US2461094A - Method of making lightweight filamentous structures - Google Patents

Description

R. J. TAYLOR METHOD OF MAKING LIGHTWEIGHT 7 Feb. 8, 1949.

FILAMENTOUS STRUCTURES Filed April 12, 1944 w whw M H T m7. M V 0 o O o O o o O m W O .0. 0 o c O o o A f M Y B =1 T W Q 5 Q MN N m N 1 L 7 I I Q l Q I x 1 HI H vIH I o o o e o E E. P k p k r b 9 m [h m a oJ r0 I Patented F eb. 8, 1949 METHOD OF MAKING LIGHTWEIGHT FILAMENTOUS STRUCTURES Robert J. Taylor, Claymont, Del., assignor to American Viscose Corporation, Wihnington, Del., a corporation of Delaware Application April 12, 1944, Serial No. 530,082

Claims. 1

This invention relates to methods for the production of ribbon-like or mat-like structures having a crinkled structure. This application is a continuation-in-part of my copending application Serial No. 479,889, filed March 20, 1943, now Patent 2,399,258, April 30, 1946, and my copending application Serial No. 490,009, filed June 8,

1943, now Patent 2,399,260.

In general, in the present invention, a filamentary bundle containing a mixture of filaments,

preferably of the same material, having different characteristics of plasticity and/ or elasticity is produced and subjected to stretching and relaxation. The bundle maybe ribbon-like or mat-like in character. The filamentary bundle may comprise some filaments which are substantially truly elastic in character and relatively free of any plastic flow under the conditions of stretching, as well as other filaments which are essentially plastic in character so that the stretching effects an elongation which is substantially permanent and is not recovered, or is only partially recovered where a partial elasticity is present, upon subsequent relaxation when the stretching force isremoved. Upon release of the stretching force from such a bundle of filaments, the elastic filaments return to their original length by virtue of their elasticity while the plastic filaments are caused to take a crinkled conformation because of the reduction in length of the elastic filaments.

The mixture of essentially elastic filaments with essentially plastic filaments may be obtained in various ways. For example, one or more filaments may be rendered plastic, such as by the application of heat, solvents, swelling or plasticizing agents, depending upon the particular material of which the filaments are constituted, and they may then be associated with one or more non-plasticized filaments ofthe same or different material with or without twisting. Again, filaments which are completely elastic and set up may be associated with freshly spun and. still plastic filaments of the same or different material. In this latter case, the association may occur shortly after the plastic filaments leave the spinneret. Again, one or more filaments of small diameter may be spun simultaneously with one or more filaments of large diameter (which may be hollow, if desired) and passed through a common coagulating bath, from which the associated filaments emerge in different plastic and elastic conditions and are subjected to stretching in that state. This may be accomplished by having a single spinneret containing both large "and small orifices, or by having a plurality of spinnerets oneof which has large orificesand the other small orifices, from which different size filaments may be spun. Again, the same result maybe the orifices.

These materials may comprise difierent filamentiorming components so adjusted that upon emersion from the coagulating bath the different types of filaments exhibit different characteristics of plasticity and elasticity, in which state they may be stretched. A plasticizer may be incorporated in one of the spinning materials for imparting to the filaments obtained therefrom a rubber-like elasticity, especiallywhen vinyl resins are used. Also, the materials may comprise the same filament-forming component but use difierent solvents which are removed from the extruded filaments at different rates, thus assuring differences in elasticity and plasticity at the time of subsequent stretching. For example, a copolymer of vinyl chloride and vinyl acetate may be dissolved in dioxane and extruded through one spinneret, while a similar solution in acetone which is more volatile than dioxane may be extruded through another spinneret. Thedifferences in plasticity and elasticity at the time'of stretching, in the latter system, may be accentuated by extruding the solution in dioxane through larger holes than those of the spinneret through which the acetone solution is extruded. As an alternative to the use of separate spinnerts in any of they cases just mentioned, a type. of spinneret or jet may be employed which'is provided with suitable partitions back of the spinneret face, for dividing that space into separate regions which communicate withseparate lines to difierent spinning supplies entirely, or through separate pumps to a common spinning line, so that the spinning material supplied to one of the regions back of the spinneret face passes through the orifices associated therewith and that supplied to the other region'or regions back of the spinneret face is extruded through the other orifices in the spinneret, which may be of the same or of different size than the orifices associated with the other region. This type of spinneretis the subject matter involved in the co-pending application of Robert J. Taylor and Wesley L. Webb, Serial No. 492,702, filed June ments, the small filaments will show the most crinkling in the product. W here, however, stretching is performed upon a mixture of freshly spun filaments of both large and small diameters, the small filaments being completely set and the large filaments still plastic; the large filaments will show the most crinkling in the .product.

