CA1235868A - Easily splittable self-texturing conjugate yarn - Google Patents

Abstract

EASILY SPLITTABLE SELF-TEXTURING CONJUGATE YARN
ABSTRACT OF THE DISCLOSURE
An easily splittable deep-dyeing conjugate filament is melt-spun by merging molten sub-streams of incompatible polymers outside the spinnaret to form a combined stream, then quenching the combined stream to form the conjugate filament. The filament is preferably drawn prior to winding, increasing the crimp level and increasing the dye stability of the filament.

Description

-1- 14-~4(8091) EASILY SPLITTABLE SELF-T~XTURING CONJUGA~E YAR~I
=
SPECI~ICATION
The inv0ntion relate~ to the ~rt of melt-spinning splittable conjugate filaments. More particularly it relates to ~plnning filaments which are more readily splittable and ~hich have improved dyeing propertie~.
It 19 kno~n to spin ~plittable conjugate filament~ by merging side-by-side a plurality of sub-~tream~ of incompatible polymer~ into a combined orconjugated stream within the ~pinneret9 the combined stream flo~ing along the spinneret capillary for several thou3andth3 of an inch, e.~., 0.012 inch (0.305 mm.).
The combinsd ~tream is then quenched to form a ~pun conjugate filament. The 8pun conjugate filament i 8 then typically hot drawn or draw-textured. The resulting drawn conjugate filament can be vigorously treated ~ith chemicsls or mechanically worked, or both, 90 as to split the conjugate filament into sub-filaments, each of which is composed o~ one of the incompatible polymers.
Typical references in this area are ~anner U. S.
3,181,224, Tann~r U. S. 3,418,200, and Ni~hida U. S.
. 4,073,988. The required vigorou0ness of treatment of the filamont (or of a fabric containing the filament) is disadvantageou 9 because the hot drawing step reduces the dyesbility of the filament, becau~e of the added cost of the step of working th~ fabric, and because of po~sible damaga to the fabric. If chemical treatment is involved, there i8 1093 of fiber polymer in ~ome cases and the added problem of disposal and handling of the chemical 8 involved 80 a 3 to avoid environmental pollution.
hccording to the invantion, these and other disadvantage3 in the prior art are avoided by a novel ~odification of the 3pinning process providin~ an ~z~

-2- 14-54(8091~

improved yarn with increa~ed productivity and reduced manufacturing cost.
According to a first principal aspect of the invention, there i~ provided a process for melt-~pinning an easily splittable deep-dyeing conjugate filament from flrst and Recond incompatible polymers, the yarn being self te~turing in fabric ~orm, comprising ~enerating a first molten sub-stream of the first polymer and a second molten sub-3tream of the ~econd polymer converging at substantially the s~ma apeed to merga ~ide-by-side as a combined stream below thç face of a spinneret, quenching the combined ~tream to form a con~ugat~ filament compri~ing a first sub filament of the first polymer lightly conjugated side-by-~ide ~ith a ~econd sub-filament of the second polymer, ~ithdrawing the filament from the combined stream at a predetermined spinning spesd, and winding the filament at a given ~inding speed on a bobbin, the polymers and the spin~ing speed being selected such that the filament on the bobbin splits substantially completely into the ~ub-filaments upon exposure to boiling water while under no tension. ~he first sub-~tream is preferably a polyamide (preferably nylon 66) and the second ~ub-stre~m is preferably a polye~ter (preferably poly( thylene terephthalate)). The spinning speed i3 advantageously at lea~t 2200 MPM and the filament shrinkage i9 prefer&bly at least 10% (advantageously at least 20%). Preferably the filament i~ drawn prior to being wound on the bobbin. Th0 winding ~pead and the amount by which the filament i9 drawn ars adv~ntagaously selected ~uch that the filament wound on tha bobbin has an elongation less than 70%, with be~t re~ults being obtained when the ~indinB speed and the amount by ~hich the filament is drawn are selected such that the fila~ent ~ound on the bobbin haq an elongation less than 50%.

