Process for the production of sharp-edge fibers

Oct. 31, 1967

A. L. BREEN

PROCESS FOR THE PRODUCTION Original Filed May 27, 1953 of sharp3,350,488 edge fibers

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Oct. 31, 1967

A, L. BREEN 3 35η jnn or_1Si«l _Fii._d X™' ^raOOUCT™ ”

Sheets-Sheet 2

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United States Patent Office 3,350,4 ‘————--------Patented Oct. 31, If

PROCESS FOR THE’PRODUCTION OF Ai,_r; T ^HARP-EDGE FIBERS ®el., assignor to E. I.

a corporation of Delaware ^mpany’ ^W1I“ington, Del., Original applications Mav 27 io« c and June 7, 1962, Ser ^o ’ 200¾^ ‘ 738,166,

3,188,689, dated June 15 ΐο«°’η·⁸’·?Τ ^Pafent No. plication Mar. 3, 1965, Ser. No? 436*888 ^ap'

Claims. (Ci. 264—171)

20™ν ffled Juftft¹ Sftft ft ^{aPpHcati0n Ser}· No. 3,188,689 on June 15 ftftft^{as U}'^S· cation Ser. No. 738,166, fifed M’ay 27°^°^ of a ftXoXSft ‘° ^the “-ufacture of filaments of SrfesiS S ‘ft ^Preparati0n edges in cross-section by eXfeTof ft?™^{8 sharp}tions of fiber-forming polymers Thk · ft “^β1 °^{Γ Solu}‘ al ™ϊ ° filaments _oftudinal edges. having one or more sharp longiΪ °” ·>“ m the course of the following discussion ^{β aPParent} a composed of segments of at 1 ft muform cross-section polymeric comp“oSns saft ft ^lW° ^dlssimil“' synthetic two segmentsa TJast ft_e TJTft^{n having at least}tact between such seXnTrf theft ™^{y COn}substantially point contact is fxtrudeTftft ^ymeft^beingcomplished through the use of th · may be acmore completely described below AftTtoftX™^ sired, the filament may be separated ft ft^awing’ ^{as de}' &SS.SZ5 «_s»»°wp Sts _h„_ei o„X^rS,The segshape as shown in 110 of FIGTTRR ο· n t,^{ln a tear}’^dropa.» a lens-shape asshow™“K ^SE^P“”^,! — as in the shape shown in 107 of FIGURE 7· 3 =h ^{5 Γ Sacb}as in a plane or curvilinear tnftX· ⁷’ ³ ft^{rp p01nts}sharp points such as in a fi ^agf^e’ ^{or a} multiplicity of ^0,te έ — for this pu_W “ SeTE*?; 5“’

Plate and plateaous 5 of thft °^PP0S?^{ng face of the}Plate. The back Xe - ^f ft ^protrusions from the fn 19 and inner ftall 2finft^Pft¹ft^ned?^{)n tOp by outer} * I chamber 9. The annular nh ft ^{&T cbamber} 8 and cent) constricted regions betweenfthftt ^com“^unicates with t holes 31 and orifices 32 an dftft ° ^{PlateS throu}S^h le; municates with the inte’rven· ^be ftⁿ.^traI chamber coi region through holes 11 Theftwoftlate^{ly UnCOnstricti}Place by can 18 whirl· -oft two plates are retained back Plateftnd is feed to thftf^adft ft^{t0 the end of} « 17. The upper part of thehnZ- Z^ ^{with set screv}suitable pftft orfttfte r ± ft⁸<ⁿft^shown> receivt nection to the two ch am he ^{PP y}, “^eans f°^r separate coi bution or filtering spaces XS pTlOhrS ^rOFSu^aRftft^iOh^ning °^{f the tW0 Ρ1}^°· ^{Plat6S 6η8}^Γ6front pFaS Ap5a^OringVthft^Ced ft ^{the plan} °^{f tb}‘ concentric wX“^ eac!

