as is the angle at which the air is lO mi~ed with the yarn. Other important features will also be evi-dent hereinafter.
The invention is more fully described in conjunction with the attached drawings wherein:
Figure l is a diagrammatic view of a false-twist tex- ;
turing machine including the air jet yarn interlacing feature of the invention;
Figure 2 is a vertical sectional view through a pre-; ferred form of air jet according to the invention;
`~ Figure 3 is a vertical sectional view of another sim-pler form of air jet w~ich is suitable for use herein; and Figure 4 is a perspective view of the interlaced tex- ;
tured yarn of the invention.
Referring more specifically to Figure l, which shows a texturing machine for simultaneously and separately texturing two yarnsj yarns (2) and (4) are fed into the machine from sup-ply packages (6) and (8) by pulling the yarns over the ends of the packages into the bottom rolls (lO) of the texturing ma-chine. As will be understood, the bottom rolls (lO) may be ro-r ~ --tated at a speed such as to overfeed or underfeed the yarns intothe heater (12) of the texturing machine.
~ ach of the yarns passes from the heater (12), which may be of any conventional type (e.g. an electrically heated contact surface), through its own false twist spindle (14) and (16), one of which imparts a "Z" torque and the other an "S"
torque. ~s known in ~he art, the twist applied by spindles (14) and (16) extends downwardly to heater (12) where the twist is heat set as in a conventional texturing operation.
The yarns are pulled from the spindles by a pair of feed rolls (18) which can either feed the yarns to a second heater (not shown) for relaxation or directly to the take-up rolls (20). On a double heater machine, the feed rolls (18)feed the yarns through the second heater with overfeeds which are standard in false-twist texturing and a third set of feed rolls pulls the yarn out of the second heater and feeds it onto the ~ake-up package. As indicated, Figure 1 does not show the dou-- ble heater arrangement but this is not essential for present purposes. According to the invention, the textured yarns result-ing from the false-twist heat-setting operation are fed either directly or indirectly from rolls (18) to take-up rolls (20) via ~- an interlacing air jet (22) which interlaces and entangles the textured yarns just before they are taken up on rolls (20).
i The preferred structure for air jet (22) is more fully shown in Figure 2. Basically the jet comprises a body (24), ; advantageously tubular, of steel or other metal having a stepped tubular passage or bore (26) running lengthwise thereof, the yarn or yarns and air flow passing through passage (26) in the ~ `\ :

direction of the arrows. Th~ lengths and diameters of the sev-eral s~epped bores or bore sections (a), (b) and (c) of the pas-sage may be varied althoug~ section (b), which is where the air is introduced, should be at least as long as, and preferably longer than the other two sections. In one embodiment shown in Figure 2, section (b) is about l~/o longer than sec~ion (a), the yarn inlet section, and about 50/O longer than section (c), the discharge section. These length relationships, however, can be varied although for best overall results it is desirable to main-tain the stepped feature comprising three sections of diameterincreasing from the yarn inlet to the outlet. Advantageously, the yarn inlet section (a) has the smallest diameter, the inter-mediate section (b), where the air is introduced, has a diameter from 1.5 - 3 tLmes larger than that of section (a) and the diam-eter of discharge section (3) is about 1.5 - 2 times larger than that of section (b) although it will be recognized that -other~diameter relationships may also be used. In any case, the diameter changes should be made gradually by tapering the passage ~; ~ outwardly as shown to avoid undesired turbulence.
~ir is introduced into section (b) o~ the jet through member (a8) which is provided with an air inlet passage (30) po-- sitioned at an angle of 45-75, preferably at about a 53 angle to the yarn as shown in Figure 2. O~viously the outer diameter of the bod~ (24) may be widely varied but a preferred dimension is one wherein a straight line x-x dra~n across the body (24) from the center of the air passage (30) defines a length (d) which is about 75-9~/O of the length of passage (a).
As shown in Figure 2, passage (30) is reduced in di-.

