CA1070068A - Crimpable bicomponent filament - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A crimpable, nylon bicomponent filament having a sheath of a selected polyamide on an eccentric core of a random copolymer of hexamethylene dodecanedioamide and .epsilon.-caproamide units. The copolymer contains about 25-45%
by weight of .epsilon.-caproamide units.

Description

BACKG~)UND OF THE INVENTIO~a This invention relates to yarns melt æpun ~rom syrlthetlc, linear polyamlde~ and, more particularly3 to composit2 fllaments~
Nylon filament~ and yarns have long been pre~-domin~t in the women'~ hosiery ~rket. In recen-t ~rear~3 there ha~ been a strong demand for so-cls.lled stretch hose which are much 3ma11er ~han the legs on whlch they are to be worn but stretch su~ficiently to provide not or~ly im~roved flt bu~ also a reductlon ln the nu~ber o~ 3izea re~quired ~or the normal range o~ leg ~ize3, Crlmpable filamenta p~rticularly sultable Por ~tretch ho~iery have been di~clo~ed by Olson ~n U.S. Pa~en~
No. 39 399,1080 Such filaments are able to crimp against tenslons and re~tra:~nt~ impvsed by the stitche~ in a krllt ~abr~cS thu~ co~erring excelïent stretchability on ho~iery prepared ~rom such a ~abric. Although fllamen~s o~ the compo~it~ons disclosed by Olson produce ho~iery o~
high qualityJ a need ~or ~urther iLmprovemc-,nts ~n the per~ormance ~d appearance o~ ~oda~ retch fabrics ha~
been recogn~zed.
b~8~
I~provem~t~ in durab:Lllty, flt and ~it retention hav~ now been achleved in ho~iery k~Lt :~rom a cri~pable yax~ o~ a~ lea~t one nylon filament having two collt~uous, adherent5 eccexl~ric comp~nt~, one eo~ponent bei~g a ~h~h consi~t~I~g e~ tiall~ o~ a hon~opol~mer ~elected ~rom the group cons~sting o~ polyhexamethylen~ dodecane-di.oamlde, polyhexæ~thylene adlpam~de ~d poly ~caproamld~
the other CO~pO~lel~ ~g a C~Sl"e con~i~ting e~ ntlally o~

,, ~ .

a random copolymer o~ he~camethylene dodecaxled~oa~lde and -caproamlde units~ The copolymer contain~ about 25-45%
by weigh~ of ~-caproamide unitsi, DESCRIPTION OF THE D:RAWING
In the drawingg Figure 1 is a~n enlargefl cross sectiorl o~ the co~posite filament of thle present i~vention and Fig. 2 i~ a vertical, ~ectlonal Ylew o~ a ~pi~neret ~uitable ~or lt~ production.

In each iilament lO, a contirluol;Ls sheath 12 o~
a elected polya~lde ~urround~ an eccentric core 14. An edge 16 o~ core 14 ad~acen~ e th~c}c portlon of ~he~th 12 i~ substantlally :Elat. The core ~ a copolymer of hexamethylene dodecanedio~mide (6-12 n~rlon) and -caproamide (6 nylon) unlt~ which contain~ abo~t 25-~5q~ by weight of 6 nylon units (Example IV). Better propertle~ are achi~ved at core content~ of 30-4~ by weîght 6 n~lon unit80 In thi~ respect, fllaments with core~ conltaining ~bout 3~ by ~ight of 6 ~ylon unit~ have a unique bal~nce o~ propertie~g wherea~ filaments w~kh core~ conta~ing 2û% and 50%~, r~pectively, by weight of 6 nylon unit~ ha~re be~n ~ouIld un~uita~le ~or pre~ent pu~po~e~ ample~ IVJ V ~1~ V~
Illu~trative preparation~ o* 6-lZ n~lon homo-polymer and 6-12/6 rlylon copolymer are de~cribed ln E:~carnple I .
The test fil~ment~ 10 exempli~ied herein were prepared by ~elt ~p~ing an extrudate o:f two contlnuou~, eccentrlc co~pon~nts in a sheath-core relation~hip through a ~pinneret ~s~embly 18 o~ th~ type ~how3l :ln ~ig. 2.
S;p~nneret a~embly 18 include~ ~ di~tr~butlon plate 20 having separate cavities 22, 24 from which the homopolymer and copolymer, respectively, are discharged under pres~ure tQ a distribution space 26 between plate 20 and a spinneret pl~te 28. The sheath polymer from cavity 22 passes through space 26 to passages 30, 32 a~ indicated by arrows. The core copolymer is discharged axially into pas~age 32, i.e., the two materials flow through passage 32 in substantially concentric paths. The diameter of a projection 34 and its spacing from plate 28 are chosen to provlde a pre~elected ratio of homopolymer flow rates into passages 30J 32 At the ~uncture o~ passages 30, 32 the two flows are combine~
in a side by-side relatlonship and a composite ~ilament 10 i9 extruded throu~h a reduced round ~pinning orifice 36. If trilobal or other ~ilament cro~s sections ~re desired, paR6ages 36 can be shaped ~ccordingly. Additional orifLces provided in spinneret plate 28 are ~upplied from cavitieæ 22, 24 through diætribution passages duplicating those shown in Fig. 2.
Sheath 12, along its thinne6t arc adjacent the 20 outer, convex surface of core 14, has a thickne~s of abou~ 1~ o~ the ~ilament diameter. ~or a given spi~ning ~ystem, thi~ dimension is dependent on the clearance between pro~ection 34 and æpinneret plate 28, t~pically of the order of 3 3.5 mils. (o.076-0.089 mm.~.
The m~gnitude of the di~ference in relative vi~cosities (~RV) between sheath and core polymers is important ~or obtaining opkimum oper~bility When the filament is 50-60~ by weight core and R~ ~or each component is determined using the same solve~t, the 30 6heath polymer ~V is prev~rably about 2 to 8 le~s than that o:f the cor~ polymer, Two me~hods ~or ~ r .

measur~ng RV are given ~der "De~initions and Test Descrlptions"; and both can be used for measuring core polymer RV. If ~RV is either too large or ~oo sm~
bending o~ the extruded stream occurs at the spinneret ~ace~ and the D~shape of the core ls undlesirably distortedO
Selection of ~RV to elimlnate bending of the extruded stream provides optimu~ operation.
On emergence ~rom the ~pinneret, the ~ilaments are quenched, separated into yarns o~ one or more fi~lament~
~nd then either wound on an intermediate pack~ge be~ore being drawn or advanced continuously to a draw zone, In some instanceæ, the drawn yarn is heat set before p~ckag~ng but the sensitive, precrimp~ng step di~closed by Ol~on is eli~nated. Detalled descriptions o~ several yarn pre-p~rations have been set ~o~th in the examples.
: Two types of yarn are u~ed in knitting hose or pantyhose, i.e., welt yarn~ and leg yarns~ Welt yarns are normally 40-50 denier ya~n~ wlth 6 to 13 filaments.
~ They are used to knit the panty port~on and toes o~ panty-: 20 ho~e and the welt, shadow welt, and toes o~ regular ho~e.
In the examples, the welt yarns used are commerc~ally available ~tretch yarns of the ~alse-t~lst-textured or bicomponent types~ Only the legs of either type of gar-ment are knitted ~rom the yarns described ~n the ~ollowing : 25 ex~mples. The "heel mark" is simply a sing~e end o~
~nother vls~.ble ys m knit in for a few ~titche~ o~ one cour~e. When c~anging ~rom an area knit of welt ~arn to one knit o~`leg yarn, or vice versa, the two y~rn~ are plied ~or a p~rtlon o~ one course to ~asten the area~
together~

