CA2109463A1 - Technical superlight threads of high mechanical resistance, process and plant for their manufacturing - Google Patents

Abstract

ABSTRACT
The invention relates to a type of synthetic superlight threads of high mechanical resistance manufac-tured as tubular filament having their inner channel -the lumen - with very thin and resistant walls.
The invention relates also to a process and a plant for manufacturing these threads, through which it is achieved a strong molecular orientation in the polymeric structure of the film representing lumen's walls.
The super light threads of high mechanical re-sistance are advantageously used as reinforcing structures in composite materials, in energetics, medicine, chemistry.

Description

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'r~CH~ICJ~L SU~E~LI~,HT 'ri1~E~DS 0~` HIGH IilECi~.ANIaAL
A1~C~, P~OCE~S hN~ PLAl~ 'rHEI~lV~NUb'Aa'l'URINC,. ~:

'l'he pre~ent invention relates to ~uperli~ht tilreadc o~ h mechanical re~lstance, and al80 to a proce~s and a plant for their Inanufacturin~9 these thread~ being used as reinforoir~ tructure~ in compo~ite materials m~dant ~`or tra~port mean~, furniture, civil and industrial buil-din~s, or for special applications in medical techni~ue, energetic~, water purifi¢ation, climatiæation and equiptn~nt~
lo for chemical technolo~ie~
'l1hreads with lumen are known, created for tex~
tile uses which, i:n order to decrease the fabrio or knitting wei~ht and thus to decreac~e the amount of pol~ner used, as well a~ in order to improve some important qualitie~ for their wesr, lilce: handle, water absorption, weibht, thermal in~u~ ~. ~ ~
lation~ are spun with ~peoial threading dies, -to obtain threads hclvin~ inner channels ~ith different cro~s-section profile~
~ lerc are al~o known tubular glas~ yarns and processes for their ~anu~acturin~ by "pulling" the glass . ::~`.~.. ".
throu~h ~pecial threading die~. In comparison -~ith full glas~
yarns, these yarna.have a omaller weight and a higher ribidity. .
~ l~herf3 were al90 manu~f~ctured tubular monothread~
: ~or building ~ome ef~uipllflents h~vin~ selective p~vrmeable Inem~
branes~ f'or f~eparation~ based on rever3fa oamosis, ~or medical .
techni~ue~ ba3ed on dialy~ifs, for in~ufetrial ~a~ef3 ~vparation t echnolo~ie9 9 etc ~
~rocofsfaes lor their manufacturing are known, U~ pecial nozzlea5 the molten ~pina~le yol~rner~ or che solutiorl o~ polymer boin~ continuousl~ extruded through the 30 circular ~i~t of a threading di~, into an appropriate f~Olidi~
fication medium and, in order to create and ef3tablish the -.
circular ~hape oi the tubular monothroad in its cro3f~
aectioll, durin~ fspinning it i~ sontinuouf~3ly introduced a ~ -' 2 1 ~

fluid me~ium~ gas or liquid, undrr a gm~ll pr~sure 9 using a sE~cial deviee, like a ~yringe.
'L'he disadvalltclge of all the~e produets and proces~e~ Ior their manùfaoturing is that one eannot be obtained tubular thread~ having a very high meehanieal re-sistanee and, in the same time, a ~mall speei~ie weight~
meaning a minimur~ amou~b of polymer incorporated and~ as a e~ult, having their w311s with an adequato minimurn thickne~
lo The disadvantage of tubular thread~ thu~
produeed i~ that their resi~tanee i9 not very high. In all -the known ea~ of the prior art, the polym~r eomprised in the tubular tnread wall~, a~ter ~olidificatio~, aehieved .
after the spinning proees~ from the molten mass or the 80 lution, has no molccular orientation, or only a partial one, the ultimate tensile strenght and elongation having r~mall value~, uneati~faetory ~or ~peoial teohnieal u~e~
The aim of the pre~ent inventinn i~ to provid~ monofilamental thread~ havin~ speci~ie eb~ential 20 physieo-meehanie~l eharaeteristies rslated to their weig~ht, -much higher than those o~ Jimilar known produets and, at t.he aame time~ incorporatin~ Ininimum pol~ner amount~ in comparir~orl with these; another aim is to provide a speci~
lic proee~s for their manufacturing.
L'he technical thread~ with lumen, of high mechanieal re~i3tanee and light weight~ aeeording -to the present invention, withdraw the above mentioned di~advan- ~.
tage~ and, 0}1 purpo~e oi increa~ing their mechanicc~l re~
~i~tanee and at the aarne time decrea~ing the illcorporated ~o poly~er quarItity~ have ~he lumen walls thin and con~titu- .
ted o~ a high orientated polymeric ~ilm, by it~ stretching o~l two perpendiculc~r direction~ ~ axial a~ld tangential to the c~lindri¢ wal1s.