~2~i~

-3- 14-54(80g1) According to a second principal aspect of ths inventlon, there i~ provided a yarn package haYing ~ound thereon a substantially constant denier deep-dyeing conjugRte filament comprising thermopla9tic incom~atible sub-filaments temporarlly adherln~ ~ide-by-3ide alon~
the length o~ the conju~ate filament, the Adhesion betwesn the sub-filAments being 3ufficiently light that the conju~ate filament splits sub3tantial1y completely into the sub-filaments upon exposure to boiling ~ater while under no tension. One of the 3ub-filaments i~
prefarably nylon 66 and the other of the sub-filament~
i 3 preferably poly(ethylene terephthalate). The filament preferably ha~ a ~hrinka~e greater than 10%, and advantageou~ly the shrinkage i9 greater than 20%.
The filament preferably has an elongation less than 70%, and especially preferred i~ an elongation less than 50g.
According to a third principal aspect of the inventiGn, there i8 provided a proce~s for melt spinning an easily splittable deep-dyein~ conjugste filament from ~irst and second incompatible polymers, the yarn being self-texturing in fabric form, comprising generating a first molten sub-stream of the first polymer and a aacond ~olten sub-stream oY the ~econd polymer converging at substantially different speed 9 to merge side-by-side as a combined 3tream below the face of a ~pinneret whereby an oscillation of the sub-streams occurs just below the face of the spinneret, quenching the combined stream to form a conjugate filament comprising a firat sub-filament of the first polymer liæhtly conjugated ~lde-by-6ide ~ith a ~econd ~ub-filament of the second polymer, withdrawing the filament from the combined st~eam at a predetermined spinnin~ speed, a~d winding the filament at a eiven ~inding speed on a bobbin, the polymer and the spinning speed being selected such that the filament on the .
. ,~

~235~
_~_ 14-54(8091) bobbin split~ substantially completely into the ~ub-filal~ents upon exposure to boiling ~ater while under no tension. The fir~t sub-stream is preferably a polyamide (preferably nylon 66) and the second ~ub-stream i 8 preferably a polye~ter (prefer~bly poly(ethylene terephthalate)). The spinning speed is advantageously at least 2200 MPM and preferably the filament ~hrinkage i~ ~raater than 1Q% (advantageously greater than 20%)o The filamsnt i9 preferably draw~
prior to being ~ound on the bobbin. The ~inding speed . and the amount by which the filament is drawn are advantageously selected such that the filament wound on the bobbin has an elongation less than 70d, with best re~ults being obt~ined when the winding speed and th~
amount by ~hich the filament i~ dra~n are selected such that the filament wound on the bobbin has an elongation le~ than 50~.
According to a fourth principal aspect of the invention, there is provided a yarn package having ~ound thereon a substantially variable denier deep-dyein3 conju~ate filamant comp~ising thermoplastic incom~atiblesub-filaments temporarily adhering 3ide-by-side along the length of th~ conjugate filament, the adhesion between the sub-filaments being ~ufficiently light that the conjugate filament splits ~ubstantially completely into the sub-filament~ upon exposure to boilin3 water while under no tension. One of the ~ub-filament~ is preferably nylon 66 and the other of the sub-filaments i~ preferably poly(ethylene terephthalate~. The filament prefarably has a shrlnkage greater thAn tO%, and advantageously the ~hrinkaBe i B greater than 20%.
The ~ilPment preferably hae an elon~ation less than 7Q%, and e~pecially preferred i8 an eloneation le99 than 50%.
Other a~pects will in part appear hereinafter and ~ill in part bo obvious from the Iollowing detailed de~cription taken together ~ith the accompanyine draw-ing, ~herein:

~35)~

-5- 14-54(8091) ~ I~UR~ a vertical elevational schematic of a ~pinnine app~ratus u~able according to the invention;
FIGU~B 2 i~ a graph qualitativaly ahowing ho~
tha ~hrinkage of PET and nylon 66 Yary ~ith spinning spesd;
FI¢U~ a vertical sectional view o~ a epinneret showing a co~bined ori~ice according to certain aspects of the invention;
~ I~U~ 4 i 8 a bottom plan vieu of the ~IGUR~ 3 ~pinneret;
J~GU~ 5 i8 a ~ectio~al view of a ~ ent according to the i~vention;
FIGURE 6 is a ~hematic eleYation view 3howing the oscillAtion o~ the molten streams ~U9t below the face of the ~pinnaret; and FIGURE 7 i~ a graph ~howing qualitatively the oscillation frequencies of a plurality of combined ~rifice 8 in the ~ame spinneret.
A~ shown in FIGUR~S 1, 3, 4, and 6, fir~t and second polymers are con~ugately melt spun as molt~n stream~ from ~pinncret 20. Molten ~treams 22 are quenched into filaments 24 by tran varsa quench air in quench ch~mber 26. The fil~ment~ are converged into yarn 27, w$th conventional ~pin fini~h applied at 28, the filhment~ being ~ithdra~n from tha molta~ atre~ms at a ~pinning spaed detarmined by unheatsd godet 30. The yarn ne2t pa 88e ~ over unhaated godet 32 prior to being ~ound onto a package by winder ~4. Godet 32 preferably i~ driven ~t laa~t ~lightly fa~ter tha~ godet 30, and it i 8 particularly ~referrad that ~od~t 32 be dri~sn at a ~ignificantly hi~her ~peed qo as to apply a dra~ to the filament~. The fila~ents may be entangled by conventional tangle chamber 36. While godets are praferred, godetle~s spinning i~ in accord with certain a~pect~ of the i~ventio~, in ~hich case the spinning 3paed ~ill b~ determined by the winder. It i~ preferrad that the ~odst~ be unheated $f god~t~ ara usad.