3L2~3 ameter (usually by about 2/3 - 3/4) as shown at (32) and dis-charges air into the~yarn in section (b) just beyond the point where section (b) begins. When the air flow through (32) meets the yarn flow in section (b), the filaments of the yarn or yarns are moved about in such a manner that they are interlaced and entangled into nodes at very short and regular intervals. The internodal distance is of the order of l/8" to l", preferably 1/4" to 1/2" although it will be recognized that this distance can be varied. It is important, to avoid excessive winding and twisting, that the air stream contact the yarn at essentially the exact center of the yarn.
Yigure 3 shows a simplified jet for use herein, the same numerals being used in Figures 2 and 3 to define like parts. In the embodiment of Figure 3, the diameter of the yarn passage (26) is changed only once i.rom a relatively naxrow in-let bore portion (a) to an intermingling portion (b) and the air passage (30) is of uniform diameter throughout. A pr~ferred set o dimen~ions is given in Figure 3.
The air pressure used in jet (22) has an effect on the degree of interlacing, blending and quality of the ultimate product. The optimum air pressure will depend on the nature of the yarn or yarns utilized but it appears that for best overall results an air pressure in the range of about 15-30 psig should be used for the jet structure shown in Figur~ 2. Pressures in this range give good yarn quality and sufficient entanglement and interlacing to give a product offering outstanding pick re-sistance. Higher pressures, e.g. 25-30 psig can be used in cer-tain circumstances but the yarn may begin to look hairy and ab-~ LZ~33 normal due to tight entanglement of the filaments and the bestoverall yarn quality seems to be realized at the indicated 15~3G
psig range.
~nother important variable is the degree of overfeed of the yarn into the jet. It is important to balance the over-feed at this point with the overfeed required to wind up the textured package. Too much overfeed in~o the jet gives exces-sive yarn turbulence which will form undasired loops in the jet.
An overfeed of from 2% to l~/o into the jet has been found very satisfactory. Below this degree of overfeed, interlacing effi-ciency appears to be reduced whereas above 6-~ there is some -~
tendency to get looping of the filaments and yarn entanglements which do not give a uniform product although under other condi-tions, overfeeds may be increased further.
The invention has been described above and illustrated in Figure 1 using a false-twist texturing apparatus comprising spindles for applying both ~- and Z-torque. This type of appa-ratus is well known and particularly convenient for use h~re~in `~
although any conventional ~ype of texturing apparatus may be used herein to include the air jet feature for preparing inter-mingled te~tured yarn~ The S and Z arrangement illustrated in Figure 1 has the advantage that two yarns (2) and (4) can be processed separately until the last feed roll (roll (18) in Fig-ure 1) where they are combined and fed to the jet together to be interlaced and thus form one individual yarn which has zero torque due to an equal combination of S-torque and Z-torque in individual filaments, ~hereby eliminating the need for post-heat setting or ply-twisting to control torque levels.
It is not essential for present purposes to continu-_g_ Z~3 ously texture and intermingle as illustrated in Figure 1. For example, the yarn may be pre-textured and then subjected to the air jet in two separate or discontinuous operations.
It will be appreciated that the arrangement of Figure 1 lends i~self to a numher of useful variations. Thus, in a particularly important e~bodiment, a single end of multifilament yarn can be textured, the filaments of the single end being in-termingled in the jet (22) using the arrangement of Figuxe 2 to give a yarn which is uni~uely useful in preparing pick resistant 10 knit fabrics~ In another important variation, a zero torque yarn can be prepared by combining ~ and Z yarns of equal degree of torque as indicated above. As a further alternative, two or more different colored or differently dyeable yarns may be separately false-twisted and then combined at the jet before going onto the take-up package. This eliminates the need for ply-twisting dif-f~ ferent yarns to form heather yarns and produces a more intimate blend of colors at a mwch reduced processing cost The improved pick resistance of fabrics made with in-termingled textured yarn according to the invention is effective-ly shown by ~he Mace snagging test or tester described below.
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Thus, for example, conventional 150-denier textured multifila-ment polyester yarn (not interlaced) knit in a 5wiss pique fab-ric shows a pick resistance grading of 3 to 2 when tested on t~e Mace snagging test whereas identical yarn which has been inter-laced according to the invention at 15 psig on a conventional Scragg texturing machine gives a pick resistance of 5 to 4 rat-ing for double knit fabric~ This is a very significant improve-ment since 5 is considered excellent while 3 is borderline ac-ceptable.