about a circle inside the outer saskeft ft ft ^{Y SpaCec}view and in FIGURE 1 each orifir ^A· ^{hown ln tbis}21 at the exit end aft iftft ^&amp; ?^{nslsts of ca}PiUary to the capillary from the plate;iu Alsn vic'Ki ending m a shallow annular groove isftaskrn 6 m ®’ ^supportedof the back plate beingSariv Jr ft ftft °^PP°^{slng face}seal between the two plates FIGURE^ h ^{a S}°°^dformly on a circle betweft tft ft ^apertures spaced uniings located ftftftft'ft. ft ^Wft^S’ ^{and four ope}“ inner wall. As shown in this vie_W^C thftaft ^byor back plate opposite the S of thf hftT “ft* ‘°^Ρeach composed of four terminal ft⁶ .^bottom Pl^ate are ⁰ HGUR^Opftft^{bOre 0Γ kad} holeftl ³² “^ίΓ°cross-sectional views^f represent at'° ^{represent transv}erse of the present invention , ^{p esentatlve} composite filaments ofSrpliM*™™;™,_s-_{!MionaI vi}„ _{of om}from the composite filaftent ^{filaments after} separation pr«efa of through the opeffinft ft_tn ft ^Pft^;- ^{the former fl}°ws space between back and front^aS ίΪΧΧ° the latter passes’first through tft ^{extrusion orifi}ces while Plate and direcfly^ηΛ“ Vjf “ ^{Λβ back} “Sb?” -'“^{d in} ·“ cn bo ta.^P“T.™r,“’“,^f°' “ “ .““TJX? xsit ··

6» components should _h„_e i“X*£ · No.

issued as U.S. Patent appli15

3,350,488 ₄ angular segments of the filament and Ρ^^Τ® terephthalate) of „_r 33 containing 0.3% of T O₂ wa^ fed to annulus 8 and then through orifices 32 to form the formee cross segment of the filament s cros The two molten polymers were extrud of 9 5/10 0 by volume respectively at 290 C. an Cits¹ ““ SSχ·. c.

3Ϊ =3 7» i—

Icid in a Soxhlet extractor, removed rinsed with wrier and dried Despite the loss of about 50% of the fiber weight by dissolution of the polyamide sections the visua covering nower of the tubing was greatly increased, ih eriS Xg had a soft silk-like handle. and was scroopy The cross-section of filaments remaining 1 extracted fabric resembled a formee cross as shown

108 of FIGURE 7.

Example ll

Using the same spinneret as in ene terephthalate) of 26.9 containing 0.3% of TiU₂was fed/o chamber 8 of the spinneret and extruded as the segments of a composite filament designated 101 in FIGURE 4 while poly(hexamethylene adipamide) of 36 was fed to chamber 9 and extruded as segments of a composite filament designated 102 m FIGURE . The polymers were extruded at 290 C. and * 7 wound up at 400 y.p.m. The yarn was drawn 4.3 ><. over ' a 98° C pin. The resulting yarn had a tenacity °ⁱ⁴· grams per denier, and initial modulus of 56 and had a denier per filament of 8.3. A portion of the drawn yard was wound on a perforated metal bobbin and immersed in cold 98% formic acid for 3 hours. After rinsing an ⁴⁰ drying the residual polyester yarn had a tenacity of 3.8 g p d a Mi of 73, an ultimate elongation of 28% and total’denier of 80 for the 68 filaments then P^res“^b A typical cross-section of a filament is shown m 109 of

FIGURE 8. . . ,7-,7

A portion of the original yarn was woven into a 2 x Z twill fabric having 120 yarns per inch inthe wau> and 84 yarns per inch in the filling. The resulting fabric was immersed in 98% formic acid for 60 minutes until the poly(hexamethylene adipamide) sectors were disso from the composite filaments. The fabric possessed all 0 the properties of a silk fabric as liveliness and drape the subtle scroop of silk, the handle, the low denier per filament, the high modulus and good recovery P^roP^crt’₂A repetition of the above spin with positions of the Z polymere changed gives filaments which ^{after treat}-“ with, formic acid leaves fillet-shaped sectors of the poly ester similar to segment 102 of FIGURE 4.

Example III ' The following example illustrates the different crosssections obtained by varying the volume of pdjm delivered to various sectors of the composite laments Using tbe spinneret of Example I with a three mil shim, polyethylene terephthalate) of 7i_r 28.1 containing 2.0% of TiO₂ was fed to chamber 8 of the spinneret and poly (ethylene terephthalate) of v_r 31 fed to chamber 9. T polymers were extruded at 290° C. and the yarn wound up at 1000 y.p.m. The volume of the two polymers en tering the composite filaments were varied by adjustment of their respective constant displacement pumps. In the first spin the volumes of the pigmented polymer to the non-pigment polymer was 1:1 and Agents were obtained having cross-sections similar to that shown in FIG URE 4. When the ratio of pigmented to bright polymer