-6~ 54(8091) As sho~n in PIOUR~S 3 a~d ~, the prefs~red spinneret construction haa counterbores ~a and 40 formed in the upper sur~ace of spinneret 20. Capillar~ ~2 ~xtends ~rom the botto~ of co~nterbore ~8 to bottom Pace 44 o~ spi~nerst 20, ~hile oapillar~ 46 extends frs~ th~
bottom of counterbora 40 to faoe 4~. Capillarles 42 and ~6 are ~eparated by land ~8 on ~ace 4~,and their a~e8 form an included angle 80 that the molten polymer ~tream~ metered therethrough converge to merge Qide-by-side belo~ spinnaret face ~ a~ a comblnsd ~tream. The combined ~treRm i8 conventionally quenched (as b7 tran ~er~ely moving air) into a conjugate fllament which i3 ~ithdrawn ~rom the combined stream at the predeter-mined spinning speed set by godet ~0. The ~pinning ~pe0d i~ muoh highar than the speed of any o~ the ~olten sub-stream~, 80 that tha co~bin~d str~sm i8 attenuatad ~ubstantially aa it i~ bein~ quenched. Since the psir o~ capillarie~ 42 and 46 coop~ratc to form a si~gle combined stream, and ultimately a single Pilament, they are collectively referr~d ~o herein as a combined oriPice.
E~AMPL~ I
This i 8 an e~smple ~herein the yarn ha 8 constant deniqr. A 3pin~eret i~ provided contsinin~ 18 ¢ombined orifice~, each combined orifice being as di~clo~ed in thls e~ample. Thu~ the 0pinneret produces t8 eonJugate ~ilaments. Wlthin each combined orifice, cspillarics 42 a~d ~6 have dia~etcrQ of 0.009 inch (0.23 m~.) and ar~ 0.1 inch lon~ (2.54 amO). Ths a~is of each capillary i9 incllned 12 Prom the vertical, and thus the ase~ ~ithin a combined orifico Por~ an included a~gl~ o~ 24. Land ~3 saparatlng capillarie~ 42 and 46 on f~ce ~4 ha~ a ~ldth o~ Q.017 inGh ~0.4~ mm.).
Whil~ thic paragraph ~or ~implicity refers only to ~pinning of a ~in~l~ filament from a single ~æ~s~
-7- 14-54(80gt) com~ined orifice, it ~ill be undar~tood that the ~s~e de~cription applie~ to each o~ the sther combined orifice~ in the spinneret. Moltan nylon 66 polymer of normal ~olacular ~eight for appsrel end use i 3 meterod and e~truded as a ~irst ~ub-~tream through capillary 42, whlle molt0n poly(ethylene ter2phthalate) polgmer of normal ~olecular weight for apparel end uae 1~ metered through capillary 4S to form a 02cond sub-~trea~. The polymer melt temperatures are 285C. Tha resultine combinad ~traa~ $8 con~entionally quenched into a oon~ugate filament by transYersely directed air havin~
an avsrage speed of about 15~20 meters per minute, and the filament i8 withdra~n from the co~bined stream at a ~pinning speed oP 3795 meter~ per minute (MPM). The pol~mer meterinB rata 8 are ~elected such that equal volumes Or polymer are extruded through capillarie~ 42 and 46 per unit o~ time, and ~uch that ths conjugate fila~ent ha~ a denier of 3.87. A con~entional spin-finish i8 applied prior to ~indine at normal ~inding tension of about 0.1 gram per denier. The multi-~ilament conjugate ~arn thu~ produced according to the invention comprlseo ther~opla~tic (nylon and polyester) sub-~ilaments temporarily adhering ~ide-by side along the length of the Qon~u~Ate filamento. ~he adhesion bet~een ~ub-~ile~ent~ i8 ~uf~icient that the filament (or ~ yarn compri~in~ a plurality of ~uch filaments) can be h~ndled normally in sueh oparations ao te~turing, knitting or weaving without difficulty, yat i 3 ~u~ficiently light or wesk as to readily be o~ercome ~h~n the conju~ate ~llament i8 e~posed to boiling ~ater, as i~ the nor~al scourine and dyelng operation~ employed i~ proGasoing o~ fabric~. Under ~uch condition3, the con~ugate fila~snt ~pontaneously and oubstRntially completely 3plit8 into it~ con~tituent ~ub-filaments, thu~ avoiding the n~e89ity for vigorou~ly working tha '~3~
-8- 14-54(80g1) ~abric to ~chieve splitting as is nece~ary with prior art oplittabls conjug~te filament~. Ordinarily no added ~tsp of working o~ the fabric i8 nece~sar~ ~ith Pilament~ and yarns accordlng to tha present invsntion.
The ~arn i8 woven as filling across a conventional warp9 then con~entionally scoured and dyed at the boil. The filling filaments split substantially completely into their constituent sub-filament3 spontaneously upon contact ~ith the boiling water with the PET sub-filament~ ~hrinking most and forcing the nylon 3ub-filsment3 to protrude from the 2urface of the fabric in loopa or arches. The fabric dyes more deepl~
than fabrics made from yarn~ which have been hot dra~n.
A po~sible partial explanation for the unusual behavior of the yarns of the invention may be had with reference to FIaUR~ 2 of the dra~inB. As generally ~ho~n therein, the shrinkage of a 100% PET yarn falls rapidly from ~ery high value 8 of about 50-70% at intermediate spinning ~peeds to value 8 below 10% over a fairly narro~ range of somewhat higher spinnine speeds, while the shrinkage of nylon 66 does not exhibit such behavior. ~he e~act spinning speed range in which polyester yarn e~hibits the l~rge change in shrink&ge ~ith 0pinning speed ~ill vary Nith capillary diameter (jet stretch). Yarn~ according to the invention may be made to be ~elf-texturing i~ fabric form by selection o~
the spinning speed such that the PET sub-filament has subotantially higher ~hrinkage than the nylon 66 ~ub-fila~ent, a~ in the E~ample I yarn aboYe. When such yarns are put in fabrie ~orm, then subjected to the cuatomary 3courin3 and dyeing operations, the filaments Rplit into th2ir constituent sub-filament~ ~ith the PET
~ubfilame~t~ then shrinking sub~tantially more than ths nylon subfilament~. This forces the nylon subfilaments to th~ Rurface of the fabrio in protrudin~ arches or 3~
-9- 14-54t8091) loop~, eiving tsxture to the fabric. When the filaments have ~ub~tantially con~tant denier as in Example~ I and II herein, be~t ~elf-texturing effects are obtainad ~h~n the yarn ~n the bobbin has a shrinkage of at least 10%, preferably at lea~t 20%.
Additional runs are made at different ~pinning cpeeds with the polymer metering rates adjusted to provide about 40 yarn denier, with re~ult~ as follo~a.