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In knitting ho~e~ welt yarn is flr~t ied to a knitting machine. After a welt portion is knitted, it is doubled and stltched on the m~chlne to form the final welt before knitting a short undoubled portion k~own a3 the ~hadow welt. Then, leg y~rn is fed in place of welt yarn for knitting the upper leg, tran~ition9 lower leg, ankle and ~oot portions~ A switch back to welt yarn ~eed is made for ~inishing the tow.
P~ntyhv3e are similarly prepared, except that each knit tube has a longer portlon initlally knit from welt yarn to prov~de half o~ a panty ~ection~ There i~
no doubling o~ the welt as in the hose described above.
The heavler Pabric at the top o~ a tu~e for pantyhose i~
then ~lit and ~eamed to ~inish the panty. All hose or pantyhose disclosed herein were circular-knitted in a plain ~ersey stitch throughout. Some were prepared us~ng multiple-~eed machine~ but most were knit on single-f~ed machine~.
The ~traight~ uncrimped yarn of this invention handles well during knitting operattons. The unexpectedly high shrinkage ~orce o~ the copolymeric component make~
po~s~ble the development o~ mQre than adequate cri~p by shrinkage in ~bric ~orm. Heat treatment o~ the order o~
100C., a~ rout~nely used during cu6tomary fabric ~inlshlng, is ~u~icient to develop this crimp. Known crlmpable filament~ ha~e not had s~iicie~t di~ferential shrink~ge to develop adequate crimp ~or the fir~t time again~t re~traint~ pre~ent in ~abric~. Accordlngly, it h~s been nec~ary to precri~p bicomponent ~lament~ with heat se~ting ~n order to ~ub~titute relative~y ~tronger iorce~

~ - ~

of heat-set, crystalline "memory" for weaker, shrinkage ~orces .
Hose knit from crimpable, nylon yarns of this invention are very durable because o~ their high yarn tenacity at break. Variable delays between drawing and crimping have no effect on the crimp properties obtained.
Known crimped and crimpable yarns have been very sensikive to these v~riable delays, making it dif~icult to achieve uni~orm crimp properties~ especially where the yarnæ are 1~ spun in one operation and then drawn and precrimped or otherwise textured in an entirely separate operation, with yarn-packaging therebetween.
Because of its unique balance of properties, there is no need to precrimp the yarns of this invention, i.e , the as-drawn yarn can be knit directly into a fabric.
Surprisingly, the as drawn yarn provides significantly better hosiery stretch and recovery properties tha~ the same yarn precrimped (Table 2), In addition to high cost, a precrimping ætep sometimes causes periodic s~ctions of low crimp in the yarn, presumably due to random filament~
to-~ilament and ~ilament-to-heater contacts while being crimped in a nearly tensionless state. The~e low-crimp zones appear as ~law~ in knit fabrics. The as-drawn) crimpable yarns o~ this inventiDn are free ~rom such low-crimp zones. Equally significant is the fact that, since ~he inherently slow precrimping step is eliminated, crimp-able linear pol~amide bicomponent-~ilament yarns o~ this invention can be made readily in a single coupled process beginning with melting of the components and ending with packaging of yarn ready for k~itting or weaving.

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1~70~63~1 WhilP the 6-12~/6-12/6, 6~6//6 12/6 and 6//6-12/6 nylon yarns di~closed hereln (6-6 nylon is poly-hexamethylene adlp~mide; // separates sheath and core co~ponents and / separates polymer unit~ tn the copoJ.ymeric core) are especially well 3uited as ho~:ie~y leg yarn~, thelr u~e i8 by no means so limited. For in~tance9 ~elt yarn~ in cu~to~ary denler~ and count~ a:re readily prepared, Multii~ilament ya~ns of usual te~tile deniers (e.ga9 40 150 denier) are also suitable ~or the prep~ration o~ tricot or circular knlt fabric~ ~or ~tretch apparel, e.gi,, swi~uit~, men's slack~3 sports clothing and the likeO Also, the ~llaments of th~ invention may be cut to staple fibers (ordinarily ~rom 3 to 18 denier per filament) and u~ed al~ne or blended with other staple to prepare ~ab:rics3 which, on ~ubse~uent heat treatmellt, become bulky when the ~taple ~ibers o~ thl~ inven~ion ~hrin~s and crimp.
W~th the 6-12//6-12/6 nylon y~ disclosed }lerein, better levels of ~brlc sheernes~ can be ~chieved because of the ma~er in which dyes, under proper COhdi-tiO~ pa~ition preponderantly ~o the 6-12/6 nylon core~.
In thl~ re~pect9 it h~ been demon~trated that 6-12~6 ~ylon ~ccept~ acid dye~ very readily~ SimilarlyJ dl~per~e dyes ~ometimeæ ~vor the 6~12/6 n~lon core9 leaving the homopolymeric nylon sheath lighter in colorO

2~ ~
y~t~ Cea~e~/: RelatiY~ vi~co~i-ty (RV~ i~ the ~o~ution to~olvent ratlo of ab~olute vi~cosities a~
25 ~ 0~05~Co For the 6-12 polym~r~ ~nd copolymers ~nd for ths 6 nylon reported herein, a 6.166 percent by ~eight solution of the polymer in a 50% Pormlc acid (98%3J 50 ~ 8 ;

-7~6~3 phenol solvent ls used~, ~or poly}lexame-thylene adipamide (6-6 nylon) (.Ecamples IV~ V and Vïï~ the ~olvent i~ 90%
by weight f:`ormic acid (10~ ws.ter) and the polymer solution ha~ 8.4% by weight polymer ln the 801vent.
2. ~ The~e are calculated ~rom measure-ments of a trace recorded on a stress- ~train ana:Ly~er"
Sample length i8 ten inche~ (25.4 cm. ~ arld elongation is at the rate o~ ~ix ln./min. (15.2 cml,fmin, ) ,. Before tes ting, packaged yarn is conditloned for at le~t ~4 hours ~ a 72~ RH,, 25C. atmoqphereO Ter~city (T) i.8 the load ln gram~ at the point of ~ailure divided by the denler o~
the pach~ged, condltioned ~arn. Elongation (E) i3 the percent increase in length of the san~ple at the point of ~ailure. Tenacity (TB) 1~ the load in gram~ at the point o~ ~ailure divided by denier at the point o~ ~ailureO I~
i8 computed from:
TB ' T(l~E/lOO)o