Lisly this is not necessary where one component of the r is to be removed by dissolution or chemical decorn ition Because of their commercial availability, ease processing and excellent properties ^the ^nde^ahon , vmers and copolymers, e.g., polyamides, po y . Tides and polyesters and particularly those that can readily melt spun are preferred for application in s method. Suitable polymers can be found.for instance long the fiber-forming polyamides and the P^oIy®^s‘® ·.„ are described in such patents as U.S. Patents ; 171 250 2,071,253, 2,130,523, 2,130,948, 2,190,770 and 465’319’ The preferred group of polyamides comprises Jy (hexamethytene - adipamide), bacamide), poly(epsilon-caproamide) and the. co ilvmers thereof. Suitable polyesters, besides poly (ethyl ie terephthalate), are the corresponding copolymers mtaining sebacic acid, adipic acid, isophthalic acid as ell as the polyesters containing recurring units derived •om glycols with more than two carbons in the chain, g diethylene glycol, butylene glycol, decamethylene lycol and trans-bis-1,4-(hydroxy methyl)-cyclohexane ^Other groups of polymers useful as components 1 laments of the present invention can be found among he polyurethanes, the polyureas, cellulose esters and :ellulose ethers as well as among the lounds including such polymers as P^0,yc*^yl_{p c} ’ ₁₍?°de icrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and copolymers containing the monomers of these polymers and similar polymers as disclosed . S US Patents 2,601,256, 2,527,300, 2,456,360 and Tvhen/t is desired to remove all sections composed of one polymer composition by dissolution, a solvent to suchAolymer is selected that will not dissolve or have an adverse effect on sections composed of other P⁰¹^ compositions. Thus in Example I which appears below, formic acid was used to remove the polyamide sections from the filament having both polyester and polyamide sections in its cross-section. The extent of dissolution of the soluble portion can be controlled as desired.

Similarly, all sections composed of one polymer composition can be removed by chemical decomposition. Thus polyester sections of a polysegmented filament having alternate polyester and polyamide sections, would be degraded by treatment with hot caustic as would the copolyamide or polyurea portions of polysegmented filaments having copolyamide-polyacrylonitnle or polyureapolyacrylonitrile alternating sections by treatment with Tn thVexamples, the relative viscosity (¾) i-e·, viscosity ! of a solution of polymer relative to that of the solve is used as a measure of the molecular weight. The polyamide solutions contained 5.5 g. of polymer in 50 m . of 90% formic acid and the viscosity was measured at 25° C The polyester solutions contained 2.15 g. 01 tne polymer in 20 ml. of 7/10 mixture of tetrachlorophenyl/phenol and the viscosity was measured at 30 C.

Example I

A spinneret similar to that shown in FIGURES 1 to 3 with 17 orifices was constructed. The plateau 4 was /s in. in diameter and Vie in. high. The counterbore 22 was 40 mils in diameter and extended to within 48 mils of the face of the spinneret. The capillary 21 had a diameter of 12 mils. The lead hole 31 in the upper plate 7 was %₂ in. in diameter was drilled to within 94 mils of the bottom of plate 7. The upper orifices 32 were 9 mils m diameter and were drilled on a circle having a 39.5 mil radius the center of which was concentric with the upper lead hole and with the plateau in the orifice in the lower plate. The spinneret was assembled with a 3 mil thick ^Shpoly(hexamethylene adipamide) of 36 was fed to chamber 9 of the spinneret and extruded to form the tn35

3,350,488 , 5 totor ,o

Justed to si™ _a ratio of^6™ aL™^{mps were} amtfar to FIGURE _{6 me} oblaiid «•ss-seetton. PolyeXSbX to'™ to unpigmemod =® oxide) gfaeorSEX^y ,^etofa«e/l»ly(ethyI. 30/20 iXg* i * 'toposltlo. „f having a molecular weight of 6000 ΤΤη7 ⁸ ^°.^{1 Units}yarns in a hot 5% solution of ^Λβ responding to 102, 104, 106 in FIGURES dissolved and residual ο™ ^rly^uKlii> 4, 5 and 6 are

Example IV

XX XXXX^P°X^^^ 1 to •f Ϊ2/ ’“uS tec ^C' “ “ X 20 ments wound up at 500 v n m Th ^d “ ^composite filaover a 100° C nin λ Λ^Ρ 7 ^{The yarn} was drawn 4.2χ filament is shown in FIGURE ΓαΖΖ“ °/ ^draWnwrapped on a perforate^ metailb ^{Ά yarn was} acetone for 5 minutes The dri d ^and mimersed in «« of . » Su^yX^W_a“ X °™.to