The snag or pick ratings cited herein were determined on a one-position Model B-612 Mace Snag Tester, manufactured by ABC Machinery Corporation, Charlotte, ~.C., based on the speci-fications of the Mace Snag Tester o~ ICI Fibres Limited. The ICI instrument, discussed in Textile Industries~ December, 1970, pages 125-6, is described in detail in the "Provisional Handbook for MK 2 'Mace' Snag Tester and Viewing Cabinet", by ~. ~.
Shepherd, Textile Development Department, ICI Fibres Limited, Hookstone Road, Harrogate, Yorks, England. Test specimens were compared with ICI photographic standards, reference numbPr DGH
1922, having ratings from 1 to 5, with intermediate numbers 4-3, 5-4, etc., 5 indicating zero snags. Only the number, not the ;~
type, of snags or picks was evaluated. Ratings cited are ~he average of two measurements per direction, wale and course, with tests re-run whenever paired ratings were more than one unit apart. The precision of the mace test, 95% confidence, is +0.5 units.
The invention is useful with any type of continuous multifilament synthetic yarn which is normally textured, e.g.
polyester, nylon, acetate, acrylic or the equivalent, or combin-ations thereof, in either the same or separate yarns. Repre-sentative of such yarns is 2/70 denier, 68 filament polyester yarn or 150 denier, 34 filament polyester yarn.
A wide variety of fabric constructions may be made with the yarns of the invention to give the indicated pick re-sistance and/or heather effect, e.g. double knits.
The interlaced textured yarn of the invention as shown ln Figure 4 comprises a plurality of continuous synthetic ther-moplastic filaments (34), the yarn being further characterizedby relatively uniform repeating sections (36) of about V8 - 1"
in length, each said section being composed of a relatively open portion (37) of bulky and lofty false-twisted multifila-ments and a relatively short node portion (38) where the multi-filaments are brought closer together and are interl~ced or en-circled.
While the invention has been described above with par-ticular refer~nce to providing improved pick resistance, or heather effects, it should be noted that the intermingled tex-tured yarns of the invention also provide other advantages in weaving and knitting fabric therefrom. Thus, for example, the intermingled or mechanically bondecL filaments prepared herein are particularly advantageous for use in warp knitting and weav ing where warping is necessary. A major problem in warping is caused by loose or flaring filament:s from a yarn bundle since most textured yarns are very open or twistless. However~ when these yarns are interlaced periodically along the length of the yarn after texturing according to the invention, flaring fila-ments and loose filament bundles are eliminated or controlledand gre~ter efficiency in knitting and warping is obtained.
The invention is illustrated by the following examples:
EX~MPLE 1 Textured yarns of 70/34 Z-torque white and 70/34 5-torque black nylon, each having 1/4 turn per inch of producertwist, were fed together through an interlacing apparatus design-ed to provide controlled overfeeding between the overfeed rolls and feed rolls to the winder. The stepped jet of Figure 2 (out-side diameter (e) 0.785 inch; bore ~a) 0.870-inch length~
0.0595-inch diameter, ~53 drill; bore (b) 0.953-inch length, 0.1285-inch diameter, ~30 drill; bore (c) 0.647-inch length, 0.1960-inch diameter~ ~9 drill; length (d) 0.7375 inch) was set 5 between the two pairs of rolls to interlace the two yarns. The interlaced yarn was wound onto a constant-tension ~ake-up. The yarns were interlaced in successive runs at eight inlet air pres-sures ranging from 5 to 40 psig, at overfeeds of 1%. The result-ing interlaced yarns were visually rated, relative to each other, 10 on a 1-to-8 scale, in terms of degree of blending (judged by colox uniformity), degree of interlacing, and overall appearance.
~?hen the results were plotted against the pressure, it was evi-dent that blending and interlacing reached a maximum at about 20-25 pounds. Yarn appearance, after improving up to about 20 15 pounds, decreased drastically with further increase in pressure.
~ The decrease was attributed to the onset of excessive interlac-'i ing and knotting. A similar tabulation of runs where pressure i~ was held at 20 psig whiLe the overfeed was vaxied from zero to 4% led to the conclusion that an overfeed of about 2% was optimum for this yarn. In general it is believed that overfeed should be as high as can be tolerated, short of looping the filaments, to provide maximum opportunity for interlacing. Subse~[uent tests showed that higher overfeeds and pressures were required as the denier-per-filament size of the yarns increased.
A similar set of runs using the jet of Figure 3 produc-ed no perceptible differences in the results. It was concluded that although the enlarged exit of the Figure 2 jet did not vis-ibly afect the quality of the output yarn, compared with the Figure 3 jet, it did both quiet ~he noise of the jet and make it easier to align the drilling of the interlacing chamber and the final placement of t~e jet. The Figure 2 jet was according-ly used in the s~bsequent examples.
Eæ~MpLE 2 Textured yarns of S-torque 70/34 Type 56 standard disperse-dyeable Dacron polyester and ~-torque 70/34 Type 92 acid-dyeable Dacron polyester were drawn from packages through the stepped jet of Example 1, using`conditions of 20 psig air :
10 pressure, 2% overfeed, and 150 ypm throughput. Both processing smoothness and product uniformity were good; and the output yarn, when converted to a single-knit jersey and dyed with an acid dyej produced a pleasing heather effect. The appearance contrasted most favorably wi~h the same jersey made from a two-;15 color plied yarn, which latter, hecause of a strong tendency to an erratic patterning, produced an irregularly barred and twill-ke:effect.
EX~MPhE 3 ~:Textured yarns of 70/17 5-tor~ue Type 56 and Z tor~ue Type 92 Dacron were successfully interlaced by the procedure of Example 1 by increasing the air pressure of the stepped jet to 28 psig and the overfeed to 3%. It was evident ~hat the yarn composition, particularly its denier per filament, was a signif~
icant factor in determining the optimum operating conditions for applying this invention.
EX~MPLE 4 Six of the stepped jets of Example 1 were installed above the top feed rolls of twelve positions of a 5cragg Model CS-12 single-heater texturing machine, equipped to texture with - - \
~L~341283 ~- and Z-torque on alternate positions, as shown in Figure 1.
~ach pair of feed yarns o 70/34 Type 92 and 70/34 Type 56 Dacron were textured with S- and Z-torque, respectively, and then passed together through a jet for interlacing, at 15 psig air pressure and 6% overfeed to the package, the overfeed being increased over earlier examples to give a good package, and the pressure reduced to prevent knotting. The yarn thus produced, showing nodes at 3/8-inch intervals, was knitted into a double-knit fabric for comparison, after dyeing, with a control fabric o~ identical structure except that the latter fabric was made from a 150/34 Type 56 Dacron, textured and set but not interlac-ed. Both fabrics were tested for pick resistance on the Mace ~ Snag Tester. The interlaced fabric had a near-perfect snag ; rating of 5-4, measured both length- and widthwise, while the other fabric had a borderline rating of 3-2 lengthwise and a low rating of 2 widthwise. Double~knit fabrics in a much loos-f er Swiss-pique stitch from the same yarns had even more pro-; nounced differences in pick resistance which, ~hough slightly lower ;than before for both fabrics, further accented the pick-resis~ant merit of the ~abrics of the invention. They had the additional advantage of an attractive heather effect when dyed.
Their pick-resistance ratings are shown in Table 1.