The stretching may be performed by anynf the known means heretofore employedfor stretching yarns or yarn-like bundles of filaments. Thus the bundle may be passed about a series of positively driven rolls in succession, at sesame- --of said .TheseandalternatiVe arrangements are illustrativelyrepresented in the drawings hereinafter, inwhich- Figure 1 is an elevation of an arrangement adapted toharidletheweb-like filamentary bundles Figure 2 is another illustration of an arrangementfor manipulating the web-like bundles;

Figure 3 showsia cross-section of one form of spinneret that may be used; and

Figure .4 is.. a face yiewof a modified form of spinneret that maybe usedin the invention.

Eigure 1 shows .a ..eoagulating bath? with a a second funn el; guide H! is positioned in the bath near the point of emergence of the filaments therefrom. The. filaments, in the gformcf a weblike sheet with the filaments arranged either parallel or haphazardly intercrossed therein, proceed through a seriesofsseparate conveyor systems ll l-2, !3 in.succession, and then to-a suitable take-updevicel l. onwhichthe sheet may .be collectedwith or without tension. Each conveyor device comprises a pair of superposed chain sections comprising :interdigitating cross-pieces or girtslt "which seize the webrlike sheet and hold it. in zigzag coniormation while moving the sheet through the device. This particular device forms no part of this invention and its construction maybe-that of the device disclosed in my copending application Serial No. 530,683, filed April 12, 1944, patented October 2, 1945, No. 2,385,894. The second conveyor system I2 is operated at ahigher-rate of speedinorder to-effect stretching of thefiight ofthe web-likesheet extending betweenthe two systems II and [2.

The web-like sheet aiterleavingthe second conveyoivsystem 'l- 2 may'.-be allowed to relax in its flight therefrom tothe nextconveyorsystem l3, which may be utilizedfor carryingthe sheet during wettreating or-drying thereof. From the latter 'conveyorvsysteml lfi, the sheet may be continuously transferred .-to a suitable take-up device, such'as a drum whichmay be operated while partially immersed in a liquid, such as water inert to thefilamentatoobtaina wound band of intricately intercrossed filaments of the type i cles in my mien-pat nt 39 s my prior application, the wound band, after col- 4 lection, may be slit in the general direction of its width andniay then be dried. {The dried band is then seized at its four corners (or at numerous spaced points along each of the two sides which extend in the same general direction as the length of the filaments) and while maintaining it untier-tension along its length between the points .of seizure, it is stretched out in the direction of its width. This stretching along the width is accompanied .by a surprising expansion in the thickness of the material.

FigureZ-showsan arrangement similar to that oflzfigurel in that the object is to produce a weblike sheet of filaments comprising both large and small diameters. The spinneret l6 may beof .the form shown in Figure 5 and the filaments pass throughguides of funnel like characters I"! and i3, then about rolls 119,10 and '21, which are arranged to enact-transfer of the welrlike sheet as a sheet out of'the coagulatingbath 22 into a second bath23 within which the filaments maybe stretched as a sheehsuch stretching being effectedby virtue of the fact that the web-like sheet passes aboutcthe peripheries of another set of three rollers 24, 25 and '25, driven at [higher speed than the first set. The second setof rollers serves also to remove thev filaments as a web-like sheet out of the second bath '23, andtolirnmerse them into a'third bath 2'! within which they proceed through a guide 28 to a suitable take-11p device 28 whichmayhe partially immersed in the liquid of the third'bath. By maintaining the flights oi filaments extending'between the two sets of rollers andbet'ween the second set ofv roll- .ers and thetake-up device under liquid, the loss of. the web-like character of the filamentary bun die is prevented, even though subjected to stretching during such free flights. 7