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~ e proev~lE lo.r their In~nufacturing consi~t~
in tne lollowin~ e~æential step~:
- t~le ~hapin~ ol the technicQ1 thread with lumell in a cru~e ~tate, by extrucling a ~yrl thetic or fl na- :
tural polyrner from it~ alelt or æolution t~lrou~h a no.~zle ` ::~
of a special de0i~n, u~ing proce0~eæ known per ~e;
the ~tretchl~g of` the wall o~ the tec~mi- :
oal thread with lumen in a tangential direction to the cylindrical body of i t by continuou~ in~roduotion of a ~ .
lo ~luid under pressure; this operation i8 carried out con~
co~nit~nt or succesively, or succesively at the Yame time . . . `.
with the axial ætretchin~ and the ~pinned product spoo~
ling operation3;
- the ætretcslirlg in axial direction o~ the -~
lumen thin ~all, by "pulling" the thread usin~ mechanicv ~y~temæ, known per Ye, consi~tinO of drivin~.~ cylindrical : :~
roller~ - "Ylidin~ block~" - and ~'pressure" roller~ which -.
~acili~ate t~lead adherence to the moving bod~ o~ the `~
driving roller, while the thread i9 bein~ moved continu.
~o ou01y in-between the roller~ groups, wnich are rotatin~
at different speeds~ the elongation bein~ controD~d by thc ~uitable ad~ustment o~ their ~poe~ o~ turning~
'l`he temperature at which the ætretching o~
perations are accomplished is deterl~ined by the nature o~ the polymer used; u~ually it i9 over itB tranæiti~n :~
tenlperature of order II ~with lo - 150C, uYu~lly by lo 30a ) . '''~
The ~tr~tching ratio~, both a~ial and tan~
gential, are determined by the polymer ætructure an~ the wetting perimeter lenght of the nozzle u~od for the ex~
truoion of tho thread with lumen; the axial ratio~ are usually in the range of 1..~20, ~referably 1...5, and the tangential ratios in the ran~o of 1...10, pref`erably lo o4~

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'l`he pIant~ implementing the process of continuou~ marlufa~turing of' technical, superlight threads of hi~l mecha~lical re~i~tance and sm~ pe¢i~'io weight ¢on~ists o~` two part~
I. the part of producing the techni¢al tnr0ad with lu~en in crude state~ consi~ting o~: equipment for f'oeding the polymeric product 9 having a gear wheel pWIlp for viYcou~ ~lixtur0a, a nozzle of sp~cial deoigrl with a system for ~haping tho oircular profile of the thread lo with lume~; an equipm~nt for ~olidification of the epur2 ~'ilament, consi~tin~ mainly of a bath with a cooling medium in the ¢ase of me~t, or a suitable coagulatioll medium for ~:~
polymer~ in ~olution; dosage device for the fluid employed ~or ahapin~ the circular cross_section; an equipmen-t f'or advance-l extraction o~ the polymer solvent or o~ the unre-acted monomero; stretching devices ha-ring oylindrical ro~
ller~ turning st difl'erent ~peeds; coiling and winding de- ;
vice. for the crude spun thread;
II, the part of stretching the tec~mical ~o tihraad with lumen, in it~ crude state, until reaching the e~tabli~hed mechanical re~istance and an ad~anced thinnes~ ~
o~' lumen's wall~, consistin~ of: ag~regates for ~,.ial 3tret- :-cllin~ and an aggre~te f'or ra~ial ~tretching compoeed, in ~ :
principle, o~ a continuous do~age ~ystem of a fluid under pre~sure into the tec.tmi¢al thread with lwllell, having a ~pe~
cial and ti~lt cormection; ~roup~ o~ driving cylindrical ro llers rot~ting under~ control at different speeds, that ma-nage the stretching; thread prer~ing rollers; coiling and ~ ~
I winding r3ystem f'or the technical thread with lumen; h~vin~ ~ ' ¦ 30 thin w~116 and bi~tretched.
l~'or manuf~cturing the tec~mical thrf~Ad~ with lurrlen, of high rrlech~nical r~sistance and thin wallr3, may be . u~ed all the ~pinable polyrners which, usually, ar~ employed - 4 ~