Table 1 Mace Test Ratings of Loose-Xnit Fabrics from Interlaced and ~on-interlaced Yarns Yarn TYpe Fabric Side Mace Ratinq Lenqth ~idth Interlaced Face 3-2 5-4 Non-interlaced Face 1 3 30 Interlaced Back 4 5-4 Non-interlac~d Back 4-3 3 4~283 EXAMP~E 5 In this example a 150/34 Type 56 Dacron was drawn from a supply package through a single-heater Model CS-12 Scragg tex-turing machine and thence through the stepped jet of Example 1.
~he yarn did not interlace well until the air pressure was in-creased to 24 psig and the overfeed to the supply pacXage to ~/0.
This example further shows the close relationship existing among the variables of ~ilament denier, air pressure, and overfeed.
EX~MPLE 6 The effects of variations in the stepped jet of Exam-ple 1 upon the entangling behavior of 150/34 Type 56 Dacron yarn are described in this example. Dimensions were as shown in Ex-~ ample 1 except where otherwise stated. Changes were made in the ;~ inlet air pressure of the jet, the angle of air impact upon the 15~ yarn, and the diameter of the interlacing chamber, as detailed in Ta~le 2. Letter references (b) and (d) in the table are to the corresponding designations in Figure 2. The yarn was fed through the first and middle rolls of an ARCT FTF double-heater machine (heaters at 200 and 210C., respectively) at 73 meters/
i minute, through the top rolls at 63.5 meters/minute, through the jet, and thence onto the take-up package at 64.1 meters/minute.
The interlacing characteristics of the yarns produced by each jet are described in Table 3.

