US2980362A - Thread package wound from continuous filaments of a synthetic linear polymer - Google Patents

Description

Apnl 18, 1961 GODDARD 2,980,362

THREAD PACKAGE WOUND FROM CONTINUOUS FILAMENTS OF A SYNTHETIC LINEAR POLYMER Filed March 6, 1956 v PRIOR ART T F 92 IV 55 In ventor l diy Goa (Id rd 6014014446 W V I Aito neys THREAD PACKAGE WOUND FROM CONTINU- OUS FILAMENTS OF A SYNTHETIC LINEAR POLYNIER Sidney Goddard, Abersychan, Pontypool, England, as-

signor to British Nylon Spinners Limited, Pontypo'ol, England Filed Mar. 6, 1956, Ser. No. 569,852

Claims priority, application Great Britain Mar. 17, 1955 Claims. (Cl. 242-176) The present invention relates to thread packages wound on bobbins from drawn continuous filaments of a synthetic linear high polymeric substance showing visco-elastic properties, such as nylon. That is to say the inventionis concerned with the shape and formation on a bobbin of the mass of such drawn filaments. These filaments, although capable of being stretched somewhat and resuming their original length, only do so over a period of time, rather than more or less instantaneously, and, after the drawing operation in whichthey are produced, they relax slowly from the length to which they have been stretched, to a length slightly, but significantly,'less than the former length. It is the normal practice to wind such filaments, whether as single filaments, known as monofilaments, or as groups of twisted filaments, known as multifilaments, on to a rotating core, usually cylindrical in shape, which for convenience, but not limitation, will be known herein as a bobbin. The filaments are traversed axially of the bobbin by means such as a traveller revolving within the ring of a reciprocating ring-rail, and the movements of the traverse mechanism during the time of winding govern the shape of the wound package on the bobbin. Normally, such filaments are wound into cylindrical packages or into packages with a tapering extremity or extremities, depending on what further processes are to be performed on the filaments. For instance, if it is desired subsequently to unwind the filaments over one end of the bobbin, it will be desirable to have the shape of the package at that end tapered. Furthermore, the existence of the tapered end-portion of the package obviates the necessity for a flange at that end of the bobbin thus reducing the cost of the bobbin and precluding any of the difficulties inherent in winding thread satisfactorily between two flanges. if both end-portions of the package are tapered nothing more than a cylindrical tube is required as a bobbin, which is a considerable saving when the number of bobbins under consideration runs into millions, and no alignment of the traverse.mechanism with the bottom flange is necessary in this case. Thus it will be seen that a satisfactory single or double-taperpackage is not only an attractive proposition from the economic point of view, but also attractive from the point of view of the simplicity of. the winding and unwinding operations.

With drawn continuous filaments of a synthetic linear high polymeric substance showing visco-elastic properties, however, we have found that it may occur that, owing probably to the compressive force exerted after a drawing assassz Patented Apr. 18, 1951 formed on them to orient the filaments to increase their tenacity. The phenomenon will arise, if, as is normally the case to bring about the formation, there are less layers of yarn at the tapered end-portions of the package than in the middle body portion, because, then, filaments at a given same distance from the bobbin surface will be compressed by a different amount depending on whether they are in the body or end-portion of the package, owing to the differing number of layers of filaments outside them.

This phenomenon of the differing physical characteristics of the filaments in difierent parts of the wound package can be sufficient to prejudice the acceptance of such filaments in certain uses. For instance, the differences in relaxation brought about by the phenomenon may be most undesirable. This is particularly the case with filaments of nylon which have been wound in the normal. manner, at the end of the drawing operation, by means of a reciprocating ring-rail working in conjunction with a pluralityof rotating vertical spindles carrying bobbins, wherein the upper end-portions of the wound packages are tapered by causing the ring-rail to traverse continuously over the body portions of the packages, but only in cycles over the upper end-portions in such manner that the nearer the noses of the packages are approached the less coils are wound. Such a formation is readily brought about by a succession of gradually increasing and gradnally decreasing strokes of the ring-rail, the stroke never falling belowa certain datum marking the tops of the body portions of the packages, and rising to momentary maxima in each cycle, marking the noses of the packages. It will be apparent in this formation that, over a given length of filament wound during the completion of a traverse stroke, the compressive forces experienced by the filament will vary according to its position in the package, i.e. whether in the body portion or in the tapered endportion. Such length of filament is comparatively short, and is such that, when the filament is pirned directly from the bobbin and used as weft in a woven fabric, the difierences in the physical characteristics of parts of it give rise to visible differences in lustre in the fabric, due to difierential relaxation, which take the form of intermittent lines or bars, where the fabric is tighter than at other parts, known as weft barre. The insertion of a fairly high degree of twist before pirning will reduce this elfect, but such high twist is not always desired in weft yarns and in any case, it demands that an extra operation be performed.