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in the technolo~y of ~ynthetic thread3 and fibres manufacture.
A8 unlimitative example~ ~or the pre~ent ~ ~
invention are the following synthetic and natural polymer~: -Ao heterochaill polymers:
- ~liph~tic polyamides (the polyamide 6, the polyalllide 6-6, the polyamido 6-lo, the polyamide 6-12,etc); - ~ :~
- arolllatic polyamide~
- polyurethane~
- polyoster~
lo - polyanhydride~, etc;
B~ carboch~in polymer~s - polyole~ines (polyethyl~ne, polyprop~lene~etc);
- polyacrylonitrile;
- halogen-vinyl polymers (polyvinyl chloride); :::~-- polytetrafluor etllylenc;
- chloro-fluoro-vinyl polymers, etc.;
aO l~atural polymexs (cellulo~e~, et¢D).
Th~ polymer~ u~ed for the thread~ of the pre~ent invention usually have ~trai~lt chain filiform ~ . . .
macromolecule~, their molecular mas~ varyi~g in wide range~
with value~ determined by the ~pinabl~ity character of the polymer, molten or in solution, value~ between 4,ooo and 70,0009 oorre~ponding to a degree of polymerioation of 30 ~
1~500; ~or heterochain spinable polymor~, the molecular : ~-:
weight i~ ~ituat~d in the range of 6,ooo - 30,ooo, pre~e~
rably ~,ooo - 20,000 alld the degree o~ polym0rization in t~le r~nge of 70 - l,loo; for carbo¢hain spinabl~ polymer~
the mole¢ular weight i~ situated in the rang~ o~ 25~ooo 50,ooo, preferably 30,ooo - 45,ooo and the dogree of poly~
merization in th~ range of 300 - l,loo, pref~rably 400 ., ~ ~ . ...
l,ooo.
'~he invention will be more detailed d~s-cribed in the following 5 example~ (which ar~ provided by :

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wa~ of illustration and are not intended to be limitin~
o~` the invention) in conneotion with the drawings 1, 2, 3 and 4 which re~re~ent~
- fit3ure 1 - technologioal diagram for the lnfl-nuf'ac~uring oi monothread with luTnen~ in its crude ~tate; .... :.. `
- fi~ure ~ - cros~ section of' a zone of' the ~pecial threadirll, die for 3pinnirl~ the monothread with lumen in crude state;
- ~igure 3 - techno:Logical dia~ram for the Tlla ~ ~ .
lo nuf':-~cturin~ oi' the thread wi~h lumen~ naving it~ wal:L~
bi~tretched;
- figllre 4 - cros~ se.cti~)n oi' the injectio.n ~:
device i'o.r the i'luid under pre~ure~ involved in the ra~
dial ~tretohin~
~ le 1. In a tank 1, l'itted with a heatlng jacket, the s~im~ble polymer in molten ~tate is fed, where- ~ .
'rom it flows through a pipe 2 to a gear wheel pump 3 and ~'rolll there through a connection pipe 4 into a ~pecial no- .
zzle 5 9 that continuou~l~ di6chargas the thread; thi~
thre~d enter~ a ~olidif'ication bath 6 and is directed and maintained immersed by the guide roller~ 7 and 8.
ln a bu~f'er tank lo Q ,a~ unaer pro~sure is . :~
continuously intro~uced through a ~eed pipc 9, then the gaa flowo throu~h a connectin~ pipe 11 9 a control valve lZ, pipes 13 and 15 and a flow-meter 14 and i~ inaected in the center of' the threading ~ie 5 for the continuou~
axtru~ion ot' the thread with lumen, in order to ~hape it~
circular cro~3 ~ection.
'rhr~ad~ with lu~nen in crude ~tate, after ~o- .
lidif'ication in the bath 6, are paeeed over a roller 16 and introduced in a stretchin~ machine 17, having ten~ion rollar~ 18 that turn round at ~uitable ~peed~
~ 6 - ;