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'' , From these results it is apparent, with this yarn, that an air inlet angle centered around 53 seems optimum, that increasing the angle decreases the distance between the nodes, that decreasing the angle increases the distance between the 5 nodes and soon seriously decreases the entangling, that minor changes in the location of the gas inlet port have no detecta~le effect, and that variations, whether up or down, in the diameter of the interlacing chamber from a value around l/8" soon become harmful to -~he interlacing process. It had earlier been recog-ni~ed that precise alignment of the inlet tube to assure thatthe air would strike the yarn dead-center in the interlacing ' tube was imperative, to avoid undesirable ~wisting caused by ro-tation of the yarn bundle.
The requency of the nocLes seems to be a function of both the diameter of the interlacing chamber and the air inlet angle, the sensitivity to minor changes in either of these par-ameters *eing fairly great. As the inlet angle rises above 53, both the length and frequency of the nodes tend to increase.
~his has the efect of simultaneously increasing the pick resis tance, but caution mus~ be taken not to go too far. Otherwise, excessive loss of loft and covering power in the yarn and the abrics made from it may occur.
It seems, further, that too small an interlacing cham-ber diameter confines the yarn excessively, while too large a chamber permits it to move about more freely than is desirable, either effect being harmful to the yarn properties.
On the whole it appears that for this yarn an inlet angle of 53, an interlacing chamber diameter of about 1/8", and an inlet air pressure of 22 psig are the optimum operating conditions. Best conditions for other yarns will differ from these to some degree, but it is well within the skill of the art to determine such conditions by simple experimentation fol-lowing the teachings of this invention.

~n attempt was made to turn the jet of Example 1 around so that the air, at 22 psig, flowed countercurrent to the 150/34 Type 56 Dacron yarn. The same yarn speed conditions were applied as in Example 6, except that, to avoid lap-ups caused by the excessive overfeed, the take-up rate had to be in-creased to 67.9 meters/minute. The resulting yarn had only a small amount of interlacing, the nodes being infrequent and easily pulled out upon extending the yarn slightly. The combin-; ation of low overfeed and limited interlaciny thus resulted in excessive loss of both covering power and pick resistance. It was concluded from this experiment that the pick-resistant yarn of thls invention could be obtained only by using a cocurrent-flow jet.
EXAMPL~ 8 . ' , .
` 20 In this example a comparison was made between the pick resistance of fabrics made from a textured interlaced yarn of this invention and a twisted yarn. The interlaced yarn was the 150/34 Type 56 Dacron o~ Example 5, while the twisted yarn was made by plying two ends of textured 100/34 Type 56 Dacron having 6 turns of Z twist. The interlaced yarn was knitted into a 6.10-g/yd2 Swiss-pique and the other into a 9~37_g/yd2 Swiss-pi~ue, and the fabrics were submitted to the Mace test. Results are s~mmarized in Table 4.

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Table 4 ~::

Mace Test Ratings of Fabrics from Interlaced and Twisted Yarns ~` Yarn Type Fabric Side Mace Ratinq . 5 ~enqth ~idth Interlaced Face 4 3 ~wisted Face 4-3 3 Interlaced Back 5-4 5-4 .

. Twisted Back 5-4 4-3 ; !:
10 Especially taking into account that the fabric from the twisted yarn had the advantages of both a higher-denier yarn and a heavier-weight ~abric, each of which should improve thè ::
pick resistance, it is believed that these results indicate that the interlaced yarn is equal or perhaps even superior to the 15 twisted yarn. ;:
EX~MPLE 9 Five samples of 150/34 Type 56 Dacron yarn were tex-i~ tured, two on the Scragg CS-12 sir-gle-heater machine and three on the ARCT FTF aouble-heater machine, for a carefully control-~, ~
~; 20 led comparison of interlaced with non-interlaced yarns. Prepa-rations o samples 1 and 2, textured on the Scragg and then autoclaved at 230F., differed only in that a stepped jet of ~xample 1 was operated, at 24 psig, above the final feed roll of ! sample 2, but not of control sample 1. Operating conditions . ~ 1 25 were: :

Bottom overfeed ~1%
Top Overfeed ~/O
~ Heater temperature 200C.
: Twist 63 tpi 30 Yarn speed 106 yds/min ~amples 3, 4 and 5 were textured on the ARCT FTF ma-.