Heretofore, therefore, the use of singleor doubletaper packages of oriented nylon filaments has only been possible at the expense of fabrics with lustre diiferences operation by the wound loops of filaments on to those loops beneath them and ultimately on to the material of the bobbin, a difference in shape of the parts of the filaments of a synthetic linear high polymeric substance showing viseo-elastic properties, immediately after a drawing operation has been performed on the yarn,

wherein the yarnis wound into a package on a bobbin whose winding surface is of substantially cylindrical shape by means providing a gradually increasing traverse stroke residual relaxation) in those respective parts. This fea v I ture is' one which had not been met before the advent of these filaments of synthetic linear high polymeric sub.- stances such as nylon, which retract somewhat slowly but with greatforce on thebobbinon which they are wound .afterthe drawing (or stretching) operation has been'pen from a minimum .strokeat the start of winding, to a 'maxirnum stroke at the completion of winding suchthat the'taper angle at a tapered end of the bobbin as hereinafter defined does not atv any time during winding exceed a 7 30. The invention alsocomprises packages so'wound, in which either or both endportions of the package, are

a g 3 tapered. The taper angle of the package is defined as the angle between a plane at a point on anend-portion tangential to, or lying along, the surface of the end-portion F at the base thereof. Yarn Y is wound .on the cylindrical portion of the bobbin between the flange and a point below the cap C of the bobbin, the upper end of the package being tapered at T, The figure shows how the traverse varies throughout-the winding, the upper limit a of the traverse stroke varying between a andfiaccording be experienced in unwinding, even supposing that it is a P s ib a ca h x mum per. n le atany time during 'windingis specified above, asflitis P obable that the surface of a tapered end-portion of the package will be made up o f parts of varying degreesof curvature, but

it is the'maximurnangle at anv'point andat any time, which is critical for stability. 'Parts 'ofthe tapered portionmay, in fact, beconvex, and'parts concave; andrthe taper 'angle-will'almost certainly always vary during the i d a f e t st gesi h eo e 7 It is also, of-course, ,trugto say that the minimum taper angle. (measured after winding has proceeded sufficiently for such to be measured with any accuracy) thatis essential for the most beneficial results to be obtained from the invention will also be a relevant consideration. ,However,

to regular cycles 5; Of thetraverse. H H t .7

In Figure 2, a similar bobbin is shown withtyarn wound upon it with a traverse which gradually increases from a stroke a at the. beginning of the winding 'to alstroke b at the completion of the package a V In Figure 3, the overlapping of succeeding layers of yarn is shown and two taper angles, (2 and :6 are shown referred to above, it must be made clear that this expres in practice, as it is always desirable to wind the maximum 7 amount of yarn in a package, itis clear that there will be no incentive togwind packages with very small taper Q angles, eg; of the order'of less than 10?. If it isattempted to'windta full package starting with such 'a small taper angle, however, it must be made clear that ,difi'iculty with 1 'sloughing will almost always occur,'as it will be'necessary' i some pgint, exceed 30.'- J e V i Thepreferredlimits of taper angle can be stated to be I is coveredby an equal number of further layers of filainents, so that any variations in :the physical characteristo so lsteepen'thefangle of, the nosein-orderto accommoo ate'therequired amount of yarn that the angle will, at

tics of the filaments do not occur within a layer i.e. in 1 relatively short lengths otthe filaments. t

Furtherr'nore, we have found that any differences be-' tweenthe physical characteristics of filaments lying nearer 7 side of the' package, Ealthough not so: detrimental .to the t fi a en s- M9 1a bob n fi e x na lyl h pressible sleeve or'on to a bobbin which is itself made of for difierent points on the tapered nose portion during the winding; 'Thi's figure is partially sectioned, to illustrate a wood center 10 in bobbin B, enclosed by a compressible rubber sleeve 12. I

Where synthetic linear high polymeric substances are sion is used to describe not only'homopolymers, but also co-polyniers and inter-polymers, which can be formed into fibres andfilainents, and which areiproduced as a result of chemical synthesis] Examples of such polymeric'subsome; are nyloh'andfIerylene" (Reg, T.M.) polyester The means to provide thegradually and progresively increasing traverse stroke maybe of the general kind well-'knowninthe' textile art, suitably modified, and the inrea eer stroke 'may; either be at a constantflrate or a fate varying with the length of the stroke. YSimilarly, the time of each'traverse stroke may be 'constant'throughout the whole winding, or it 'rnay be'variecl with the length of the stroke, for fexample, proportionally to "the same.