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;~hread3 thu~ produced are pas~ed through a ~ ''~;`' heating ~ystern 19l then through a t~tretching machine 21 having cylindrichl rollers 20 that turn round ~t different 4p eeds, and finally the~r are ~pooled on a spooler 2~o Ln the ~econd l~art o~' the plant, ~or the bi -~
Ytretchin~ prooos~, the continuous thread i~ talcen over by a spool 2~, then b~y the c~lindrical stretching roller~
24 a~3~mbled on the stretching machille 25 and pa~seEt through a heating ~ystem 26; after that is taken over by the cylin lo drical tensioning roll0rs 27 of a ~tretching machine 28, then by the roller~ 29, ~o and 31 ~hat change its direc~
tion and ~end it into an ag~re~ate 32 for radial strstohing and fin~l spooling.
'llechnical grade nitrogen under pre~sure is ~upplied into the plant through a f'eed pipo 33 and ~tored ~' in a buffer tank 34. It flow~ through a pipe 35, a control valve 36, a measuring diaphragm 379 a pipe 38, a connecting sleeve 39 and entero in a fixed supplying "head" 40 and then iIl a tight connecting device 41 a~embled on the rotating ~o part of the aggregate 32 ~le tight connecting device 41 con~i~ts mainly of the injection head 42 and -the tightcning part 43 of the thread with lumen end 44. ~ ~;
Periodically, t~le "fille~ upl' apool~ on the aggregate 32 are repla¢ed by empty ~pool~
Irl the tank 1 of' the ~bove de~oribed plant ther~ are introduced 500 kg molten polycaproamide having the average molecular m~sY 14,ooo anci an average degree of poly~erization of 125.
'l~he melt of polycapro~mide, havin~ the tempe-r~ture of 250 - ~55~ i~ taken over by the gear whe~l pump 3 and inject~d through a ~ecial deaigned thr~ading die 5 with a llow rate oI lo.o3~ kg/hour-.
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'l`he pullin~ ~peed Ior the crude thread with lumen and al~o its ~peed of enter~ing the solidification bath 6, usin~ ~ater Yor cooling, i~ of' 60 m/min.
S~multarleously, from the buff'er tank lol through the corlllecting pipe 11 9 -the control valve 12, the ~'low-rneter 14 ~nd the connecting pipes 13 and 1~, technical Orade nitrogen oX le~s than 5 ppm oxygen content i~ fed into the speci~l de~i~nedthr~r~i~n~die 5, continuously, with ~ flow rate of 11 1/rnin.
lo ~n th~se condition~, t.he Yilarnent denier of the spun thread with ~umen in crude ~tate i8 25,139 dte~, corresponding to itr~ external dia~ter of 3.o ~m, itB inner di~meter of 2.4 Imn and the wall thickner~s of about oO3 mrn. .
'l~he rotative spee~ of rollers in .step I of .
otretchin~ is of 14 rpml in ~t~p II of ~tretching of 43 rpm and in r~tep lII ol 70 rpmO
!~le temperature in step I ol' stretching is 150~ ~nd i~l stepr~ ~I and III iB about looC. In the~e ~:.
condi~ions~ the axial r~tretching ratio is 1 : 3.2~ :
~o ~imultaneously, lrom the buffer tank 34 for t ecnnical ~r~dc nitr~en the ga~.ipa~,e~ through th~ pip~ 35, ::
the coJItrol valve 36, ~ e rneasuring uiaphragm 37 and the pipe 38, an~ through a sleeve 39 enterr~ the fixed ~upplyin~ head 40 ol t~le rotatirl~ device ~ for radial stretchin~, in ~uch :~
an amou~t that the radial ~tretching ratio is 1.6. 'l'hi~
ratio correr~pond3 to a~l increa~e of the circular cro~ ~ec~
tion perimoter lengLlt of the bi~tretched tllread ~vi-th lurnenO
rhe thread with 1umen rne.lluf~,ctured in the above de~cribed WaJ haa bistretched wallr~ with a fil~ment denj.er in ~tr~tched ~tate of 79~o ~tex, A $~trenght ol 16,60c) d~
an elong~tiurl of 1592 ;~0 and a telldcit~ ol ~.1 da;J~dtex.
~ he thread v~ith 1umen h~ an externa1 di~meter of 1.9 r~n a~ld rl wall -thicknee~ ol 200 micron~
.