Figure'li-illustrates in cross-section a form of spinneret in which one spinning material may be extruded through certain of the orifices thereof and another spinning material extruded through certain other orifices thereof. To accomplish the space backof the spinneret face 30 is dividedbya partition 3i into two or more separate regions (two such regions A and B being shown), each of such regions communicating with a separate setor group .of orifices 32and 32', .whichmay .or may not .be of thesame size. iTheregionsA andBinto which the space back of the .spinneret is divided, is then associated withseparate .spinning solutions by means of separate feed lines stand .3llrespective1y, Of course, if it .ismerely desired tousea spinneret having orifices allof the same sizeand a single spinning solutiomthe regions ,backcf the spinneret face may beconnected through the separate lines 33 ande ii and separate pumps .to a common supply lineforthe spinning solution and then two pumps operated at difierentspeeds to pro- .duce differently sized filaments.

In Figure l the. spinneret=35 haslarge orifices 36 andsmalhorificesal heterogeneously intermingled. .The-use-of thisspinneret causes the 24:1nches is capable of completely setting thesmall diameter filaments without destroying the elasticity of the larger filaments Spinnerets of either of the types shown in Figures .3 and 4 may be used in eitherof the arrangements shown in Figures 1 and 2.

Besides producing wound bands ofcrinkled web-like filamentary sheets, expansion of. the wound bands obtained by the arrangements of Figures land 2 in accordance with the procedure disclosed in my Patent 2,399,258, produces a novel light-weight filamentous product useful as a heat insulation material, a buoyant material, for aerosol filtration, cushioning material and the like. Such products may comprise filaments having large diameters ranging from about microns to 300 or more microns in diameter, and any desired proportion of small diameter filaments ranging from about 1 to 10 microns, or theymay comprise any combination of small and large sizes. Because of the conditions and circumstances under which the wound bands are made in accordance with the present invention, the cut-.

ting of such a wound band transversely of its annulus and expansion transverse of the width of the bandgives rise to products'in which either the small or the large diameterfilaments therein crinkliness becomes more uniformly distributed throughout the product.

In general, the expanded mats made in'accordancewith this invention and the disclosure of my prior copending application comprise criss-cross filaments lying substantially in generally parallel and more or less undular planes, so that the mat is substantially laminar in character. The space occupied by the mat is extremely subdivided by the criss-cross filaments extending in undulated planes substantially at right angles to the thickness of the mat and to the fact that the lattice work formed by the filaments in one web is out of alignment with that in adjacent webs lying generallyiparallel thereto. The extreme intricacy ofthe network is particularly noticeable when a large number of filaments of extremely fine diameter and a relatively small proportion of large diameter filaments are converted into the prodnot. The superimposition of web on web of such irregularly arranged intercrossing filaments with the additional waviness in' the individual filaments :produces a filamentous mass having an intricate network disposed across the path of travel in the direction of the thickness of the mat. All filaments in one web, lamination or strata do not contact all filaments in the next adjacent at the, pointswhere they appear. to crossas the result of the distortion caused by the stretching.

th contraction caused ness and. crinkliness in those filaments which were in a plastic condition when the mixture was subjected to initial stretching; The result is that, while all of the filaments in the product extend generally from one side thereof to an opposite side; or edge'thereof, many of the filaments are infa highly crinkled condition as the result either of...

theinitial stretching of the mixed plasticand elastic filaments or of the subsequent stretching:

of the'band to expand it into theform of-a mat,

or, in .some cases, as. the result of both factors. The-mats producedin accordance with, this'in-.-.

vention are characterized-by.essentially the same structure as'in my' prior copending application,

except that amixture of diiferent sized filaments:

are involved in the present mats and either the larger. or the smaller filaments therein or both the large and small filaments, are characterized by-increased waviness and .crinkliness, as-compared to the mats of myearlier application.-

While preferred embodiments of the inventionhave-been disclosed, it is to be understood that changes and variations may be made without departing from the spirit and scope of the inventionas defined by the appended claims.