3 ~ ~ A 750 denier bundle of yarn is prepared ~y w~naing the requisite number o~ tUrnB OYl a reel to ~ield a skein about 55 cm. long when su~peslded with a weight attach~dO The denier o~ tbe ~uspended ske~x~ w~ o~ cour~e) be twice that o~ the bundle, i.e~, 1500 denierO Initially, a 500 grQ. weight i8 hung from the ~u~pended skein. A~ter one mlnute9 length (a) o~
the ~kein ~ measured. The 500 gmO weight i~ t}len replaced with a 1.8 ~m. we ght to provide a ten~ile lo~Lding of 1.2 mgO/~enO~ i.eO, a tension in exce~ of that u~u~lly ex3?erlæ,nced by the yarn ln a knitted ~heer ~abric" The ~3kein wit~ th~ weight attached t~ ~ub~ected to 100Co ~te~m at atmo~pheric prs~ure ~o:r two mînutes, ~ter w~lch ,.,, g _ .

it is allowed to dry in alr for ten minutes. Then, skein length (b) is measuredn Flnally, the 1.8 gm. weight iæ
replaced by the 500 gm. weight and, after a one minute delay, skein length (c) is measured .
~ ( CE) is computed as c -~
CE(~) = 100 ~~~
Crim~ ~hrin~age (CS) is computed as a-c CS(%) - 100 a In the prior art, crimp elongation (CE) of a yarn has been relied upon as an indication of ~tretch properties to be expected in knit hose. The higher the CE, the better i~ the anticipated ~tretch. Surprisingly, the yarn~ o~ this invention generall~ provide low C~
value~ hich do not predict their outstandingly improved stretch propert~es in hose.

4. ~ The shQpe, size and eccentr~city of the core (Fig. 1~ in a blcompo-ne~tS sheath-core filament can be ob~erved and mea3ur~d microscopically~ A straight ~llament i5 first em~edded O in a para~fin wax, and then 8 micron thick slice~ are cut normal to the filament axie us~ng a microtome. A ~ingle 81~ ce i~ mounted ~or observation using transmltted light ~n an optical microscope, the ~ample be~ng covered with a ; thin film o~ oll with refractive lndex o~ about 1~53.
25 :3ither ph~e contrast or polarized light 1~ em~?loyed to m~dm~ze optical e~fect~ due to refr~ctive in~ex di~erence between ~heath and coreO T~ the event the refractive index dif~ere~ce ls too s~all for dist~nguishing sheath :Erom core, the i~ merllt is ver~ brie~ly tmmersed in a warm solution 3~ o~ a d~rk acid dye be~ore em~edding, whereby only the more ~' ~07~ 8 readily dyeable core becomes dyed. For mea~urement purpo~es, the vlewed cro~s sectio~ ls photographed along with a ~uitable scale interpo~ed in the ~ield, When the ~tarting ~llament is ~ully d rawn, the thi~nest ~heath portion (covering the curved periphery of the D-shaped core 14 in Fig. 1) can be observed but has too small a radlal thickness for precise measurementO The fiber producer can determine thi~ miminum ehea~h thicknes~ by collecting a ~ilament sample a~ it ~a~ls ~:reely from the 10 ~pinneret3 without having been drawn at all, and then measuring as above described. Filaments 50 collected are at least an order o~ magnitude larger in di~meter than are the ~ully drawn ones. The mea~ured thickness can then be scaled to the reduction in ~lze impo3ed by drawing~
15 It i~ pre~erred that the ~heath ln its thinne~t ~rc be ~ as thin ~ possible while completely cover~ng the core~
In the filament~ exempli~ied herein~ this radial thickne~
is abou~ 1% of the ~ilament diameterO

5. Hosie~_Propertie3. Ho~iery stretch (HS) and recove~y (ER) are determined after susp~ndlng a leg portion of a pantyho~e or hose irom a clamp ~astened at the welt~to-leg ~uncture. Fir~t, initial length ~Lo) i~ mea~ured. A load in gram~ of abo~t ll~OD (where D t.s den:ler o~ a ~ingle leg yarn) i~ care~ully appli.ed to the toe and, after a ~inute, extended length (L~ measured. Then, the load is r~moved ~uddenly and, a~ter a mlnute, recovered length ~L2) i~ mea~ured~ Hosiery length~ a~e mea3ured ~rom the clamp to the heel mark ~the pa~tyho~e o~ E~ample II ha~e ~ no heel mark ~nd ~re mea~ured to the toe ~unc~ture)~ ~
~S(%) = 100 1 o Ll-L2 HR(~) = 100 I~ Lo The higher the HS, the wider is the range of leg sizes a given hose can ~it~ i.e., fewer sixes o~ knit hose are required to fit the population of leg sizes. High values o~ HR indicate improved retention of rit.
~ osiery sizes are measured with a "~i~omaco" cross stretch tester ~described in U.S. Patent No. 3,444,728 to Burns, manufactured by Hickory Foundry & Machine Co., Inc., Hickory, ~orth Carolina). In Example III only9 equivalent cross-stretch measurements are made using a Jones Tester (descrlbed in U.S. Patent No~ 2,706~402 to Gaither M. Jones, Sr., manu~actured b~ Jones Machine Co., Burlington, North Carolina). Cross-stretch as reported herein is rneasured on finishedg unboarded hose in the upper leg about ~our inches (10.2 cm.) below the shadow welt and at the anklc about two inches (5.1 cm.) above the heel mark.

6. dtex. The term "dtex" is an abbrevlation ~or "decite~", a European term, and is obtained b~ multiplying denier by ,~,. '

7. precri~ . The term "precrimped" refers to yarn of one or more bicomponent filaments which has been drawn, crimped in a substantiall~ tensionless state in a heated atmosphere and then stretched to remove the crl~p be~ore packaging.

8 as-dr~wn. ~he term "as-drawn" refers to yarn which has been drawn and packaged without precrimping.
Characteriæations obtained in the test described above and other de~ailed in~ormation concerning test and control ~arn6 and hose kni~ ~rom such yarns are se~ ~olth in the ~ollowing illustrative e~amples. All pa:rts a~d percentages are by welght unless otherwise indlcated.