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~ xam~le i~o U~ing the plant de~cribed in example 1 and shown in the drawhl~ 1, 2l 3 and 4, molten polycapro alllido having -the ~allle charucteristics a3 the polymer used in exalllple 1 i~ fed ill the tank 1.
~ rhe flow r~t~ of the spun polymer i~ 4.5 h6~h and t~lei pullin~ out ~peed ~rom the th.reading die of` 140 In/mi l'he flow rate of the nitrogen ~uppliod into the apinning device 5 i~ of ~.5 l/min.
In the~e conclitions it i~ obtained a crud~ thread lo with lumen havin~, a filament denier oi 5586 dtex, an exter~
nQl diaMeter of 1.1 mm and a wall thickne~s of loo r~icrons.
The rotative speed of rollers during r~tretching is `~
14 rpm in ~tep I, about 4~ rpm in ~tep II and about 70 rpm in etep III, and the temper~ture u~ed i~ o~ 160a in ~tep I . :
an~ 120a in ~tep 1l. In the~e condition~, the axial stret-ching ratio obtained i8 of 1 : Z.79~
In the rotating device 32 i9 f`ed such an amo~lt of nitrogen, that the radial stretching ratio i~ about 106. `~
According the proce~ deacribed in thio example, ~o a thread with lwnen having bi~tretched wall~, the filament denier in stretched ~tato 1799 dtex, ~ ~tren~ht of 4,500 dal~, an elongation of 21~36 /0 i~ manufactured. Ite e~ternal diameter i~ of o.8 mm and it~ wall thickne~s about 90 micxon~
l'he tenacity o~ the tec~ical thread ~hu~ obtained i~ of ~ :
50 da~/dt~
Exam~le 30 B~ u~ing the ~ame plant a~ in example~
1 and 2, 45o kg polyethyleneterephtalat in molten ~tate, having an average ~olecular mas~3 of about 22,ooo and an average degree of polymerization of 176 ~re employed~, '~he tempera~ure of the poh~ethyloneterephtalAt melt i~ ma:~tainad around 295Co ;~
In the special ~pimling device are continuously ` - ~:
fed 5.92 k~/h polymer anil the pulling out speed i~ of loo r~ in. In the ~me ~pinning devi¢e are also fed 5 l/min _ 9 -~

