CA1319502C - Fiber creel humidification - Google Patents

Abstract

Abstract of the Disclosure A process and apparatus for supplying never-dried yarns from a humidified creel to maintain a constant and controlled amount of moisture on the yarns and, thereby, assure that the supplied yarns are maintained at a constant quality for further processing.

Description

l3~a~

K~-297 5 Title F~ber Creel Humidiicat~on Field of the ~nvention This invention relates to a method and apparatus for maintaining controlled moisture content on wet, never-dried, fibers prior to further proce~ng steps. ay this invention, never-dried fibers ean be supplied from creel storage and ~ub~ected to continued treatments which require the u~e of wet feed yarn6. In thi~ lnvention, fibers ~re kept on spool~ or oth~r package6 ln a cre~l enclo~uee with controll~d humldity ~waitlnq further p~oce~sing and thi~ invention relate~
to ma~ntaining a controlled humldity in the enclosure.
1~
B~ckground and Prlor Art Wet-~pun yarn~ or other yarn~ requ~ring controlled heat trentment or immersion in varlou6 treating b~ths are often requ~red to have ~ c~rt~n, contro~led, ~fflount of ~oi~ture lncluded th~reln prlor to the tre~tment. The f~ed or s~ch y~rn~ h~ o~ten been pro~id2d from l~er~ion in w~ter but 6ueh ~s ou~ber~om~
and often l~d~ to lnconsi~t~nt r~6ul~s due ~o water carrlod on th~ ~xtor~or of th~ y~rn ll~nt~. -Th0 ~d ~or 6uch y~rn~ can, o cour~o, be provlded on-line ~ro~ 6plnnlng ~nu~ctur~ but, becau60 the 6ubs~qu~nt tr~at~nt~ are n~arly ~lw~ys ~uch 610wer t~n ~he 6p~nn~ng proces6/ on-lln~ wet y~rn 6upply cau~e6 ~ 6erlous fiber production bottleneck.
~or ~o~e appllcatlons ln the pa~t, ~ ore~l ~or holdlng and ~upplying y~rn6 from sev~ral yarn spool ~ource~ wa6 us~d. ~efore the pre~en~ ~nv~ntion, however~ cre~l6 could no~ succ~ss~ully bo u~d ~o ~upply wet yarns b~caus~ the æmount of ~oi~ur~ on the supply yarns was not ~on6tant ~nd ~hat l~d to lnt~rrupt~d proce6~ oper~tlon And incon6~t~nt p~oduot qualltl~æ.

~ 3 ~

For optimu~ operation of ~uch tre~tment6 u~ing wet yarn 6upplled from creel6, the yarn ln the creel ~u6t be ma~nt~ned at a constant, controlled, ~016ture level.
~n the manufacture and/or ~ub~equent proces~ing of 60me yarn~, it i~ neces6~ry to control the mo~stur~ content of the yarn ~MOY - Mo~ture On Yarn) to within ~ cert~in range. An example of ~uch ~ process Is the manufaeture of precur~or yarn~ to make high modulu6 para-aramld yarns ~uch a6 those d~ficlo~ed in European Patent Appllcation 247889, publl6hed December 2, 1987.
In the ~anufacture of 6uch yarn~, w~ter-swollen precur60r y~rns ~re sub~ected to heat t~e~tment under ten6ion to lncr~6e the modulu6 and ~a$ntaln a hlgh tenac~ty in the flni~hed yarn. ~he ~axi-mum benefi~s of a proces~ such as the one of that European Patent ~ppllcation are obtained when the y~rn6 are ~never-drled~, that 15, when they are ~lnt~lned at a conteolled, relatively hiyh, ~oi~ture content after splnnlng and prior to be~ng ~ub~ected ~o furth~r treat~ent. Another exa~ple of ~ proce~s where ~ certaln ~016ture content in wet ~eed yarn 1~ iaport~nt i6 a proces6 whereln yarn~ ~r~ colored or tr~ d by an imblbl~lon proces6 6uch a6 ~n Brlti6h Pat~nt 1,43~,067.
In 6uch ~ proce~6, ~t i6 d~ir~bl~ for pr~cursor yarn6 to have ~ c~rtaln, contrcll~d, MO~ b~for~ b~lng plae~d into ~he l~blhltlon bath; ~nd ln tha proc~e6 of th~t rcfèrence, the wct-~pun feed yarn~ ~r~ ~uppl~ed feo~
l~er610n.
Before the pre6~nt inventlon, ~n ~lber treat~nt operat~on6 6ub6equent ~o ~pooling of n~ver-deied ~lbers wher2 ~t~mp~ were ~de ~o ~upply flber from crQ~l~ situat~d ~n the open, ~blent, condltlon6 of the ~nufacturing ~aclllty, the r~ult6 were un~a~lsfae~ory. P~ckag~s or ~pool~ of 1ber which wcre ~oun~0d on the creel~ W~E~ ~ountod wl~h, genarslly, A prop~r and de6ircd MO~, bu~ durlng ~hs walt for 1319~

