US3477219A - Apparatus for making yarns of artificial polymeric material - Google Patents

Description

NOV. 11, 1969 LLlAMs 3,477,219 APPARATUS MAK YA OF ARTIFICIAL POLYMERIC MA IAL Filed May 7, 1968 Inventor A llorncy United States Patent 3,477,219 APPARATUS FOR MAKING YARNS 0F ARTIFICIAL POLYMERIC MATERIAL Roy Alan Williams, Pontypool, England, assignor to Imperial Chemical Industries, Limited, London, England, a corporation of Great Britain Filed May 7, 1968, Ser. No. 727,284 Claims priority, application Great Britain, May 10, 1967, 21,671/ 67 Int. Cl. D01h 7/02, 13/26; D07b 3/02 US. Cl. 57-59 6 Claims ABSTRACT OF THE DISCLOSURE This application relates to the manufacture of yarns and describes an improvement over application, Ser. No. 465,080, filed June 18, 1965.

More particularly the present invention relates to an apparatus for manufacturing yarns from continuous filaments which simulate yarns derived from staple fibres.

The term continuous filaments as used herein refers to filaments which are of an indefinite length and which in the practise of this invention are continuously supplied by extrusion from a source of polymeric material.

In said application, Ser. No. 465,080 there is described and claimed, inter alia, apparatus for manufacturing yarns which comprises means for extruding a polymeric material into one or more continuous filaments, a traverse mechanism located some distance away from the extrusion means and arranged to impart a reciprocating movement to the filament or filaments, a body arranged to rotate with a peripheral speed sufficiently high to apply tension to the filament(s) and to assemble the filament(s) around its surface in the form of a sleeve, means for withdrawing the sleeve from the surface of the body at a slower speed than the peripheral speed thereof, means for everting the sleeve simultaneously with, or subsequently to, its withdrawal from the surface, and means for collecting the yarn so formed. The application further describes a convenient form of the apparatus whereby the yarn sleeve may be simply and successfully everted. This comprises a rotatable body which contains an axially-extending passage and the sleeve is everted by pulling it therethrough in a direction opposite to the direction of forward movement of the sleeve as it moves along the surface of the rotatable body during its withdrawal. In the same apparatus, the means which operate on the sleeve to withdraw it from the surface of the body may serve to pull it through the axially-extending passage and may further serve to collect the yarn that is formed.

The practise of the above invention and the use of the apparatus disclosed and claimed by the aforementioned specification provide means for the manufacture of a variety of continuous filament yarns and it is the addition to this variety, of continuous filament yarns with superior properties, with which the present invention is concerned.

For any given arrangement of operating conditions the final properties, behaviour, appearance and structure of the continuous filament yarn in question will vary according to the chemical and physical characteristics of the ice continuous filaments used in its production, while at the same time different operating conditions in the case of any one type of continuous filaments will likewise give rise to an assortment of yarns.

Although the aforementioned invention possesses sufficient flexibility of operation to meet the demands for yarns possessing different properties, the precise control of these properties over extended periods of time is often difficult and consequently it has been found desirable to modify the apparatus described above so as to meet the precise and accurate control of yarn properties that is often necessary.

Obviously, any further understanding of the mechanism of the aforementioned invention could well enhance its versatility and it is from an examination of the fundamentals of this invention that the present invention has been made. Extensive investigation of the operation of the invention and the manner by which final yarn properties may be influenced has led to a new appreciation of the rotatable body or godet around which the yarn sleeve is assembled before its withdrawal. The profile and surface characteristics of the godet used seriously affect the manner in which the yarn sleeve is laid and built and in turn, therefore, determines to a substantial extent the properties of the yarn that is finally produced. Variation in profile and surface alone may be sufficient to determine the final use to which the yarn may be put.

Thus, the structure and formation of the sleeve that forms on the rotatable body depends significantly upon:

(a) the actual shape or profile of the body and, (b) the nature of the surface upon which the yarn is laid and the sleeve later built.

Although the rotating body may have a variety of shapes, it is preferred that it should be profiled so that there is an overall taper in the direction in which the sleeve is moved therefrom, for this facilitates the withdrawal of the sleeve as a coherent, integrated structure which is important in conveying to the yarn some of its characteristic features and properties.

Among the diversiform rotating bodies that have been found to influence yarn properties are those whose crosssectional shape, when viewed in a direction substantially coincident with their axes of rotation, may be described generally (no sharply defined edges i.e. with rounded apices) as triangular, square, rectangular, rhomboidal, parallelepipedal, trapeziumoidal, trapezoidal, pentagonal and like regular sided figures, circular or elliptical. Such bodies may possess an essentially conical, hemispherical, parabolic, hyperbolic or logarithmic cross-section when viewed in a direction substantially at right angles to their axes of rotation. Also, any figure may be truncated so as to either increase or decrease the minimum distance between its axis of rotation and circumference,

Although it is preferred that any such figure should possess an overall taper from one end to the other, the gradient of the slope may vary over the taper and may even be reversed in places.