":, ",, ., " , -, ~,, , ~ , . i, ~

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teolmical grade nitro~en. It i6 obtained a polye~teric thr~ad witn lW1len~ .in cr~lde ~tate~ havirlg a ~'ilament dcrlier `.
o~ 10,869 ~tex, ~n e.cter.nal di~meter o~ 202 mm and a wall tnic~neos of ~L~out 200 mioron~0 This threud i~ ~ubjected to bistretchirlg o~eration~ aa de~oribed abovc, usin~ the fo-llowing stretcl~ r~ltio~:
- axial ~tretclling 1: 401 - radi~l stretching 1 0 108 -~
'l`he stretching temperatures are of 1~5C in lo ~tep I and 145C in ~-tep Il~
lt is obtaincd a bi~tretched polye~teric thread ving an exterrlal diameter of 104 n~l and a wall thiokne3 of ~bout 140 micron~0 The thread ten~lc.ity is about 1~9 da:N~clte.
Exalllple 40 In the plant described irl the previ-ou~ exàmple~ are fed '~oo kgr isotact:ic polypropylene, in nolten st~be, hdvin~r an average molecular weight of 145,ooo ~ ~:
~nd ~ melting point of 164 - 166Co The pol~propylene melt is maintain~d in the bu-ffer tank 1 at a temperature of 285aO
In the special spinning device are continuou~ly ~ed 12 k~/h polypropylerle melt and 180 l/h teohnical gr~de nitro~enc It is obtained a crude state polyprop~lenic thread .. :
with lwnen, having a filament denier of 12,107 dtex, an ex- .
ternal diameter o~ lo9 n~n and a wall thickness of 400 mioron~0 Irhe axial 3tretchin~ ratio i~ 1 : 805 and the :~
radial stretchin~ ratio 1 : 2.4. The temper~ture u~od in .
stretching operation~ i9 in the r~nge 130 - 150C~
It is obtained a monofilame~tal polypropylenic thread with its walls bi~tret¢hed, having th0 thread oxter~
nal diameter o~ mm and the wall thicknes~ of about 90 micron~O The tenacity of the polypropylenic thread with lu- :
men i~ 2.1 dal~/dtex and the elongation of about 18 ~0 ~ xample 50 In a plant ~irnilar to that used in the previou~ exarnple~, with the only differenco that the ~o~

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liai~'ic~tion b~th 6 is fitted with a~c~$orie~ for inlet :'~
and outlet of' ~pi.nnillg solutionc a~d for advanced extrao~
tion of` the ~olvent ~'rom the epun thread, are introducsd ~' ' :
~oo kg pol~acrylonitrile solution in etllylene carbont~te, .,:, with the followin~ composition~
- 15 ~ polyacrylonitrile - 74 ~o ethylene carbo.nate : :
- 11 ,~ w~ter.
I~he ~olution i~ kept in the buffer ta~k 1 at I -~
lo a temperature of 9oC0 ' .;:~;
The average molecular weight of polyacryloni-trile in thi~ solution i~ o~' 38,ooo~
The ~pinning devioe 5 i8 oonti.nu,ou~l~ fed with `:;. ~',''.
30 kg/h polyacrylonitrile ~olution and 16 Icg/h of 18 % ethy~
lene carbon~te aqueou~ ~olution.
I~'he coagulation me~ium i~l the solidii`ication bath 6 i3 18 - 20i'h ethylene carbonate aqueou~ ~olutionO
The pulling ~pced at the threading die 5 i~
OI` ~ m/min. . '~
~o ~f'ter washing and drying in a co~vention~
plant, kno~n per ~e, not repre6entcd in thei drawing~ o~
the pre~ent invention, a crude pol,yacrylonitrilic thread with lumen i~ obtained, havillg a ~'ilam~.nt dcnie.r of about 6,~oo dtex, un eY~te.rnal di~met~r of 1.7 mm and'a wall thick~
Iles~ OI l~o mi¢rons~
he crude polya¢rylonitrilic thread wi th lume t~lus obtainea i~ aubjccted to axial an~ radial ~tr~tching ac¢or~ing to the proce~s uoed i.n example~ 1-4.
l'he temperature employed in the stretchin~ ope~
~o ration~ i~ about 140C. The axial stre-tchin~ ratio uoed i~
1: lo an~l the rad.i~l ~tretching ratio u~ed ii3 1: 2.
ln these condition~, a bistretched pol;yacrylo~
nitrilic thre~ obtained, h~ving the follo~ing chcir~c~
ristic~