- Again the rate of traversing may be nonunifcn'rnithro ughout a'strolejfor instance, the traverse may be accelerated at the points of reversaljof direction. a a Should it befdesired to'use a compressible sleeve, it may be ofthe order of 30 thousandthsof antinch to 200 thousandths of an inch thick, and it must not: be' too easily compressed by the strong filamentstnors'o hard that the filaments make littleimpression on it, or :it will not have the desired eifect. Certain typesoi hard rubher and cardboard have provedisatisfactory, and acomthe inside of the package and those lying nearer the out-o f bination i:if l:ta 1 r cl and fmore compressible rubber in a sleeve, with the former on the outside toprevent em- 7 bedding hf the firstrlayeror layers of filaments,- is end- I a gently suitable. A maple bobbin has been found suituse ofthe'filamentsg'may largely be obviated by-winding i.

'a material censiderably more compressible than a metal; This expedient will also ensure that filaments Wound next to the surface of the bobbin can contract equally to those wound upon other layers offilarnents, lThe' presentin 4 .j vention, therefore, further comprises a method of winding yarn, consisting of'a single filament or a plurality of filamerits of a synthetic linea high polymeric substance showingvisco elastic properties, immediately after a draw ingoperation hasibeenperformed thereon, wherein the yarn is wound intp afpaekage on a bobbin'ithe winding surface of which is substantiallycylindrical'inflshape-and; i isyrnade' or compressible materialgby means providingaj gradually-increasingtraversestrokeas hereinbefore de- I? jscribed; and also comprises p f The f llowing d seriptionfgivenwith; reference to tih e 7 one mpa'nying drawin'gsldcmqnstrates how the invention 7 H I f a sso wq di w sh Ieitherior both'end-portionsaretaperegl,' 1 5 Fee: a o

r a len t if 5 ace i 1 able'foriuse s a bobbin of more compressible material than thatoi say, aluminium.

the yarn such as might causebarre',

' iis fl j V cylindrieal" bobbin anep a' fr e" i r01 6: imparts It is' o en desired to insertaj lowdegreeiof twist, say

Qontiniious filamentsliof ,denier ayie multifi'lament yarn, with ,a twist of am; per inch a 4 or ie e'wq o after the spun-filaments hadlheendraw The same yarn as in Example 1 was drawn at a ratio of 4.8 and at a speed of 425 ft./min. and wound up at a spindle speed of 5,100 r.p.m. The traverse stroke increased uniformly, as in the previous example, from an initial length of inches to a length of 7 /2 inches, during which time a package weighing 1 lb. was produced having a taper angle of 17 for the conical nose portion.

Example 3 45 denier nylon continuous filament yarn was drawn at a ratio of 3.31 and at 1,250 feet/min. and was wound up at a spindle speed of 7,600 r.p.m. according to Example 1, save that the traverse stroke was increased from 5 inches to 7 /2 inches and that the ring-rail was traversed in 20 second cycles. A 1 lb. package of yarn was thus produced with a conically tapering nose portion having a taper angle of 16 48'.

Example 4 60 denier nylon multifilament yarn was drawn at a ratio of 3.17 and at 625 feet/min. and was wound up at a spindle speed of 6,000 r.p.m. according to Example 1, save that the traverse stroke was increased from 5% inches to 7% inches during winding, and that the ringrail was traversed in 10 second cycles. A 1 lb. package of yarn was produced with a conically tapering nose portion having a taper angle of In the above Examples 2 to 4 the propensity of the yarn to exhibit barr in fabric woven from it was reduced to below the visual level in a dyed fabric, and this despite the fact that the yarn was woven as weft in its substantially untwisted /2 turn per inch) condition.

What I claim is:

1. A yarn package consisting of a bobbin and a drawn single filament or a plurality of drawn filaments of a synthetic linear high polymeric substance showing viscoelastic properties wherein superposed layers of loops of the yarn are wound upon said bobbin substantially immediately after the yarn is drawn, each layer extending by a small amount beyond the preceding layer at either or both ends of the package; said package containing at least one pound by weight of yarn and wherein the axial distance on said bobbin covered by the longest layer of loops of yarn is not substantially greater than 1 /2 times the axial distance covered by the shortest layer.

2. The package defined in claim 1 wherein the taper angle is between about 15 and 20.

3. The package defined in claim 1 wherein the surface of the bobbin on which the yarn is wound is defined by a compressible sleeve.

4. The package defined in claim 1 where the surface of the bobbin on which the yarn is wound is made of a material more compressible than aluminum.

5. The package defined in claim 1 wherein the taper angle at the ends of said package does not exceed 30 for any layer of the package.

References Cited in the file of this patent UNITED STATES PATENTS 2,256,150 Mallory Sept. 16, 1941 2,379,813 Loveridge et a1. July 3, 1945 2,407,358 Whisnant Sept. 10, 1946 2,512,951 Luther June 27, 1950 2,554,537 Moss 'May 29, 1951 2,764,363 Stammwitz Sept. 25, 1956

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