proce66 6tartup and durlng the r~ther lengthy operation of the proce6~, ~t6elf, moi~ture was 106t ~rom the 6ever~1 spool6 in unacceptably large amount6 and the moisture wa~ 105t ln ~n uneven way ~uc~ that the fiber treatment operation6 were conducted on flber~ which were too dry ~nd which were of varying moisture content.

Summar of ~he Invention ~he present invention provide6 a method and a controlled hum~dity creel apparatu6 for m~intaining a hlgh yarn moisture content during 6torage ~nd unwlnding comprl6ing ~ount$ng package6 of never-drled yarn in ~
creel on package 6uppor~ me~n6 comprl~ing a plùr~l~ty of 6plndl~6 areanqed for unwinding y~rn from s~d package~, maint~ining the atmo6phere surroundlng the p~ckage~ at a high hu~ldity, and providing a mean6 for unwlndlng yarn fro~ th~ package6 ln the high hu~ldity at~osphere, and 6ub6equently, re~oving the unwound y~rn ~rom that at~o6phere. The 6plndle~ are ~oun~d ln ~n enelosure ~ean6 ~or prov~dlng ~t le~t ~ partl~l ~nv~lope ~bout the ~plndle6 ~nd the packaqe~. Ther~ i~ prov~ded a hu~idlty controll~ng me2n6 oo~prlalng 9~ clrculat~on m2ans ~or e~rcul~lng ga6 through the ~nv~lope, moi6ture ~upply ~2an6 ~or supplylng ~olstur~ ~o ~h~ s~rcula~lng 9~8, hu~ldl~y m~a~ur~ment ~Ans for ~a6urlng th~
hu~id~ty of the 9~6 b~lng clrculatod, and con~rol ~an6 re~pon~lv~ to ~aid humid~ty ~a~ur~ent mean6 or ~ctuating 6aid ~oi~ture ~upply ~uns 6uch ~hat the at~ospher~ ~n6ide the ~nvelope and An contact wlth yarn ~oun~ed therein can be ~aln~in~d at a rel~vely high, controll~d, humldity.
It h~6 b~en discov~red tha~ th~ aoi6tur~ level of n~ver-drled yarn on pack~ga6 c~n ~e ~aln~lned by ~ain~a~nlng th~ y~rn in hlgh hu~idl~y conditlon6.

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Brle De6crl tlon of the Dr~w~n ~
P ~ q ~19. l lc a ~lmpllflad ~rpre6ent~tlon of the creel of thls invention~
Fig. 2 1~ a slmpllfied repre6entation of the humldlty controlllng m~ans o~ thl6 inventlon.
Flg. 3 is a ~implified repre~entat~on, in part~l section, of the humidlty center which includes moisture 6upply me~ns, hum~dity ~ea~urement means, and ~ontrol mean~.