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; ,lffr~

2 i ~ ~ 4 ~

- extern~l diallleter o.~ mm - wall thickne~s 70.o micro - ten~cit~ 1.3 daN/dteY .
The technical ~upe~ t threads ol hl~h mechan.ical reai3-tance, manlll`actured ac--ordin~ to the proaeIlt invelltion~ h~ve the advanta~e o~ a high mechanical re~istan- :
ce relate~ to a minim~l wei~ht o~ them, 'l'ne value of this relative resistande make it ::~
pos~ible to use them auccessiully in the manufaoturing of lo superli~ht material~ of ~igh mechanioal re6i~tancep In table l,comparative data of usual,known materials and materials based on the threads according to the invention are preaentedO
'rhe data pre~ented in table 1 demon~trate that the ooulpoaite material manufactured with superlight threads of hi~h mechanical resistance (position~ 9 and lo) -~
na~ a densi~y muoh maller than materials known up to date and simultaneou~ly ha~ very high mechanical resi3tanee, the ~ ;
ratio mechanical re~i~t~nce/den~ity being the biggest in ;~
compariaon with all material~ kno~n in the art.
Based on this property, their use, e~pecia~
lly advanta~eou~ in tran~porlt means industry - especially in aviatic industry ~ lurniture indu~try, in civil and indu~trial building3, in ~nergetios, water purification, ;~
climati~ation and diffcrerlt chemical t~chnologi~
highly recomme~ded.
New. mat~rials.ba~d on the u~o of auperlight threada of hi~l mechanical re~istance make the investment :~
co~t~ minimal due to the maximal diminishing of amount~ of energy-¢on~umer materiala.
b~urthermore, the lar~e ~cale us~ of the~
materials in transport indu~try will contribute to th~ ~ub~
stantial dirninishing of the en~rgy ¢on~umed by them and to the reduction, ~mong others9 of the f~uel con~umption. :~

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rabl o ~en~it~y 'ren~ile ~ensile 9 tre.nght ~:
o~ Materlal strc~ght4 per density crt, lo 2 ratio~lo4 ' (dah~m3) (~aN/m ~(m) :
'ld Steel7860 3400 0,4325 J ~ `
2 0 Alloy stcel7860 7200 Ot9160 3. Aluminiwn 27001100 0,4074 4. Alumini~ Illlo~r~ 3200 2000 0,6258 lo 5. Wonrein~or¢od pl~stics 133~ 20~ 79 6~, ~tratifiod reinforced plastics17ùC) 1700 1,0000 :~
7. ~i~ferenti~lly rein~'orced plaotics lS~)() 10800,6'75~
8. Wood cii~ferel1t species 7C)U 7U0,li~'~)0 fir tree 370 58 ~,1560 9. ~omposite m~terial based on sup~rli~lt thread~ of lligh mechanical re~istarloe ~ 2 rr~n acoordin~ to the illvelltion 190 1596 8,0~00 lo. ~orrlpo~ite material based on superli~At threuds o~ high mech~nic~l resi~tance ~ o.~rn/n ~ccordin~ ~o the invention 281 2198 'I,80(JO

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Claims (8)

1. Technical threads with lumen of high mechanical resistance and light weight, characterized in that they have lumen's walls thin and made of a highly orientated polymeric film by its stretching on two perpendicular directions -axial and tangential to the cylindrical wall of the thread.

2. Process for manufacturing technical threads with lumen of high mechanical resistance and light weight accor-ding to claim 1 characterized in that it consists of three esential operations:
- shaping of the technical thread with lumen, in crude state, by extruding a synthetic or natural polymer from its melt or solution, through a special designed nozzle, using processes known per se;
- stretching of the wall of the technical thread with lumen in a tangential direction ?? to its cylindrical body, by continuous feeding of a fluid under pressure, this operation being carried out concomitant or successively, or successively at the same time with axial stretching and spi-nned product spooling operations;
- stretching in axial direction of the lumen thin wall, by "pulling" the thread using mechanical systems, known per se, consisting of driving cylindrical rollers and pressure rollers which facilitate thread adherence to the moving body of the driving roller, while the thread is being moved continuously in-between the rollers group which are rotating at different speeds, the elongation being controlled by the suitable adjustment of their speed of turning.

3. Process for manufacturing technical threads with lumen of high mechanical resistance and light weight, accor-ding to claim 2, characterized in that stretching operations take place at temperatures higher than the transition tem-perature of order II of the polymer used, by about 1o-15o°C, preferably by 1o - 3o°C.

4. Process for manufacturing technical treads with lumen of high mechanical resistance and light weight, according to claim 2 and 3, characterized in the the axial stretching ratio is in the range 1....2o, preferably 1...1o, and radial stretching ratio is in the range 1...1o, prefe-rably 1...4.