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6~1 EXAMPLE I
This example descr:Lbes a process ~or preparing :~lake of polyhexamethylene dodecanedioamide t6-12) homo-polyroer ~nd random copolymers comprislng hexamethylene dodecanedioamide and epsilon caproamide uni~ (6~12J'6).
An aqueou~ solution of the salt o~ hexamethylene diamine and dodeca~edioic acld (6-12 nylon salt ) is charged to an evaporator as such ~or homopolymer) or with an amount o~ epsilon caprolactam calculated to provide the desired copolymer rat lo ( ~or 6-12~ copolymer~ ~ O The solution ls e~aporated to a sollds cor~tent of about 80%
by weight. After tran~:fer to an autoclaveg the 801ution i~ heated to about 160C. a~d br~ught to a pre~sure o~
250 psig. (17f6 kg9/cm.2 gauge~. Then, an amount o~ 20%
by weight aqueous slurry of TiO~ is added to provide 0.02%
b~ wei~ht TiO2 ln the ~inal polymer (any cu~tomary amount of TiO2 delu~terant may be added, but all polymer~
exempl~fied herein contaln 0.02~ T102). While ~a~ntainlng con~tant pressure~ temperature is gradually raised to about 240C. F~Qlly, pres~ure i~ gradually reduced to ambien~ atmospheric pressure while temperature con~lnu~s to ri~e to about 250C. ~or 6-12 n~lon homopolymer ~nd about 260~C. ~or 6-12/6 nylon copolymer~. The resulta~t polymer i~ extruded under pre~sure of inert gas into strands wh~ch are quenched with water and then cut in~o 0.25 ~n~h ~o~64 cm~ ke~
EXAMPLE II
A 6~1~ nylon homopolymer ~lake ~nd a 6-12/6 ra~dom copol~amlde with 30~ by we~ght 6 nylon units are prep~red a~ de~crlbed ln ~x~mple I~ me two ilakes are - ~3 ~0~

separatel~ mel-ted using ~acuum exhau~ted screw ex-truder~, the ~V's o~ the melted polymers sampled ~u~t prior to entering the spinneret assembly being 36 and 42, re~pect-lvely. Separate gear pump~ feed the two melts at 260 3C. to a spinneret assembly with flow passage~ o~ the type shown in Fig. 2 at rate~ adjusted to provide a 40/60 weight ratio of sheath (6-12) and core (6-12/6) polymer~.
The e~truded filaments ha~e cro~s sections of the type ~hown ln Fiæ . 1 .
In their departure ~rom the ~pinneret, the fila-ment~ are air-quenched and then ~team-conditioned be~ore belng wound up a~ mono~ilaments at 516 yd./min (472 mO/~in.).
Quenching is in a 60 lnch (1.52 meter) long chimney using cross flow air at 55F. (12~8C,). Steam conditioning i~
achieved on pa~sage through a cham~er 1.92 meters long containing saturated steam at atmospheric pres~ureO
The undrawn monofilament i~ sub~equently w~th-drawn from its pack~ge, dou~led to a 2~ilament yarn and drawn over an u~heated draw pin located between ~eed ~nd draw roll~. The draw rat~o (~atio of' draw-roll to feed roll per~pheral velocitle~) is 4.67X and perlpheral ~peed of the dr~w roll is 855 yd,/min. (782 m.~min~). The drawn yarn i8 i~ediately pack~ged u~ing a ring-and~tra~eler w~ndu~ operated at a ~pindle spe~d of 7710 rpm to ~n~ert ~ twi~t of 0025~ turn~ per inch (0.1 turns/cm~). Denier of the re~ultant yarn i~ 2304 (26 dtex)~
A 30~denier 2~ ment prior a~ control yarn iB
ob-tained by plying two 15-denier co~mercial bico~ponent monof~l~ment~ The ~hea~h is o:~ 6W6 nylon ~or~ing ~2% by ~e:lghtp and the eccentric core i~ o~ 6-6~6~10~6-12 - ~4 _ :~07~

(50/31~5/18~5~ ~orming the rem~nlng 58% (6~10 identl~ie~
units o~ hexamethylene ~ebacamide). These monofilament~
are prepared with precr1mping subætantially 28 described ln Example VIII o~ U.S~ Patent No. 3J 399~108 to Olson, Propertie~ measured for the te~t yarn and one ply of the control yarn are reported in Table 1.
Table 1 15 1 Commercial Test M~nofilament ____ Tenacity (gm.~den.) 5r6 4~6 (g~/dtex) 5.0 4.1 Elongation (%) 22,2 41.2 Crlmp elongation (~) 31.9 34.3 Crimp ~hrinkage (%) 16.6 401 Ladles' medium ~ize, ~heer, support pantyhose are circu~arknitted to the ~ame f~ni~hed size ~rom the two 2-filament yarnsO Flnishing o~ the knlt garment~
be~ore wear compri~e~ loose tumble-~teaming at atmo~pheric pre~3ure, conventional ~couring and disperse dyeing and boarding on a mediu~ bo~rd ln a steam che~t conta~n~ng 220F~ (104.4C.) saturated Bteam~
A panel of twenty women who nor~all~ wear ~heer support hose wear the te3t pantyhose o~ thls i.nvention for iive day3. One pa~r ~a~ls be~ore the end o~ the te~t, and on~ te~ter di~co~t~nues testing because o~ poor iito Of the rema~n~n~ eighteen, ~lxteen *ind their pantyhose ~it Well9 and tw~ rate thelr pantyho~e too loo~O TNelve o~ the eighteen al~o r~te their pa~tyhose a~ equlval~nt to o~ better thu~ thelr u~ual Buppo~t ho~e in term~ o~
~upport provlded.

~07~06 5i A panel of nin¢teen of the above twenty women wear the control pantyhose ~or five days~ There are two early failures) and three testers discontinue testing because of poor initial ~it. Four of the fourteen who 5 ~inish the test find their pantyhose to ~lt well, but ten find they become too loose. Only ~ive o~ the ~our~een ~ind the ~upport provided equal to or better than that of thei~ usual support hose~
Hosiery stretch (HS) and hosiery recovery (HR) are mea~ured ~or unworn pantyhose ~rom the test yarn o~
thi~ example (II D) and from an otherwise identical yarn (II P) which had been precrimped according to Olson.
P~ntyho~e which had been w~rn ~or five days and which had been knit ~rom the test yarn o~ this example (II D 5~J
from an otherwi~e identical but precrimped yarn (II P 5) and ~rom the control yarn ~Il C 5) are mea~ured ~lmllarlyO
In the~e determinations, a 3.46 kg. load ia applied at the ~oot-to~toe ~unctureO Averaged results for the tw~ legs o~ each garment are report ed in Table 2 .
Table 2 HS~

II P 184 84.4 II D 5 277 94.3 II P 5 211 81.2 II C 5 171 87.,8 EXAMPLE III
mi8 example illustr~tes the preparation o~
latently cri~npable yarns using a continuous spinning-dr~wing packag~ng process. The polymer ~lakes oi ~ 16 -.. . . . . . .................... . . . .
.- ' . ' . . ~ ~ :