As well as effecting useful control over the final structure and properties of the continuous filament yarns by changing the shape of the rotatable body, changes in the nature of the external surface upon which the yarn sleeve is built will similarly influence yarn structure and properties.

In this respect the nature of the surface may first be varied by employing different materials for its construction such as metals, plastics or ceramics which in turn may be surface modified so that they very from smooth and continuous to rough and discontinuous, depending on the type of filament or yarn that is used and the requisite yarn structure. Surface roughness may take the form of slight indentations, scratches, whorls, ridges,

projecting teeth or hooks or other protrusions which may run either at random or in a pattern, or more substantial irregularities such as deep cuts, troughs, rifts or surface projections such as might form a nodulated surface which likewise may occur at random or in a pattern over the surface of the godet.

Such surface effects may or may not follow the general profile of the rotatable body in depth or height.

Thus, the present invention provides an improvement in or modification of the apparatus described in said application, Ser. No. 465,080 wherein the body that is arranged to rotate with a peripheral speed sufficiently high to apply tension to the fi1ament(s) and to assemble the filament(s) around its surface in the form of a sleeve possesses a discontinuous or irregular surface structure.

All surface irregularities may cover either in part or whole the surface of the rotatable body that receives the filament(s) via the traversing guide or plays some part in the formation and/or build of the yarn sleeve before it is pulled clear.

A preferred embodiment with respect to the rotatable body takes the form of a conical shaped body whose external surface is broken by an echelon structure which may extend either partly or wholly from the apex to the base of the body.

The combination of different godet shapes and surfaces thus provides a virtually infinite diversity of devices suitable for effecting an equal number of different yarn structures.

Particularly useful are those combination which affect yarn structure so as to advantageously influence such properties as air drag factor, bulk factor, denier regularity and yarn pull-off tension, and given below are examples that illustrate the mode of operation of the present invention when employing a modified rotatable body. Air drag factor and bulk factor may be found suitably defined in said patent application Ser. No. 465,080.

These examples are of course in no way intended to limit the scope of the invention described herein.

Example 1 Referring to the accompanying drawing, two filaments 2, of polyhexamethylene adipamide from a spinneret 1 were passed through the filament guide in the sinusoidal traverse mechanism 3 of a peak to peak amplitude of one and a half inches and a frequency of fifty cycles per second and wound onto a conical shaped godet 7. The external surface of the godet was broken to give a ridged steplike or echelon profile which extended at an oblique angle to its axis of rotation from the vicinity of the apex of the cone over approximately a A of its external curved surface area. The godet was positioned two feet below the spinneret face and revolved at a rate of 18,000 rpm. The filaments were wrapped around the godet in the form of a lissajou structure which was made up of two serially connected helices, laid in opposite directions over a length of one and a half inches of the godet surface with one overlapping the other. Each helix was formed during three rotations of the godet so that six turns were laid during the complete traverse cycle. The diameter of the resulting tapered tubular sleeve 4 was 2.5 inches at its widest part and 1.4 inches at its narrowest.

Although the instantaneous winding speed of the godet varied as the filaments traversed the one and a half inches along its length in the direction from the skirt to the nose, it was found that the denier and birefringence of the filaments so traversed was substantially constant at all points along the laid length as shown in the table below.

The results also show that the filaments wound on the godet were adequately oriented.

Under the action of the winding-up means the sleeve was continuously pulled along the longtiudinal axis of the godet, slipped off the nose when it collapsed into an assemblage of loops 5, which was turned inside-out and its direction of movement reversed by withdrawal through the stationary tube 9 located in the passage 6 and hollow shaft 8. The strand of loops was twisted into a yarn 10, in which form it was wound-up into a cheese at a rate of feet per minute.

The stationary tube device is similar to that disclosed and claimed in co-pending cognate patent application Nos. 52,331/ 65 and 52,332/ 65 and functions to advantageously influence the yarn bundle in a similar manner to that indicated in the said co-pending cognate applications. When such a device is used, it is often found desirable, depending upon the shape of the rotatable body, to widen the entrance to the axially-extending passage so as to facilitate the passage of the yarn sleeve from the external surface of the body to the mouth of the tube. Thus, in some instances the apex of the rotatable body may take the form of a lip which protrudes from and encircles the mouth of the stationary tube.

It was observed that the sleeve could be pulled off the godet without assistance of mechanical means other than the wind-up.

The yarn which possessed 11.5 turns per inch had the following properties:

Denier 206 Extensibility percent 30 Yarn pull off tension gms 55 Air drag factor 24.2 Bulk factor 3.5 Denier regularity (percentage mean deviation) perccnt 14 The last property was measured on a Fielden Walker Yarn Irregularity Tester. Individual filaments in the yarn were present as loops which had limbs varying in length up to 18 inches, a birefringence of 0.036 (measured after 24 hours exposure to a normal atmosphere) and a denier of 1.4.