I claim:

prising' continuous filaments in a plastic'condition mixed with continuous filaments in an" elastic condition, collecting the sheet as such' while still wet in the form of a multiple-layered" winding, severing the windin across its width, .drying the relaxedwinding in the form of a band, and stretching the dried band out in the' direction of its width while permitting it to expand in thickness. I I

2. A method of producing filamentous products comprising the. steps of stretching; in a direc tion'genrally longitudinally thereof, a wet filarmentary bundle of web-like sheet structure com prising continuous filaments in a plastic con dition mixed with continuous filaments in an elastic condition, collecting the sheet as such while stillwet and under tension in the form of a multiple-layered winding, serving the wind-' ing across its width, drying the relaxed winding' in the form ofv a band, and stretching the dried band out in the direction of its width while permitting it to expand in thickness.

3. A method of producing filamentous products comprising the steps of stretching, in a direction generally longitudinally thereof, a Wet filamentary bundle of Web-like sheet structure comprising continuous filaments in a plastic condition mixed with continuous filaments in an.

elastic condition, collecting the sheet' as such while still wet in relaxed condition in the form of multiple-layered winding, severing the winding across its width, drying the relaxed winding in the form of a band, and stretching the dried band out in-the direction of its width while permitting it to expand in thickness,

4;. A method'of producing light-weight filamentous products comprising the steps concurrently forming in a common precipitating medium a mixture of wet continuous filaments having different rates of setting up, associating said filaments in a common bundle of web-like sheet structure, stretching the bundle in a direction generally longitudinally thereof while at theelo eat d tic? filaments when released. causes additional wavizeergeee 1eastone -ofthe -=fiiamentsthereir'r'is -essentiel l y elastic in character-end at least=one oth'ez is still -essenti allyplastieeharaetezacollecting the sheet as sueh while still wet in the --form---of a multiple-layered winding; severing the -winding aeross --itswidth, drying the relaxed winding inthedor-mof a band,- and: stretching :the dried: bandout in the-direction offiitswidth while: perm-itting 'it -t0 expand -in: thickness;

52 A) method of producing lighuweightdilae mentous: products compr-ising :the steps: tot-:3 con-1- ourrentlm forming. inat common precipitating medium mmixture of wet: continuousaxfilamente havingadifienentarates of: settingaup; associatingsaldz'filaments. in a: common ,:bundleeof; weblike sheetistructure, stretchingzthellbundle imd-aaedie reotion: generally longitudinally thereof while at; least :one :of the. filaments. therein; essentially?- elastic inlcharacter; end at: least.v one other still: essentially plastic. inicharactezz; colleetingthe; sheet; as sucmwhile ;sti1l.uwet:v andmnden tensiom in theiormot:a.mu1tiple-layened windinasevere ing-itherminding;acrossnitsiwidth; drying the arelaxed winding-.imthe form of azbandbandvstnetehrn ethe drieduband; out innthe-i direetion: of, its width: Whilwpermittflng. it; to expand, inythlck ness.

6. A method of producing light-we'glitefilamenteus; products; comprising, the steps; ofiiconcugxentlyforming; in: a. common precipitating; mediumsasmixtune, of; wet. continuous; filaments having id-ifferent rates of setting up, associatingsaiclefilamentstina. .common; bundle, of. WQhEli-KQ: sheet; structure; stretching theybundle in a; die;- reetio'nz generallylongitudinally thereof. while-at; leasteoneloi the; filaments t therein is essentially elastie in; character and at least one othen-is. still; essentially plastic in character,- eolleeti'ngithe sheet-as such while still wet and ,in. relaxed com-(l dition invtheformuoi a multiple-layeredwinde ing, severing the winding ac tossits width, dry,- ing therxelaxed winding in the, form of. a. band; andgstretching the dried bandw'lout in tiomof-eits Width. whileipetmittingflit.tQeXPandJm thicknesses 'YLlTAe method of: producing lightweight. filer. mentousvpmduets .comprising the.steps-. .of'c0n. curxently formingin a, common precipitating mediums. mixture .of wetcontinuous.filaments; of. a, icogolymen of. ,viny1,.chloride. and .vinyl acetate. haying difierent, rates of setting.,up,, associating said filamentscinma) common b,undle. ;of. web..-lil-ie sheet; steucture in a,v direction. stretching the bundle in afldirlectionz generally, longitudinally thezeoflwhile at. least one oi-thetfilamentst therein is essentially elalstiein. charactenandat leastlnnem other is,sti1l essentially plastielintcharacter col-e lecting'r the sheet assuchwhile still wetandlunder tensioniin the formnofwaemultiplerlayenedewinde ing severing the winding ,across its width, dry, mg the relaixecl'wiridihgin the ,formpof a handy and stsetching the. ,driedmband. outin .themdinec; tionilofuitslwidth while permitting. .itto expend.