~07~8 Exa~ple II are us~d slmilarly to ex-trude filaments of the ~ame description. Measured on melt at the point of entry to the ~pinneret pack, R~ ~or the homopol~ner varle~3 ~rom 39.3 to 38.~ during the extru3ion and RV ~'or the copolymer variee similarly ~rom 431D3 to 4~5. The ~lu~t-e~truded ~ilaments are ~uenched in a 60~inch (1.52 m.) long chimney uslng cross ~low air at ~ 1Co They are simulta~eou~ly converged to 8-~ilament yarns" each yaxn being pulled fro~
th~ ch~mney vla ~eed roll~ at 952 ydO/minO (870.5 m./m~n. ) From the ~eed rolls, each yarn pa~se~ to a ~.irst draw roll operated ~t a perlpheral velocity of 2026 ydO~min (1853 m./min~) to provide a first stage draw ratio of 2013X~, There~ter each yarn sequentially contact~ oppo~ite ~ides of a palr of draw pins heated to 138C~ while ad~anc~n,g to a p~ir of roll~ in a hot chest mainta~ed at 120C. ~ch yarn wraps th~s pair of roll~ ~everal times and L8 deli~
vered there~rom at 3260 y~rd~/minO (2981 m./min.) ~o provide additional drawlng at ~ 1.61X draw ratioO Tot~L
dr~ by both drawi~ t~p~ p~ide~ ~ 3.42X draw ratio.
Re~idence time in the hot che~t i~ about 0.18 8econd.
I~medlatel~r subsequent to the hot che~t~ e~ch ~a~n wrap~
a let-down .roll oper~t~d ~t ~ peripher~l velocity o:~
2938 yd./m~n. 2686 m,,/min~,) and then a ~orwardin~ roll operated ~t 3012 yd./m~. ~2754 mO/min.3 peripher~l ~5 velocity. The yarn~ ~re then packaged on yarn tubes at a yarn veloc:ltg o~ about 3026 yd~,fminO (2767 m.~nln,,)~ The pack~ged 8~ilaale~ yarn ha~ a total denler of 15~,6 ~17.3 dtex~, Aver~ged propertl~ ~or this yarn, ~ncl ~o:r a control y~rn a~ de~crlbed b~lo~ are r~ported ln Ta~le 3.

.

7al~

Table 3 Te~t Control Tenacit~ (gm.~denO ) 600 '~07 ~gm.~dtex) 504 3~3 Elongation (9~) 30 "2 39 .8 Crimp elongation (~) 6 . 3 2~3 .0 Crimp ~hrinkage (,9~) 11.6 l~.4 The control yarn i3 an 18~3~denier (2003 dtex) 8-~llament yarn prepared with pr~crimping a1 descr~ bed in ~cample V~:II of Olæon~ It ha~ a 6-6 nylon F~heath ~nd ~
6-6~6-10/6-12 ( 50/31. 5~18 ~ 5 ) nylon core at a ~heath/core weight ratio and eccentricity identlc~l to the te~t yarnO
Pantyho~ are knit using the abo~e yarn~ ~or the leg portions. The panty portion i~ o~ commercial 50~den~er 10-rilament ral~e-twi~t-t~xtured 6-6 nylon yarn ~ A com-merci~l 2-reed knitting machine producing a plain ,~er~e~
stitch i~ u~ed, and the num~er of cour~e~ and ~titche~ -per couree are identical. In order to prov~de eq~
finished ~ize~ ~or the leg3 ~rom the two yarn~, it i~
~0 nece~ary to knit the legs rrOm the yarn o~ th~ lnvention ~rith l~rger ~titches, thu~ counterbalancing their high~r ~hrinkaæe. The greige hose Qre dyed in ~ commercl~l d~sa perse-dye bath, the control ho~e at 160P~o ~71~1Cs~) and the te~t hose ~t ~10Fo (98"9C.) for 45 minute~,, All ho~e are boarded on leg ~orm~ at 2~5F. (118~,3C~) in a ~t~am ~he3t. The finished ho~e are Or ~ub~tant~lly equal ~l~e a3 lndicated by mea~ure~ent~ made on th~ "Jon~
te~sr" The result~ are reported in r~ble 4 - 18 - :

.. ..
.. : .
.. . . ~ . .. ... . . . .
` . , - .-: . : . : . ' ~able 4 Test Controï
Cross ~tretchwankle (inO)9~,4 10,,0 -knee (inO )14,,2 1406 ~upper leg ~in. ) 15~5 15.1 The ho~e ~rom test yarn~ have a ilatter appearance and ~re ~reer o~ vl~ual defect~ than the control ho~eO A
panel o~ t~nty girls ranging ln ~,reight :~rom 108 to 150 pounds (49 to 68 kg.3 i~ ~elected to wear one p~ir o* each 10 type o~ ho~e ~or ~ive days~ Two o~ the testers ~lnd the panty portion o~ the te~t hose to be too tight to wear.
One pair of th~ control ho~e ~ails be:eore completion o~ the ~e~t~ The we~rer~ rate each ho~e ~eor ~it~ Re~ults are repo~ted in Table 5 ~
Te~t Control too tight ~lightl~ tight ~ 1 ~ati~actory 14 17 ~lightly loo~e 3 2 too loo~e -too tight 1 ~lightly tight 1 -t~y 10 9 ~llghtly loo~e 5 t~ loo~@ 1 3 ' .

.
_ ~9 ~

Tes t Control too tight - -slightly tight - _ sati~actvry 12 7 ~lightly loose 6 8 too loo~e - 4 It i~ apparent that the te~t hose m~intain th~ir fit better than the control ho~e.
Cri~p elongation (C~**) i~ mea~ured on yarn~
re~oved ~rom unworn ho~e (bo~rded at 118.3C. ~or 45 min.), ~rom hose worn for f~ve day~, and from two 3ets o~ hose identical in every way to the origlnal unworn hose except ~or having been boarded in steam ~or 1 minute at 104.4 and 110.0C., respectively. Crimp elongation ~c~**3 ~or yarn raveled ~rom ~ini~hed ho~e i8 determined b~ preparing a 45 meter ~ein having ~orty turns, ~llowlng the ~kein to hang ~ree Por thirty ~econds, hanglng a 108 gram weight : 20 ~roffl the skeln for about flve ~inute~9 recordlng it~ -relaxed ~ength Ll, han~ng a 500 gram welght on the ~keln, recording its extended length ~ and computlng C~* a~
lOO~L2-L~ . The computed values for CE** are reported in Tabl@ 6.
Table 6 Boarded at 118 ~ 3 C o99% 82 Worn 5 d~y; 87% 73 Boarded at llOoOCo121%~ 825~
Boarded at 104 " 4 C .138~ 77%

~ ~o ~o :
:

It i~ app~rent that 107rer boardlng te~perature~
than u~ed :~or the wear te~t hose y:leld e~en better stretch and that, ~or yarn remoYed ~rom finlshed hose, the te~t yarn~ are clearly l~proved over the control yarn~ Thi~
impro~ement i~ completely unexpected ln vlew o~ CE ~ral~le~
obtained on the yarn~ before being knltted (Table 3).
EXA~PLE IV
A 6-12 homopolymer and ~our random copol~er~ o~
6 12/6 nylon with 8Q/20, 70/309 65/35, and 60~40 weight ratios are prepared a~ de~cribed in Exa~ple Il The RV of the homopolymer i~ 38 . 0 ~ 1 c 5 and that o* the copolymer~
i~ 43 + 3 as measured on ~ampleB taken of each melt before it enter~ the ~pinneret pack durlng extrusion o~ filament~ .
The ~ilament~ ~re ~ormed by extru~ion as in Example II, ~nd are ~tructu~ally Bimllar, i.e., 40,~ by weight 6~12 sheath, 609C by w~ight 6 12/6 core9 and a ~hea*h thiclules~
along the thlrlnest ~rc o~ the ~heath ~rhich 1~ about 1% of the ~llament diameter. The ~ilament~ are ~uenched in a 60 inch (1.52 m.) chlmney u~lng cross flow air at 49 + 1~.
(905 0~5Co ) ~ Before windup and after convergenc2 to 3 ~ilament yarna, the yarns pa~ through a 7536 inch (1~92 m~) long ch~mber containing ~aturated ~team at ~tm~pherlc pre~ure~ ~indup o~ the und~awn y~rn into pack~ges i~ at 520 yd~/min. (475.5 m./mlnO). The yarn~
are subsequently withdr~wn irom their pack~ges and drawn a draw ra~io o~ 3.933X over an unheated draw pin located b~ween thè ~eed and draw roll~ of a conventlonal dr~wtwl~ter. The draw roll peripheral velocity i~ 385 yd.~in (352 mO/m~O)~ ~nd the ring--and-travel~r windulp ~ollo~ng dra~rlng i~ at a ~plndle ~p~ed of 568g rpm to ~ 21 --01~8 provlde û.411 turns~inch (00:162 turns~cm. ) o~ :3n~eFted twist .
5amples o:f each yarn are handled in three dif~erent ways between draw rol:l and windup., ïn the fir~t"
each drawn ya rn i9 packaged immedlately fol.lo~rlng drawing;
without ~urther heat treatment6, Yarns so prepared are de3cr~bed a~ I'cold-~rawn only " and are 1 denti~ied lby the code letter D (thu~g D-30 identl~ie~ "cold d~awn only" y~rn containing 30~ by weight 6 nylon unit~ in the core).
The second and third types o~ handling under tension immediately a~ter drawlng lnvolve pa~slng the drawn yarn through a 5~8 inch (14.7 cm.) long tube through which hot air i8 ~etted cocurrently at 0.7 + 0.1 ~t,3/min.
(1908 2.8 liter~/~qin. ) to provide an exit-air temperature ~ 115 ~ 2Co At the polnt o~ air e~try~ the tube is oDo8 in~
(0.20 cm.) in dlameterJ increaslng gradu~lly to 0~20 in~
(0051 cm.~ at a distance of 2.8 inJ (7.1 cm.). There the tube diameter increa~e~ a~ruptly to 0~,25 in~, (01~63 cm.) and remains constant ~or the last 3 lnO (7.6 cm~) o~ tube lengthO ~ch y~rn a~ter exit ~rom the tu~e passe~ in ~.ig-ZAg faæhion over 3 ~nub plns at a total contact angle o~ 390 ~ 15 d~gree~0 In the second type of handling the yarn 18 immediately p~ckaged under tension~ as above de~cribedO These heat treated yarns are identi~led in the table~ by code letter Ho In the th~rd t~pe o~ handling, ~ach yarn after snubbin~ ~r~t wrap~ an additional roll op~rated at a peripheral velocltg 4Q~ les~ than that of the draw roll. R~c~aglng tenslon i~ ad~usted to Ju~t re~ove the cri~p developed in the ~ery low~ten~ion reglon ~ithin and imm~d~ately ~ollo~ing the hea~ing. The~e - ~2 -precrl~ped yarn~ are i dent 1 ~le~ by code let;te:r PO They represent prior art proce~ing a~ described by Ol~on.
Properties of the Dg H and P yarn8 are repvrted in Table~ 7, 8 and 9, re~pectlvelyO
A 3-fi lament yarn iæ spun æub~tan:tially as described above except th~t the cores are 6-12/6 nylon (50/50) and the undrawn yarn i~ immedia~ely drawn 3.o8x be~ore in~tial windupO It is found that package3 o~ the undra~ yarn are un~table and that the yarn tends ~o ~lough off the package be~ore it can be unwound and d:e~a~
Drawing coupled w~h ~pinning overcomes sloughing. This ~rarn spin with great dl~iculty, ha~ very poor along the-end denier uniformity, and ha~ frequent polntæ where flla~ents are ~tuck together. It læ subsequently un~round and re-dr~wn l.lX to a d~nier of about 16. Onl~r a D-50 yarn is prepared. Re-drawing is alæo di~icult~ but enough knittable yarn to knit a few hose can be selected.
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Both heat treating and precrlmp:lng de~irably decrea~e crimp ~hrlnkageJ but they al~o diminl~h ten~city somewhat ~
I.adie~ ' stretc~ ho~e are kni~ted w~th a plaln ~ersey ~titch uslng a slngle-feed circul&r knitting n~chine with 400 75-gauge knitting needles arrangeà ln a circle about a cylinder whlch is 3.75 in. (9.52 cmO) in diametçr~, The welt and ~hadow welt are immE~ter:Lal to the ~tretch and recovery test~ to be performed, buk the~ are knitted wlth 432 and 60 couræes, re pecti~ely. The upper leg i8 knitted with 672 courses, taper~ng beg~ n~ during the next 12 cour~e~, and the lower leg compri~e~ 516 course~O Then, the ~oot i~ knittea with 372 course~ in the ~l~st o~ wh.~ch a ~econd yarn i~ i.nserted for a ~ew st~tches to ~erve a~
~ heel markO
After knitti ng~ the grelge hose (packed loo~ely in bags at 12 per bag~ are flrst tumble-~teamed in atmos~
pherlc s~ea~ :OEor 15 alinutes9 then scoured conventionally at 99 C . for ~l~keen m~nutes, then rln~ed in three 5-~nute ~ater r~n~e~, and then spun dry in the ~pin cycle of a home launderlng ~achine~, The bag~ are made by doubl~ng chee~e cloth (U.S.P0 11 or equivalent) and perman~ntly closlng three ~ides. When empt~ and :Elat, each baE5 i~
abou~ 18 X 16 inches (45.7 X 4006 cm~ ) ~ The ~illed bags are tied ~hu~ at the ~ourth ~id~. St~ll in bag~, the ho~e ar~ dyed in a conventlonal di~pers~ dye bath at 60C., for one hour and 15 ~Lnutes. ~ter ~e~reral ~hort wa~hing~
to remove exce~ dye 801utlon~ the ho~e are a~ain ~pun dr~ 1~1ng 1~ co~pleted at room temper~ture with each ~8e car@fully l~id ~lat on a ts.ble topO

.