~4~'~3 ; chine, with no jet with sample 3, an Example 1 jet at 22 psig with sample 4, and a 28 psig jet with sample 5, both jets being between the top roll and the take-up package. Operating condi-- tions were:
Bottom overfeed ~/O
Second overfeed +13.P/o Top overfeed -1.75%
~wist 63 tpi Yarn speed 73 meters/min Bottom heater temperature 200C
Top heater temperature 210C
~11 five yarns were then knitted with a Ponte-di-Roma :
stitch on an 18-cut machine, and the resulting fabrics were dyed a smoke-grey for easy observation of picks. Table 5 shows : 15 the results obtained on the mace tester.
Table 5 ~ Mace ~est Ratings of Knitted Fabrics from : Yarns Made on ~exturing Machines with and ~ithout Integral Jets Sample Face Ratinq Back Ratin g~ ~idth Lenqth ~idth 1 (not interlaced) 3 2 3 4 :.
~'. 2 (interlaced) 5-4 4 4 5-4 3 (not interlaced) 4-3 4-3 4 3 . .
25 4 (interlaced3 4 S-4 4 5-4 5 (interlaced) 4 4 4 5_4 :-;
These data show a pattern of significantly improved pick ratings of the interlaced-yarn fabrics over ~heir non~
interlaced controls. Comparison of Samples 4 and 5 indicates, Z~
on the ARCT machine and with thQ 150/34 Dacron yarn, that an air pressure of 22 psig was sufficient to provide maximum pick re-sistance and that there was no merit in applying the noisier and more expensive 28 psig air pressure.
Textile fabrics of improved pick-resistance obtained using the yarns of the present invention are the subject of U.5. Patent 3,824,776.
~, It will be appreciated from the foregoing ~hat vari-ous modifications may be made in the invention as described above. Hence the scope of the invention is defined in the fol--:, ;; lcwing laims wherein what is claimed as new is:

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Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of preparing a yarn comprising a plurality of continuous synthetic thermoplastic filaments of a denier suitable for making fabrics, such as wovens or knits, said yarn being characterized by uniform repeating sections of about 1/8 - 1" in length, each said uniform repeating section being composed of a relatively open bulky and lofty portion of false twisted multifilaments and a relatively short node por-tion where the multifilaments are brought closer together and are interlaced and encircled, comprising the steps of providing at least one end of multifilament yarn to be textured, con-tinuously passing said yarn through texturing means whereby said yarn is false twisted and heat set in the twisted condi-tion, continuously withdrawing the yarn from the texturing means and continuously feeding the same with an overfeed of from 2-10% through a cylindrical chamber of about 1/8" diameter in centered coaxial relationship with the axis of said chamber, and cocurrently directing a continuous jet of air under a source pressure of between 15-30 psig along a confined path of a cross section smaller than that of said chamber having an axis which converges with respect to the axis of the chamber in the direction of yarn movement and intersects therewith at an angle of between 45° - 75° measured between the said chamber and said path.

2. The method of claim 1 wherein the axis of the confined path of the air intersects the axis of the chamber at an angle of substantially 53°.

3. The method of claim 1 wherein two ends of yarn are separately but simultaneously textured and then interlaced together in said chamber.

4. The method of claim 2 wherein the ends are selected from the group consisting of nylon, polyester and combinations thereof.

5. Apparatus for preparing a yarn comprising a plurality of continuous synthetic thermoplastic filaments of a denier suitable for making fabrics, such as wovens or knits, said yarn being characterized by uniform repeating sections of about 1/8 - 1" in length, each said uniform repeat-ing section being composed of a relatively open bulky and lofty portion of false twisted multifilaments and a relatively short node portion where the multifilaments are closer together and are interlaced and encircled, comprising means for support-ing a supply of at least one end of multifilament yarn to be textured, texturing means including heating means and false twisting means, means for continuously passing said yarn through said texturing means whereby said yarn is false twisted and heat set in the twisted condition, an air jet device having a cylindrical chamber of about 1/8" diameter formed therein, a coaxial yarn feed passage of a diameter smaller than said chamber leading into said chamber and an air inlet of a cross section smaller than that of said chamber having an axis which converges with respect to the axis of the chamber in the direction of yarn movement and intersects therewith at an angle of between 45° - 75° measured between said inlet and said passage, means for continuously withdrawing the yarn from said texturing means and continuously feeding the same through said yarn inlet and said chamber with an overfeed of from 2-10%
and means for communicating a source of air under a pressure of between 15-30 psig with said air inlet.

6. The apparatus of claim 5 wherein said air jet device comprises a body having said cylindrical chamber formed in an intermediate section thereof, said yarn feed passage formed in a yarn inlet end section thereof, and a coaxial larger cylindrical chamber formed in a yarn discharge end section thereof, the chamber in said intermediate section having a diameter from 1.5 - 3 times larger than that of the passage in said yarn inlet end section and the chamber in said discharge end section having a diameter of about 1.5 - 2 times larger than the diameter of the chamber in said intermediate section.

7. The apparatus of claim 5 wherein the axis of said air inlet intersects the axis of said cylindrical chamber at an angle of substantially 53°.