__ Godet ~0 Godet ~2 Elongation, Shrinkaee~
Item MP~ MPM % %
~700 3700 94 48 lS 4 ~500 4500 73 9 ~ he re~ulting yarn~ are woven as filling across oonventional warps, with the re~ulting fabrics conventio~ally ~coured and dyed at the boil. The filAments ~plit 3ubstanti~11y completely into the ~ub-filaments and pro~ide pleaeing texture to the fabrice. Ho~ever, the fabric from Item 4 ha~ noticeably less texture than the fabric~ from the other items.
E~am~le II
A series of runs are made using the same ~pinneret and polymar~. Tha poly~er m~tering rate 8 arg reduced to produce sbout 40 yarn danier (about 2.2 d~nier p~r filament) ~hile ~aintaininB equal Yolume~ of nylon and polye~ter. In each run, the actual ~indin~ speed i~
slightly lower than the ~peed o~ godet 32 in order to ad~ust the ~inding ten~ion to about 0.1 gram per denier.
Godet speeds and yarn propertie~ are a ~ 8et forth in T~ble 2.

~L%;~ 8 -10- 14-54(8091) TA~LE 2 Godet 32, Godet ~0, Elongation, Shrinkage, Item MP~ ~P~ _% %
1 400~ 36~0 76 53 3 ~500 3600 66 5~

6 4500 3000 5~ 62 lO 7 5000 3600 48 51 9. 5000 3200 49 55 5000 ~000 ~5 ~6 The yarn~ of Table 2 are sup~rior to that of Example I above, particularly in term~ of dye-fa3tnes~ of the nylon co~ponent with respect to di~perse dye~. A
~mall amount of dra~ in conjunction with high Qpeed spinning i~ highly desirable in this regard. Within the ~able 2 yarns, item~ 5 and 6 are more desirAble than lte~ 4, ~hile items 7-10 are still further improved.
Superior re 8ul t 8 are obtained when a ~mall amount of in-line dra~ i 9 applied a~ in this example. It i~ b0lieved that the more viscous PET ~ub-atream bears most of the stress of the high speed spinnine, pr~venting 25 the nylon ~ub-stream fro~ receiving ~ufficient RtresQ for proper orientation of the molecules if the solidifisd ~ nt i9 not dr~n prior to winding. After the filament has solidiflsd, ho~ever, a ~mall amount o~ dra~
appliod be~ore ~indin~ orients the nylon enough ~or dye-faAtne~. It ia ~urther believad that if the ~pin~in~ speed ~sre su~ficiently hi~h that the yarn would havo a shrinkage b~low 10% or 80, a ~mall a~aunt o~ dra~
~ould increa~e tha PET shrinkage ~hile not greatly affecting that of the nylon~ thus providing the large 35 shrinkage difference bet~een the nylon and polyester ~3S~;8 -11- 14-54(8091) components necessary for the self-te~turing effect in fabric form.
EXAMP~E III
.
In contrA~t to the constant denier filsments produced in E~ample I snd II, a variable denier fil~ment i3 readily produced by merging sub-streams e~truded at aubstantially di~ferent speed~, producing an oscillation o~ tha sub-stream~ just below t~e spinneret. ~hi~ i~
preferably done by use of the ~ICUR~S 3 and 4 type of combined orifice. The axes of capillaries 42 and 46 are each lnclined 4 from the verticalO The axe3 thus form a~ included angle of 8 , and capillaries 42 and 46 are separated by land 48 o~ face 44. Capillary 42 haa a diameter of 0.009 inch (0.23 mm~) and a length of 0.032 inch (0.81 mm.) while capillary 46 has a diameter of 0.016 inch (0.41 mm.) and a leneth of 0.146 inch (3.71 mm.). Land 48 has a ~idth Or 0.004 inch (0.1 mm.).
The sAme polymer~ are u~ed as in Example I
abo~e, and the spinneret contains 18 combined orifice as described in the preceding paragraph. The polymer temperatures are each 282C~, ~ith the polyester being e~truded through cApillarie 8 42 and the nylon throu~h capillaries 46. The metering rates are sel~cted ~uch that the polyester/nylon ratio is 60/40 by volu~eg and the resulting 18 filament yarn has a total denier of 41.1. The ~pinning speed is 3658 ~PN and the molten stream~ are quenched and ginished prior to ~inding, as in E~ampla I.
~he yarn i~ woven aR filling across ~
con~entional warp, then conventionally ~coured and dyed Rt the boil. The filling rilaments split ~ubstantially completely into their con~tituent ~ub-rilaments spont~sneously upon contact with the boiling ~ater and provide fabric te~ture, a~ do the filaments in E~ample I
above. Again, the polyester sub-filament has the higher :~3~
-12- 14-54(8091) ~hrinkage, forcing the nylon sub-filaments to the surface of the y~rn. Yarn3 accordine to thi~ example give in ~abric form various noYelty sffects not svailable ~ith tha Exa~ple I yarn~ A~ ~ith the Example II yarn aboYe, an ln-line dra~ (prior to winding) i~ exp0ct~d to lncrease the crimp level and improve the dye atability of the nylon sub-filaments to disper~e dyes.
Yarn shrinkage i8 determined by tha followin~
method. The bobbin i~ conditioned at 21 C and 65%
relative humidity for one day prior to te~ting. 100 meters of surfac2 yarn are atripped off and discarded.
Using a Suter denier reel or equivalent, the yarn i 3 wound to form a skein having about 18,000 sksin denier.
Thst is, tha denier reel revolutions are 9000 divided by the yarn denier. The ~ein yarn end B are tied together.
Ths skein i~ s~spended from a rod having a diameter of one centimet~r and a 1000 gram ~eight i~ attached to the bottom of the ~kein. After 30 aeconds, the skein length is measured to provide length Ll. The 1000 gram weight i~ then r~placed by a 50 gram ~eight, whereupon the rod with s~ein and 50 gram wei~ht are placed in a vigorously boiling ~ater bath sufficiently deep that the skein i8 unde~ tension from the 50 gram weight. After 10 minutes in the boiling ~ater bath, the rod ~ith qkein and the 50 gram Neight ars removed from the bath and hung up for three minutes to pe~mit excess ~ater to drain off. Tha rod ~ith ~kein and s~spended 50 gram ~eight are then piaoed in a 120C oven for 15 minutes, after ~hich the rod ~ith ~kein and suapanded 50 gram weight are removed from the oven and hung for 15 minutes at room temperature. The ~uspanded 50 gram weieht 1~ then removed and replaced by a 1000 ~ram ~ight. Aftsr 30 ~cond~, the skein length i8 i9 measured to provide L2.
~he % ~hrinkaga i~ defined a8 lOO(Ll - L2) di~ided by Ll.