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Hosiery stretch (HS) and hoslery recovery (~) are measured. In -thi~ determ~nation, the applied load ls a 2~27 kgo weight which i~ ~aætened to the toe and slo~ly lowered until the hose support lt without tensile shock.
Five to elght mea~urement~ are averaged to prc:vlde the hosiery stretch, hosiery recovery and croa~ ~tretch results repor~ed ln Table 10 (except ~or D-507 ~or whlch only ~e~ hose are available).
For comparison, ho~e are knitted and fi~ hecl idenkl cally using commercial 20-denier three bico~ponent-filament nylon hosiery yarn. Stretch and recoverg viEl.lue8 for a range of sizes are reported in Table llo It is apparent that measured hosiery atretch is a function of size (cross ~tretch). The increases in ho~ierg stretch for hose ~rom yarns of this inventlorl o~er hose of commercial control ~ ns are3 however, much larger than can be accounted for ,~ust by the mlnor ~ze dlf~erence~
~or purposes of compari~on with the ho~ier~
properties repo~ted ln Table 11:~, more ~ilaments ~rom polymer~ dlsclo~ed by 0180n ~re prepared. The ~rarn~ are 18-denier, 8 ~llaments, and each ~ilam~nt h~s 405~ by weight ~heath polymer and 60~o by we~ght copolymer in an eccentric core. The ~heath polymer i~ pol~h~xaE~eth~rlerle adipa~ide (6-6) and the core polymer iL~ a random copolymer ~ 5% by ~elg~t 6-6 ~:Lt~, 31.~ by we~ght he~arnethylene ~ebacamlde (6-103 unit~ and 18~5~ by ~eight hexamet~rlene dodec~edioamlde (6~:12) unit~0 Relatl~re viE~Co8~ty (P~) fo~ the~e polymer~ 18 ~easured on ~a!nple~ taken of the ~elt at a point ju~t prlor to entry into the sp~nnîng pack. The equipmerlt and gene:~l procedur~ o~ Exampl~ III

- 2~
. .

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~'7~

are used to prepare cold-drawn only9 heattreated a,nd precrimped yarns a~ described above. Process condltions for preparing these three products are reported in T~ble 12.
T~ble 13 shows CE~ ~nd CS* re~ults :Eor these yarns. Prior to this work~, crimp elongatio:n (c~ nd crimp ~hrinkage (CS) had alw~ys been mes,5ured us$ng the test3 as described under "De~in~tiorl~ and Teæt Descripti on~ 11 . It is to be noted that the C15 values i~or yarna of this inven-tlon are much lower than previously obtained u~ng precrlmped bicomponent stretch yarns but that, in spite o~ low CE, the yarns of this invention yield hose o~ vastly superior stretch propertles. In an attempt to obtain crimp elonga-tlon v~lues correlating better wlth ho~iery stretch pro~
pertie3, a ~ubst~tute test wa~ devisedO
In the substitute test, a skeln o~ yarn is formed :~rom an integral number (n) of loop~ such that total ~kein denier (2nD, where D is denier o~ the yarn~
is ~s close as poss~ble to 2084. The suspended ske$n ls o.563 m. long, Length Lo is mea~ured ~d recorded for the skein su~pended in air under a load o:~ 6g5 gm" The heav~y load i~ removed leaving only it~ aluminum ~uppor-t ~elghitlg 2.5 gm. The ske~n and attached ~uppv~ are su~pended ~n water ~t 95C. ~or one mlnute for cr~p development~, Due to water ~uoyancy, the ~upport ~ctually exert~ only about û~,75 ng",~den. of force on the skein during crlmp develop-mentt, R~moved :~rom the water, the ~kein drie~ ambient alr~, Length Ll i~ then mea~u:red arad recorded the full 695 gm. load is reapplledg and extended length L2 is - meae7lred ~d recordedO CE* ~nd CS* (the asterl~k den3ti~g ~hi~ re~ised method ~ ~re computed as:

CE~ 100 ( L2 -L~
CS* (~) = 100 (Lo~L2 )/l;o The CE* values of Table 13 for ~rlor a~t ~icom-ponent yarns are generally as great as the corre3ponding CE value~ of Table 7-9 for yarns o~ this ILnvention, but the HS values o~ Table 13 a,re generally much sn aller th~n found in Table 10 ~or yarns o~ this inventiorl~ While the reason~ are not csmpletely under~tood3 experience has ~ho~ that CE:* i~ not only a better predictor of ultim~te hosiery ~tretch thall CE, but alco it ~s a ~ar more reproducible property v~lue~

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EXAMPI,E V
This example shows the e~ect of a dif~erent homopolyamide shea-th, 6~6 nylong on yarns and hosiery ~rhich otherwise are as described in Example IV. At the same time~ additional 6 12//6-12/6 bicomponent-filament yarns are prepared in the same manner. ~hen two yarns of identical composition are shown in Tab:Les 14-17~ it means that they are identically prepared on separate days.
The polyhexamethylene adipamide (6-6 nylon) employed in forming the 6-6~/6-12/6 ~ilaments has an RV
o~ 51.4 ~ 4 2 and is spun at a melt temperature o~ about 290C. The filaments containing 6-12/6 (50/50) cores are processed ~ust like the others rather than as separately described in Example IV. Test methods are identical to those o~ Example IV.
ln Tables 14 and 16~ the listed proper-ties are averages o~ 6 -to 8 determinations. In Tables 15 and 17, the hosiery properties are averages ~or 4 hose, each knitted ~rom a separate package of the indicated yarn type The "out-of~hose" properties~ are measured on yarn removed ~rom hose a~ter measuremen-t o~ HS and HR.
The ~ilaments with 6-12/6 (50/50) cores (outside this inven-tlon), although improved over the correspondlng ones o~ Example 1~, are di~ficult to prepare and nonuni:~orrn in denier. Inter~ilament sticking is ~requent. Hose prepared uslng these ~ilaments have surprisingly high HS
values, which is not predicted by the CE* values OL the corresponding yarns. Tables 14 and 16 con~irm that CE*
is a much more reliable indicator of ultima-te hoslery s-tretch than is CE. Statistical study o~ the breaking strengths o~ yarn out-o~-ho~e (Tables 15 and 17) reveal~
that breaking strength of each yarn decre~se3 substantially linearly with lncreasing w~ight percent o~ 6 nylon ln the core of each filament. Above about 45~ 6 nylon in the core, the yarns become too weak for adequate durability ln use~
Use of 6-6 nylon as sheath polymer, rather th~n 6-12 nylon, yields sllghtly lower hosiery stretch and hosiery recovery value~, but the diminishment is slight when co~pared to stretch properties attalnable hereto~ore with known bicomponent-~ilament hoæier~ yarns, In both ca~es, the dependence of hosiery stretch on percent 6 nylon in the core is substantially the ~ame. Below 25~ 6 nylon in the core, ~tretch properties become in~dequate~ Above 45% 6 nylon in the core, the yarns become not only di~
cult to handle in spinning but al~o inadequate in breaking ~trength~