infthiekness 8h!method,.of; ,preducing aelighte-weight,filarmentions;:productpcomprising: the steps 50f:- c,on.-1-- currentlyforming a, comznom pnecipitalting; medium-:a;-mixtureof wet, continuous. filaments of aeeopolymee of "vinyl; chloride; andqvinyl acetate:

cemp isingfilaments; of largediametemanddile 70* meme; of: smallezj: diameter; which: set tupzmorex rapidly: than; the :1 larger: filaments; Y associating;

a: saidl'fila'ments-in ex common b'undle ili'a diiieetiiin generally longitudinally =thereofi bf- Wen -like sheet stmeturerstnetehing the-bundle whileet-leastwne of the 'small filaments theeeiIi-is essentiel'lWelzts''-- 51 tie- 121* 4 character and-at least? one of the lrge 1e stretching thedried 'band butr in tfie=difeetidn-=of= its width while pemnitti-ng it-io-expand izi thiok nessw r 9-? mmethod iof producing aalight weighfgfila mentous product comprisingthestps ofiasso like sheet structure a mixture ofawet continuous filements responding differently to pla'stioizizig media; subecting ttie bundl'e'whil =-still in th'e for-m1 of av-webdikesheet structure 'to-a plaistioiz ingxmediumw then: stretching the bundl im-a 'dii-" reetimn general-1 y" longitucli'nally= thereofi whilestalll inlwebdike -form endwhile at' -l'east one filelment thereim is in aeplasticl: :cendition and? at; least? oneuother i filament i therein iS -ili a sub'stantiallifi elastieaconditiony collecting the sheet whil' still wetiiasssuchezinnthe form: of; a -multipleslayeped z winding; severing the 'win-dihg across -it's ewidtfitdrying therelaxed winding*iri th'e40mmof-euhieladi andsstretching thezdried band-out in thedii'ectiom of}: its; widthzzwhiles permitting: if}? tozexpandi in thickness;

10..,A-.:i.metl1od:i of: producing-:- a; light-weight? filamentousaproduct comprisingthe stps of asso stating in a lzcommonfilamentary-bundle:-offlweh like.hheetfstnuctureeazmixture o wet Bontiii-uons filaments ofrra'zcopolymer of fvinylohlol i'de' enr1 vinsrhaeetate' which are: of d'rffeventisizes "and" thexeby: are .edifierentlyr: affecteda-by plastieizing'; med-le subj eating ztheebundleeto a plestitiizihg w medihm whilemeintaining it imslieet:formati'on';

stretching theimebelikexsheet im'w diPectiUnYgeH enally longitudinally:memoir-while at least-"0211:- filamenttithenemzis;imaz'plastie conditronraml at least eoneaother filamentrthereiriaiaiheasubstane 4E5 tiellywelastimconditien; collecting-:5thewslieetziesr bandeoutdn:thegdirection; of: its widtlirwh-ile perwmittingeit tozexpandjmthiokness.2

ROBEBTE'JZ TA: "OBI-r REEERENCESeGITEDp.

The -following references are 'of'-recordfin*the file -of this patent? UNITED. STATESePA-TENTS Nnmh'em Mme Dime?- 6G? 845658. 79? \Wddetl Mair:-'12'; 1907- 1,993,8fl? Kzoch't Mam--12; 1935 2;;165251 i Taylor. Jan. 12, 1937 211,558.93: Eisenhut etelteenfl Apr. 1851939; 21811353.; Boedding'haus Nova 21"," 1939? Taiylors; Aprz BUi-IQ L'G Certificate of Correction Patent N 0. 2,461,094 February 8, 1949 ROBERT J. TAYLOR It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 50, for the word serving read severing; line 62, after the word wet insert and; line 63, after of insert a;l1ne 69, after steps insert of column 7, line 53, before stretching strike out in a direction;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 20th day of December, A. D 1949.

THOMAS F. MURPHY,

Am'stant Uommz'm'oner of Patents.

Images