5. Process for continuous manufacturing of tech-nical threads with lumen of high mechanical resistance and light weight, according to claim 2...4, characterized in that as polymers for the manufacture of technical threads with lumen of high mechanical resistance and thin walls are used all the spinable polymers which, usually, are employed in technologies of synthetic threads and fibers manufacturing, preferably :aliphatic polyamides, like polyamide 6, polyamide

6-6, polyamide 6-1o, polyamide 11, polyamide 6-12,etc, aroma-tic polyamides, polyurethanes, polypropylene, etc., poly-polyolefines, like polyethylene, polypropylene, etc., poly-acrylonitrile, halogen-vinyl polymers, natural polymers,etc.
6. Process for continuous manufacturing of tech-nical threads with lumen of high mechanical resistance and light specific weight, according to claims 2...5, characte-rized in that the polymers used have average molecular weights situated in the range 4,ooo...7o,ooo corresponding ?to average polymerization degrees in the range 3o...1,5oo, for the different types of polymers used these characteris-tics having the following values;
- for heterochain polymers the average molecular weight is situated in the range 6,ooo - 3o,ooo, preferably 8,ooo - 2o,ooo and the degree of polymerizat ion in the range 7o - 1,1oo, preferably 9o - 1,ooo;
- for carbochain polymers the average molecular weight is situated in the range 25,ooo - 5o,ooo, preferably 3o,ooo - 45,ooo and the polymerization degree in the range 3oo - 1,1oo, preferably 4oo - 1,ooo.

7. Plant for implementing the process of continuous manufacturing of technical superlight threads of high mechani-cal resistance and light specific weight, according to claims 2...6, characterized in that it consists in two parts:
I. the part of producing the technical thread with lumen, in its crude state, consisting of: equipment for fee-ding the polymeric product, having a gear wheel pump for vis-cous mixtures, a nozzle of special design with a system for shaping the circular profile for the thread with lumen, an e-quipment for solidification of the spun filament, consisting mainly of the bath with a cooling medium in the case of melt, or a suitable coagulation medium for polymers in solution, a dosage device fro the fluid employed for shaping the cir-cular cross section, an equipment for advanced extraction of the polymer solvent or of the unreacted monomers, stretching devices having cylindrical rollers rotating at different speeds, coiling and winding device for the crude spun thread;
II. the part of stretching of the technical thread with lumen, in its crude state, until reaching the established mechanical resistance and an advanced thinness of lumen's walls, consisting of aggregates of axial stretching and an aggregate for radial stretching compound, in principle, of a continuous dosage system of a fluid under pressure into the technical thread with lumen, fitted with a special and tight connection, group of driving cylindrical rollers ro-tating under control at different speeds, thus managing the stretching, thread pressing rollers, coiling and winding sys-tem for the technical thread with lumen having thin bistre-tched walls.

8. Plant, according to claim 7, characterized in that it consists in a tank (1) fitted with a heating system for the molten polymer or the solution of polymer, a connec-ting pipe (2), a gear wheel pump (3) for viscous mixtures, a connecting pipe (4), a special designed nozzle (5) having a system for shaping the circular profile of the thread with lumen, an equipment (6) for the solidification of the spun thread, a roller (7) that ensures the immersion, a roller (8) for direction, a pipe (9) for feeding the fluid that makes the circular cross section shape of the thread, a tank (lo), a control valve (12), a flow-meter (14), a connecting pipe (15), a directing roller (16), an aggregate for axial stretching (17) with driving cylindrical rollers (18), a heating device (19), driving and stretching rollers (2o) fitted on an aggregate for stretching (21), a spooler (22), a despooler (23), stretching rollers (24) assembled on an aggregate for stretching (25), heating device (26), cylindrical rollers (27) assembled on a stretching aggre-gate (28), directioning rollers (29), (30) and (31), an aggregate for radial stretching (32), a connecting pipe (33), for feeding pure nitrogen under pressure, a tank (34) for technical grade nitrogen under pressure, a connec-ting pipe (35), a control valve (36), a measuring diaphragm (37), a connecting pipe (38), a connecting sleeve (39), a fixed feeding head (40), a tight connecting device (41) consisting in principle in the injection head (42) and the tightening device (43).