Det~lled D~scrl~tlon __the Inventlon ~ferrlng now to the d~awlngc ln whlch llke or corre6pond~ng pa~t6 ~re de61gn~ted by llke ~efetence characters throughout the several view6, F~g. 1 ~epr~6ents a preerred ~pp~ra~u~ fo~ practlce of thl6 inventlon.
~nclo6ure lO h~6 ~ld~ ll and 12 ~hown to be tran6p~rent) ad~cent to packnge 6uppor~ ~e~ns ~nd hu~ldlty controlllng ~e~nc. ~n Flg. 1, there are ~hown supply plp~s 30 and ~turn plpe 31 f~o~ tho hu~ld~ty controlllng ~e~n~. P~ckage 6uppo~t ~e~n~ ln~lud~6 ~all6 16 for hold~ng eplndle6 17 on whlch at~ ~oun~ed packag~
18. pa~k~gafi ~8 A~ tho 8poolc or bob~ln6 or ~on~ or other pack~g~6 of n~r-d~l~d flb0r~ to b~ tro~d in ~hl6 lnv~ntlon. Moun~d on b~ 19 ~bov~ and no~r to ~plnd~ 17 ar~ ~k~-o~/ten~lonlng guld~ 20. ~n 21 f ro~ pack~ge~ lB 1~ r~ov~d ro~ ~n~106u~ 10 o~er gu~de~ 20. Th~r~ ean be ~or0 th~n on~ rall 16 ~- rwo ~re ~hown ln Fl~ and wh~n ~here ar~ two they ar~
qenorally p~rall~l or ~ount~d ln 8 ~ingle pl~aae ~t ~l~ght angl~. ~aeh ra~l 16 ~an h~ ~ a plu~allty o 6plndle6 ~ 7 ~nounted 6uch thst ys~n 21 cwt b~ r~ov~d ~lly th~r~fro~ and ~a~h y~rn 2~ 1$ gul~l~d ovor and pa6t gu~d~ 20 6uch ~h~t the yarn~ 21 ~r0 r~ov~d f ro~
enelo~ure 10 ~ a w~p 22.

13~9~2 Enclocure 10 (B5 well a~ ~ther ext~nded component p~t~ of Flg. 1) 15 6hown ~6 broken at the end6 because it can be of any, indef~nite, length. ~he purpose of enclo~ure lO ~s to contain a humid atmosphere ~nd en~lo~e lO can, therefore, al60 lnclude ends and a bottom and ~op, as well as ~lde~ ll and l~, lf such are deemed de6ir~ble a6 useful.
Referring to Fig. 2 and 3, the humidity controlling ~eans include~ gas circulation ~eans 23 with humidity cent~r 24. Humidity center 24 include~
mo~6tur~ supply mean~ 25, humldity ~ea6urement ~ean6 26, and control me~n6 27 ~o~nted ln operatlve relat1On thcreto. Gas clrculation mean~ 23 ~nclude~ 6eetlon6 28 and 29 each o~ whlch have two 6upply plpes 30 ~nd one return pipe 31. In operation, th~ hu~idlfled gas ln ga6 clrcul~tlon ~ean~ 23 i6 forced, by blower 32 ~ounted ln maln leg 33, through humldity cent~r 24, through dl~trlbu~on.tee 3~, and to manlfold6 35. The humldlfled ga~ lc thon conduc~od lnto ~upply p~pe6 30 and lnto ~he enclo~ure through p~r~or~t~ons tnot 6hown) ~n the surf~ce o~ ~upply plpe~ 30. Supply plpes 30 are preferably ~ount~d ~bove ~he pack~go 6uppor~ ~an~ and tho p~rforatlon~ ~re pre~er~bly ln ths bottoffl por~lon o~
~h~ ~urface of th~ p~pe6. G~ etu~n~d ro~ th~
~nolo~ure to ga~ clrcul~tlon ~n6 23 ~hcsugh p~rfor~tlon~ 36 ln th~ ~u~fa~ of ~oturn plp~8 31 ~turn plp~ Ar~ pr~g~rably ~ounto~ undsr th~ packa~
~uppor~ ~ean60 ~ha~ g~ ~6 d~awn tbrough ~aln leg~ 33 and pa6~ed lnto bumldlty ç~nt~ 2~. Sn ~u~ld~ty eenter 2~ e r~lat~e hu~ldley o ~h~ ga6 ~ d~t~lned by th~ hu~dl~y ~oa~u~m~nt ~ana 26 u~1ng, fo~ ox~mple, wat bulb an~ dry ~ulb t~mp~atu~ adlng~. ~n lndleatlon of th~ ~latlv~ hu~ldlty o ~ho 9~ nt to ~ontrol ~an~ 27 ~nd, lf th~ r~l~t~Y~ hu~ldl~y ~s lndleat~d to be 1~8~ eh~n ~ p~edo~o~n~d ~lnl~u~, wa~ç~
f~o~ llne 38 1B ~ondu~t~d to ~ol~ur~ ~upply ~n6 2S