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, -- 40 _ 6~3 EXa~ LE VI
This example ~how~ the e~fect O:e va~ring sheath~
core weight ratio ~, The 3ample ideNti~ied a3 D-30 ln Example IV h~ a 6-12 sheath and a 6-12~6 core with 305 5 by weight 6 units. Sampl~ J and K are prep~red a~
described for D-30 in Exa~ple TV except ~or sheath/core welght ratioO Sheath/core weight ratio i~ varied by ad~u~ting the ~low rate~ of' the two melt~ into the 3pinneret assembly. Yam properties are reported in Table 18.
T;~ble 18 D-~ J K
_~_ __ sheath/core wgt . ratio 40/60 45/55 35/65 Ter~city (gmO/denO ) 5.3 5.4 503 15(gm./dte~) 4~8 4.9 4"8 ElongatioIl ~%) 28.3 30~5 28.9 CE ~%) 13.0 12"1~ ,7 CS (%) 16.6 15~ 17.~ .
Deni~r 15.6 15.6 15~5 dtex 17~3 17.3 17.2 Within the r~ge inve~tlgated, ~heathfcore wei~5~t r~tios }~ve l~ttle ef~ect on ya~ propertle~., For ho31ery ~llament~ with the ~heath at ~t~ thlnne~t pOillt be$ng about 1S~ o~ the filament diameter, m~ximum crimp frequency Ps obta~ed when the ~lla~ae~t comprises ~bout 50 60 p~rcent by ~eight core po:Lymer,, Crlmp frequency i~ not ~trongly dependent on percentage of` coreO Except at the lower extreme o~ the bperable level ~or percentage o:~ 6 nylon units irl the : .
core, ~llaments with 3û~70% b~ weight core polymer can provi de use~ul levels of crimpO

~ 41 -~7 ~.M~LE VII
This example ~ollows essentially the preparative method~ and u~es the same apparatus as Example II to com-pare 6~/6-12/6 nylon yarns and hose with e~uivalently prepared 6-12//6-12/6 and 6 6//6~12~6 ny;lon yarns ~d ho~e ~, The RV ' s of the polymers, measured a~ ple II, are:
6-12/6 43 ~ 1.5 ~65/35 weight ratio) 6-12 3~.5 ~ -5 6 40~,6 6--6 51n4 ~ 2~4 Melt temperature~ are 260 ~ 3C. for sp~ning fibers wlth 6-12 or 6 ~heath~ and 287 ~ 3C. for tho~e w~th 6-6 sheath~.
Meter pumps are adjusted to provide 60~ by volume of core polymer in each fllament which, by calculation, ylelds 58.7 59.0% by welg~ of core po:Lymer (is~ clo~e to a 40/60 ~heath/core welght ratio). Mono~ilament~ are ~pun, quenched, and stea~ conditioned, being plled to 2~ ment ya~s Just be~ore windup o~ the undra~ yarns at 500 ydO/
minO (45702 m./min,.), Croæs flow quench~ air 1~ 8Up-pl~ed at 49 ~ 1F. (9.4 ~ 0.5C~, ) . .
The spun 2-filam~nt yarns are ~ub~e~uentl~
~rawn UB.lng an unheated draw pln located between ~eed aJnd draw roll~. Draw ratio i8 4.225X at a draw-roll speed o~
~90 ydO/min. l~e drawn ya~n~ are immedl~tely packaged u~lng a ring-~d-traveler ~rindup which inserts 0~335 t;UI'n9 o~ twl~t per ~ch (00132 turn~m~,). Yarn propert~e~ :
~bta~ed are ~hown ~n Table l9o Nosiery are knitted ~d tested a~ d~cribed in }~ca~ple :I:V except that the load applied ~or HS and ~R
det~ ml~tion~ :La 2.77 ~, rather than 2027 kgs~ The - 42 ~

6~

drawn-only yarns o~ ~xampl~ IV are nominally 16-denlerg whereas the yarns of thi~ example are nom~nally 20~denierO
The ad~ustment in load i~ proport~onal to the di~erence in yarn denierO Characterl~ations of -the hoqe are pre~ented in Table 20.
~ xcept for the out o~-ho~e mea~ured pr~pertles of Table 20S all reeorded mea~urement~ are aver~ge~ of samples from twelve y~rn packages for the 6 nylon ~heath specle~ and from ~ix yarn packages for the 6-6 and 6-12 nylon sheath specieæ. Out-o~hose propertie~ are me~sured ~or ~our ho~e of the 6 nylon shea-th ~arns and ~or two ho~e each of the yarn~ with 6-6 and 6-12 nylon ~heaths~
It is apparent fro~n Tabl~ 20 thatJ although the hose of yarns wlth 6-12 nylon sheaths are ~uperior, all three species provide excellent stretch propertie~

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Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A crimpable, non-precrimped nylon fiber in filament or staple-fiber form, suitable for making into fabric without precrimping and for being crimped thereafter, consisting essentially of two, continuous, adherent, eccentric components, one component being a sheath consisting essentially of a homopolymer selected from the group consisting of polyhexamethylene dodecanedioamide, polyhexamethylene adipamide, and poly-.epsilon.-caproamide, the other component being a core consist-ing essentially of a random copolymer of hexamethylene dodecane-dioamide and .epsilon.-caproamide units, said copolymer containing about 25-45% by weight of .epsilon.-caproamide units.

2. The fiber of claim 1, said copolymer con-taining about 35% by weight of .epsilon.-caproamide units.

3. A fabric from yarn comprised of fiber as defined in claim 1 or 2.

4. A fabric from yarn comprised of fiber as defined in claim 1 or 2, said yarn having been made into said fabric without precrimping and subsequently having been crimped.

5. The fiber of claim 1 or 2, wherein said sheath consists essentially of polyhexamethylene dodecanedioamide.

6. The fiber of claim 1 or 2, wherein said sheath consists essentially of polyhexamethylene adipamide.

7. The fiber of claim 1 or 2, wherein said sheath consists essentially of poly-.epsilon.-caproamide.

8. The fiber of claim 1 or 2, wherein said core is 30-70% by weight of the fiber.