5 g.p.d. so that the yari suffered a 90° !ha °f ?^outtion in the process Thp nhmza change of directo partially fragment lonritudiZi⁶⁸⁸ ,^{caused tbe} filament of the sectors A total of thru ”^{a y a} °^{ng tbe} interfaces a. .bmp edg.X“d X teXE,?' °’» ester and polyamide segments so thf th! °^{f Λβ P}°^Iy' posed of filaments which z. ^^{be yarn was com}and 111 of FIGURE 9 ^cross-section resembled 110 s=i ratXuS'to XX ^d“™ ^y™ «Pletely •XXraXU wS±L ^y™ J “^p« &lt;· tube and placed in 98% formic ^a P^erforated metal for 30 minutes The Ξ ^atJ^{be boiling} P°mt formic acid for an additional s™ ^^{38 tben} Placed in cold ter and dried The ^{Witb wa}‘ cross-section resembled semTnt ilOof ΗΓυκρ7! Mo” 6? .Xf^P:^d’ ‘

1V11 or 68, and a denier per filament of i n Th ^z ’ ^aused as a filling face in the „ · ^{04 L0}· ^The yarn was ^b” - ‘S « feS

Example V tom™ XX^e5 “ IV, acetone and then drawn 2χ over a pin at 88° r Th^ “ nphery of the filaments. ^{Υ δ onglnal pe}'

Example VI •fated periphery. An acetate “·“·« « tea™, ₄

URE 8. ^^dcryiomtnle of shape similar to 1 exSX°_b^P° to ®““«.>>«· P™dueed h, other spinning methods like “Sf ,^tecbmque. Obvioi dry spinning, wet spinning ra ^P?^StlClz!^d melt” spinr In some instances, particiflarlv wh successfi or the solubility of X X^{y when the mel£}ing behawould not Xit p nnV_a X°^neDtS “ ^{a combi}™ methods, a combinXZf S ^C°7°^{nents b}y sim used. Thus, for instance ^{dl miIar} methods can a solution in a high boilinc «ηΐ ^OI“P^onent> can be spun •fate the ofaXXXXeXdX““^<1” Polymer. In these instances Z ^{as a mo1} may be wholly or parfiallv’remnv °^Γ I^asticiz erably by washing them out . “ J^ed, ^sabseil^uently, pr solvents. ⁸ °^{ut by the hel}P of low boili have substantially roZdZossZZ^ ^{this inventil}of the component Howe^wX^ ^S«‘ in the art that by altering tlJ i ^bf apparent to tho final cross-section can*!! conS7/ ^the °^{rifice 21}> « Although square filaments cannot be e^trudeTffl in cross-section which °^{e extr}“^ded, filamen corners can be obtained! bZh * Z^{are witb rou}nde orifices and these in ton would “off °^{f SQUare} °^{r slotte}plane triangles or a combiner °Λ^{Γ segm}ents that ar triangles for example SimibH °^{f Plane and cu}™linea 30 shape of ellipsesZSlform m th ““m _b X” “·™ •Χί “ other moditarta,” “ ^,h<1 ·« to » elrt of the upper orifices 32 Othp number and placement figuration of th!compos£ filaZZ °^{f tb}® the diameters of the unner nrtfi ^PtS Γ^{111 be by var}ying size of the plateaus and/η λ ^S “^{Sed ln reIation} to the ⁴⁰ are extruded through the unnZ Z ^{at wbicb} P°lymers

Plateau. Alteration of tit^71^7^{32 and ov}« the polymers affects the coTfigurattn tht°· 7 ^comP°ⁿent cosity polymer tends to bp _nn«h a ?^btained· A low visby the flow of a 1 ^{mward more readny} > the shape of the segment that if 7^{d hesce ώ}®^Γ® “^encta °'^,he».Xt “ppXX™ »'^d I to example, „ , con. this invention it will be riw?³¹^⁰¹¹ 7 ^tbe filaments of art that other spX^ ^{to tbo}J® billed in the permit the production of fiZL® ^USed',9^ther spinnerets temating segmenTm and ma ^{ribbons having a}lwhich can be split or dissolved n ^sb°^wn.^ln FIGURE 10 filaments. dissolved apart to give sharp-edged mel£ ^aff°^{rdS a C}°^nVenient points in cross-section and of a 1™^ °?^e °^{r more} sharp otherwise attained. ThuZth! inwnff ^{denier tban can be}ductionof sharp-edged filamenZ ^°° ^{permits th}e pro10 or larger. Its greatest utility ?^aV“^{s a den}ier of 0.1 to of 0.1 to 5 denier perΪS’ TlZ™’ 7 ^{the rang}® be used to obtain all manner^novel laments can m fabric handle scroon an™! °^{f DeW and novel} effects by proper selection of the poNmer^ ^C<?X^ering P°wer mentary cross-section. ^{P Υ Γ com}P°^slti°u and filafollowing claim!.^{IS t0 hmited οηΙ}Υ by the scope of the