~319~2 and i~ in~ected into main leg 33 to humldly the g~
In thi6 way, the atmo~phere ln the ~reel enclosure ~s maintained ~t a high, predetermined, rel~tive humldity.
It has been found that an effective and preerred means fo~ injecting mo~sture into main l~g 33, 16 to use an ultrasonlc mlst generator as moisture supply means 25.
Thi~ invention i~ directed e~pecially toward the u6e of para-aramid fibers, particul~rly poly(p-phenylene terephthalamide) ~PPD-T). PPD-T and fibers therefrom can be made ln accord~nc~ w~th Blade~, U.S. 3,a69,42g, ls~ued March 4, 1975. Other fiber6 can, of cour~, be u~ed ~n practice of thl~ lnvention; and, ~n fact, thi6 invention can be u6ed for any f~bers which must be fed to ~ proce6s in a form which requlres 60me controlled amount of molsture.
This lnven~ion is particularly u~eful in maint~ning ~016ture on yarn prlor to heat treatment.
One example of 6uch a heat tre~tment i6 di6closed in above-mentloned European Patent ~ppl~eatlon 247,~89.
In the pr~ctice of the proces~ dlsclosed 1 that ~uropean Pat~nt Appllcation, yarn wsu}d b~, customarily, ~upplied on packages to ~ cr~l havlng a NOY of abou~ 35~5~ water ~nd lt ha6 b~en d~6cov~rad that - that MOY c~n be malnt~ned if the relatlY~ hu~ldlty ~n ~5 the creel enclo6ure ~6 controlled to ~bou~ 90 to 99~ ~t a~bl~nt te~p~r~tura. Flow of the ~t~o~ph0r~ through the creel ~nclo~ure 1~ ~d~usted ~o m~lntain that hu~ld~ty at that te~p~rature.

3~ A6 a gen~ral rule in the treatment of never-dri~d y~rn~, lt 1~ preferred tha~ the yarn6 be kept at a MOY h~gher th~n that at wh~ch co~plete con60llda~10n of the poly~er ~truc~ure oecur~. It ~
generally belleved that the MOY 6hould b~ N~lnt~ined at gr~at~r ~han about 20%, ba~ed on dry weight o~ the yarn, for p-~ramld y~rn~.