3L2;~ 8 -1~- 14-54(8091~

By "incompatible polymers" io meant that the polymer~ ar~ chemically dis~imilar, as in the e~emplified polyester and nylon~
The precise reason for the uneYpected incrsased es~e of splitting of the filaments of the inYention ~8 compared to prior art splittable filaments is unkno~n.

Claims (34)

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

1. A process for melt-spinning an easily splittable deep-dyeing conjugate filament from first and second incompatible polymers, said filament being self-texturing in fabric form, comprising:
a. generating a first molten sub-stream of said first polymer and a second molten sub-stream of said second polymer converging at substantially the same speed to merge side-by-side as a combined stream below the face of a spinneret;
b. quenching said combined stream to form a conjugate filament comprising a first sub-filament of said first polymer lightly conjugated side-by-side with a second sub-filament of said second polymer;
c. withdrawing said filament from said combined stream at a predetermined spinning speed; and d. winding said filament at a given winding speed on a bobbin;
e. said polymers and said spinning speed being selected such that said filament on said bobbin splits substantially completely into said sub-filaments upon exposure to boiling water while under no tension.

2. The process defined in claim 1, wherein said spinning speed is selected such that said filament has a shrinkage of at least 10%.

3. The process defined in claim 1, wherein said spinning speed is selected such that said filament has a shrinkage of at least 20%.

4. The process defined in claim 1, wherein said first sub-stream is a polyamide and said second sub-stream is a polyester.

5. The process defined in claim 4, wherein said first sub-stream is nylon 66 and said second sub-stream is poly(ethylene terephthalate).

6. The process defined in claim 5, wherein said spinning speed is at least 2200 MPM.

7. The process defined in claim 6, wherein said filament is drawn prior to being wound on said bobbin.

8. The process defined in claim 7, wherein the amount by which said filament is drawn is selected such that said filament has a shrinkage greater than 10%.

9. The process defined in claim 7, wherein the amount by which said filament is drawn is selected such that said filament has a shrinkage greater than 20%.

10. The process defined in claim 7, wherein said winding speed and the amount by which said filament is drawn are selected such that said filament wound on said bobbin has an elongation less than 70%.

11. The process defined in claim 7, wherein said winding speed and the amount by which said filament is drawn are selected such that said filament wound on said bobbin has an elongation less than 50%.

12. A yarn package having wound thereon a substantially constant denier deep-dyeing conjugate filament comprising thermoplastic incompatible sub-filaments temporarily adhering side-by-side along the length of said conjugate filament, the adhesion between said sub-filaments being sufficiently light that said conjugate filament splits substantially completely into said sub-filaments upon exposure to boiling water while under no -tension.

13. The package defined in claim 12, wherein one of said sub-filaments is nylon 66 and the other of said sub-filaments is poly(ethylene terephthalate).

14. The package defined in claim 13, wherein said filament has an elongation less than 70%.

15. The package defined in claim 13, wherein said filament has an elongation less than 50%

16. The package defined in claim 13, wherein said filament ha 8 a shrinkage greater than 10%.

17. The package defined in claim 13, wherein said filament has a shrinkage greater than 20%.

18. A process for melt-spinning an easily splittable conjugate deep-dyeing filament from first and second incompatible polymers, said filament being self-texturing is fabric form, comprising:
a. generating a first molten sub-stream of said first polymer and a second molten sub-stream of said second polymer converging at substantially different speeds to merge side-by-side as a combined stream below the face of a spinneret whereby an oscillation of said sub-streams occurs just below the face of said spinneret;
b. quenching said combined stream to form a conjugate filament comprising a first sub-filament of said first polymer lightly conjugated side-by-side with a second sub-filament of said second polymer;
c. withdrawing said filament from said combined stream at a predetermined spinning speed; and d. winding said filament at a given winding speed on a bobbin;
e said polymers and said spinning speed being selected such that said filament on said bobbin splits substantially completely into said sub-filaments upon exposure to bailing water while under no tension.

19. The process defined in claim 18, wherein said spinning speed is selected such that said filament has a shrinkage of at least 10%.

20. The process defined in claim 18, wherein aid spinning speed is selected such that said filament has a shrinkage of at least 20%.

21. The process defined in claim 18, wherein said first sub-stream is a polyamide and said second sub-stream is a polyester.

22. The process defined in claim 21, wherein said first sub-stream is nylon 66 and said second sub-stream is poly(ethylene terephthalate).

23. The process defined in claim 22, wherein said spinning speed is at least 2200 MPM.

24. The process defined in claim 23, wherein said filament is drawn prior to being wound on said bobbin.

25. The process defined in claim 24, wherein the amount by which said filament is drawn is selected such that said filament has a shrinkage greater than 10%.

26. The process defined in claim 24, wherein the amount by which said filament is drawn is selected such that said filament has a shrinkage greater than 20%.

27. The process defined in claim 24, wherein said winding speed and the amount by which said filament is drawn are selected such that said filament wound on said bobbin has an elongation less than 70%.

28. The process defined in claim 24, wherein said winding speed and the amount by which said filament is drawn are selected such that said filament wound on said bobbin has an elongation less than 50%.

29. A yarn package having wound thereon a substantially variable denier deep-dyeing conjugate filament comprising thermoplastic incompatible sub-filaments temporarily adhering side-by-side along the length of said conjugate filament, the adhesion between said sub-filaments being sufficiently light that said conjugate filament splits substantially completely into said sub-filaments upon exposure to boiling water while under no tension.

30. The package defined in claim 29, wherein one of said sub-filaments is nylon 66 and the other of said sub-filaments is poly(ethylene terephthalate).

31. The package defined in claim 30, wherein said filament has an elongation less than 70%.

32. The package defined in claim 30, wherein said filament has an elongation less than 50%.

33. The package defined in claim 30, wherein said filament has a shrinkage greater than 10%.

34. The package defined in claim 30, wherein said filament has a shrinkage greater than 20%.