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The atmo6phere in the creel ~, generally, air with water; but if de~red or requ~red for ~ome partlcular purpo6e, the air could be replaced by ~ome other ga~ such a6 nitro~en or argon or the like.
s De~cri tion of the Preferred æmbodiments P
Feed y~rn~ for the follow~ng example~ were made in accordance with the proeedures de6cribed in the abov2-ment~oned European Patent Appl~cation.
Three feed yarn~ of poly(p-phenylene terephthal~ide) were u6ed ~n the followlng example~.
A~-~pun properties of those yarn~ are provlded in Table 1, below.
TA~LE 1 Yarn Deniec Inh.Vis. Tenacity ~odulu6 # (q/dl) ~gpd~ (qpd?
A 400 5.5 26.5 550 B 1150 5.4 26.7 ~30 C 1~35 5.4 26.5 520 The fe~d yarn identified, ~bove, ~6 Yarn ~B
wa~ ~ub~ected to ~ h~at tr~at~ng proco~c ~ d~r~b~d ln the ~bove-~entloned ~uropean Pat~n~ Appllca~lon. A
warp co~po~d af 4~ ~nd6 o~ th~ y~rn w~ h~ e~O~t~d in a 40 foot ~12.2 ~t2r~ ov~n at 650~C, 135 yard p~r ~inut~ (123 ~ nd und~r t~n~ion of ~.2 gr~mc p~r den~er ~gpd). ~h0 yarn r~ldence t~a ln th0 ov~n W~6 ~bout 6 seeond6. The oY~n wa~ ~lectric~l~y h~at~d ~nd the yarn6 were heated pr~mar~ly by r~dl~nt h~at~ ~nd, only part~lly hy conveetive heat. The oven wa~
continuou61y purged w~h nltrogen preh~t~d to oven temper~ture. ~he y~rn l~avlng the oven w~ adv~n~d by a 6a~ o~ w~ter-cooled rolls on whlch the y~rn t~mperatur~ was r~duced to ~bout 25~C.

13~9~

The yarn6 6upplied for conduct of ~he heat treatment were positioned on the ~plndle~ of a creel of this invention and were maintained, before the heat treatment, in the humidi~ied creel of th~ invention in an ~tmosphere of air ~t a relative humldity of 90 to 99%. A~ a comparative test, feed yarns from the same splnn~ng run were heat treated as 6upplied from an unhumldified c~eel.
As an indication of the improvement provided by the pre6ent invention, it wa~ noted that the yarn~
6upplied f~om the unhumidified cceel were non-uniform ~n color along the l~ngth, v~rying ro~ d~rk gold to dark brown lndic~ting varlable deco~po~tlon ~nd non-uniform yarn properties, while the yarns 6upplied from the humidif~ed creel of this invention remained uniformly dack gold ln color.
A ma~or benefit provided by the pre6ent lnvention re6ides in the decreased yarn bre~k~ge wh~ch occur6 during the 6ub6equent yarn ~reat~ent when ~hi~
inven~lon ~s used on ehe feed yArn6. In sub~equent tre~t~ent6, the packages 0$ nev~r-dried y~rn6 m~y be ~ount~d on the cre~l for 6 or a~ long ~ 8 hours unt~l co~pl3tlon of the tr2at~ent. Dur~ng th~t tl~e, there 16 6~riouB lo~c of ~ol~ture and incr~a~e ln y~rn b~o~age without the benefit of thl~ lnv2ntion. Count~
of rem~lnlng, unbrok0n, yarn6 (endst w~re ~ad~ or sev~ral run6 ~at l~ast ~n run6 ln ~11 c~6e6) of the creel 6et-up~ of 4B y~rn~; both; wl~h the hum~dlfied creel of thl~ ~nv~ntionl ~nd wlth the unhu~idified creel. R~ult~ of tho6e count6 are pre~ented ln Table 2, b~low.

~3~ ~5~%

Creel Ends at Ends in Ends in Color at Set-up Start 2 Hrs. 4 Hrs. 2 Hrs.
With Enclosure 48 ~4* 41* l~ark Gold Without lS Enclosure 48 28* 8* Dark Brown *Values are an average of at least ten creel set-ups.
The feed yarns were supplied to both set-ups with an initial MOY of 35 % . Each of the runs 20 continued for about six hours and, at the end of six hours, the creel set-ups without the enclosure, had yarns with a MOY of only about 20%. On the other hand, the MOY for yarns in the humidified creel of this invention maintained their initial MOY of 35%
throllghout the runs.

The other feed yarns (identified as Yarn #A and C, above) were, also, heat treated in the oven of Example 1, above. The treatment temperature and the treatment tension were maintained the same as in :~xample l; but the heating time was modified in accordance with the different yarn deniers. Yarn #A was heated for about 3.6 seconds and Yarns #C was 30 heated for about 6.7 seconds. Yarn #B was, as treated from Example 1.

All of the heat treated yarns were tested for optical defects using a yarn defect inspecting device sold by Lindly and Co., Inc., Mineola, N.Y. under the trade designation Lindly Ultra II Yarn Inspector, Model 2070. To test for defects, the yarn to be tested is run through the 35 inspecting device with the ~im of detecting protrusions from the main thickness of the yarn.
The number of ~_` _ 3 13~9~

protru610ns ~ taken to be an lndication of the number of defects ~n the yarn under te~t. The defect level is reported a~ the number of defect6 per 5000 yards in6pected; ~nd the yarn which wa~ lnspected in each case of thi~ example, was the last of the yarn to be heat treated in the run. Defect levels ~or all of the Yarn~
with and without the enclosure of thi6 invention are reported in Table 3, below.

Y~rn Defect Level # ~#/S000 y~rds of yarn) A

With Enc}06ure 85^
lS Without Enclosure 650 With Enclosure 180 Wlthout @nclo6ure 1120 C

2~ ~lth Enclo6ure 190 ~lthout ~nclos~re 1400 ~These vnlues are an ~ver~ge o~ ~t l~t ~ co~plete to~te wh~r~ln 5000 yard~ o~ y~r~ wfl~e ln~p~t~d.

Claims (11)

1. Controlled humidity creel apparatus for maintaining a high yarn moisture content during storage and unwinding comprising:
package support means comprising a spindle for supporting a yarn package for unwinding;
enclosure means for providing at least a partial envelope about said package on said package support means and about at least a portion of the yarn adjacent said package being unwound, said enclosure means at least partially isolating the atmosphere within said envelope from ambient conditions outside of said envelope;
humidity controlling means comprising;
gas circulation means for circulating gas through said envelope provided by said enclosure means;
moisture supply means for supplying moisture to said circulating gas;
humidity measurement means for measuring the humidity of the gas being circulated through said enclosure means;
control means responsive to said humidity measurement means for actuating said moisture supply means when the humidity measured by said measurement means is below a predetermined level whereby the humidity level of the gas within said enclosure is maintained at or above said predetermined level.

2. The apparatus of claim 1 wherein said gas circulation means comprises a supply pipe for introducing gas into said enclosure means, a return pipe for receiving gas from said enclosure means, a main leg connecting said return and supply pipers, and a blower in said main leg for conducting gas received from said return pipe into said supply pipe.

3. The apparatus of claim 2 wherein said humidity measurement means measures the relative humidity of the gas in said return pipe.

4, The apparatus of claim 1 wherein said moisture supply means comprises an ultrasonic mist generator.

5. The apparatus of claim 1 wherein said predetermined humidity level is above about 90%
relative humidity.

6. The apparatus of Claim 5 wherein said predetermined humidity level is from about 90 to 99%
relative humidity.

7. The apparatus of claim 1 wherein said package support means comprises a plurality of spindles for supporting a plurality of yarn packages for unwinding, said spindles being arranged for unwinding of said packages with yarn being unwound to form a warp.

8. In a process for treating never-dried p-aramid yarns including unwinding a package of precursor yarn having a moisture content of greater than about 20% based on the dry weight of the yarn and supplying said yarn for subsequent processing, the improvement which comprises unwinding yarn from said package while exposing said package, the yarn being unwound, and at least a portion of the unwound yarn, to an atmosphere having a relative humidity of at least 90%.

9. The process of claim 8 wherein the p-aramid yarn is poly(p-phenylene terephthalamide) yarn.

10. A process for maintaining a controlled moisture content on never-dried yarn prior to further processing comprising:
mounting a package of never-dried yarn within at least a partial envelope;
maintaining the relative humidity of the atmosphere within said envelope at above about 90%; and unwinding never-dried yarn from the package and withdrawing said yarn from the envelope for further processing.

11. The process of claim 10 wherein the never-dried yarn is made from poly(p-phenylene terephthalamide).