Example 2 Seven filaments of polyethylene terephthalate were fed as described in example one, to a conical shaped godet possessing a symmetrical essentially extended S-shaped profile with a toothed surface similar to that of a rasp file. The teeth projected about mm. above the surface of the godet and there were roughly 28 teeth to every square centimetre of surface. The godet was positioned as in the previous example and revolved at a rate of 15,000 rpm.

The filaments fed to the rotating godet built a similar lissajou structure to that described above and since the overall profile of the godet was similar in dimensions to that used in example one, the dimensions of the resultant tapered tubular sleeve were approximately the same too.

Also as in example one, the denier and birefringence of the traversed filaments remained substantially constant over the laid length, and for a mean godet diameter of 1.9 inches and a mean winding-on speed of 7,450 feet per minute the denier was 0.95 per filament and birefringence 0.117.

Under the action of the winding-up means, the sleeve was pulled from the godet, everted and withdrawn through a stationary tube device. The strand of loops was twisted into a yarn and in this form it was wound-up into a cheese at a rate of 82.5 feet per minute.

Removal of the sleeve from the godet was achieved solely by the wind-up means.

The yarn which possessed 15 turns per inch had the following properties:

Denier 532 Extensibility percent 56 Air drag factor 15.2 Bulk factor 1.38 Tenacity gms. per denier 1.1 Denier regularity (percentage mean deviation) percent 28 The last property was measured as indicated in the previous example.

The use of such modified rotatable bodies and their influence on the resulting yarn was reflected in the attractive, regular and lean appearance and soft warm handle possessed by the yarns.

The yarns, which had the appearance of a twisted cotton yarn possessed good covering power, could be readily dyed and fabrics made therefrom had a pleasant handle. Furthermore, they had excellent bulk and loft characteristics. In terms of structure the yarns comprised an assembly of endless loops of varying lengths twisted together.

Although the examples describe the formation of yarns comprising continuous filaments of circular cross-section, the invention may readily be applied to those of noncircular cross-section and those derived from the slitting of film.

Continuous wholly or partly synthetic filaments which may be used in accordance with this invention include those derived from polyamides (for example, polyhexamethylene adipamide, polyepsilon caprolactam and polyhexamethylene sebacamide and copolymers of these or other polyamides), polyesters (for example, polyethyene terephthalate and polyethylene isophthalate and copolymers of these or other polyesters), polyurethans, arcrylonitrile polymers (for example copolymers of acronitrile, especially with other ethylenically unsaturated monomers such as vinyl chloride, vinyl acetate, methyl acrylate and vinyl pyridine), vinyl polymers generally (for example, polyvinyl acetate, polyvinyl chloride and polystyrene), polymerised fluoroolefins (for example, 'polytetrafiuoroethylene), polymerised hydrocarbons (for example, polyethylene, polypropylene) and halogenated derivatives thereof, viscose rayon, cellulose acetate or similar derivatives of cellulose and proteinaceous polymers.

Composite filaments and physical mixtures or blends of distinct polymer species may also be employed with success.

The yarn produced may be further stretched to increase the molecular orientation of its constituent filament or filaments and consequently the orientation process of the yarn according to this invention may be completed in this Way if the filament or filaments are insufficiently oriented before being wrapped around the rotating body. Further stretching may thus improve the regularity of the yarn with respect to such properties as extensibility, tenacity and denier.

The yarn as passed from the rotating body may be passed through a hot air vortex or steam chamber before being wound up. This ancillary process will cause the material to crystallise and set and thus may improve the stability of the final yarn package. Further, any loops which project beyond the main part of the yarn structure will be caused to adhere to this main part. Such stray loops are a possible source of snagging and breakages when the yarn is used in a subsequent process, or produces fabrics having an undesirable appearance. A1-

ternatively, the loops can be removed by a singeing treatment and this may be applied to either the yarn or to the fabric produced therefrom. Although singeing to improve regularity or appearance can be achieved by numerous techniques such as bringing the yarn or fabric into the vicinity of a red hot wire, it is preferred to contact the material with super heated steam. Singeing by this latter method is particularly suitable if the yarn is to be Warp knitted.

The various post-treatments described above may be performed separately or in combination depending upon the requirements of the particular process, or they may either in part or whole be incorporated into a continuous process so that yarn leaving the godet may be stretched, wet steamed and singed in a continuous operation. If necessary, a spin finish may be applied to the yarn follow ing the final treatment and prior to the winding of a yarn package.

I claim:

1. Apparatus for making a continuous filament yarn which comprises in combination means for extruding a polymeric material into at least one continuous filament, a traverse mechanism arranged to impart a reciprocating movement to the filament, a body having a discontinuous or irregular surface structure and arranged to rotate with a peripheral speed sufiiciently high to apply tension to the filament and to wind the filament around its surface in the form of a sleeve, and means for withdrawing the sleeve from the surface of the body in a direction essentially parallel to its axis of rotation and at a speed less than the peripheral speed of the body so as to insert twist, everting the sleeve simultaneously with, or subsequently to, its withdrawal from the surface, and collecting the yarn that is formed.

2. Apparatus for making a continuous filament yarn as claimed in claim 1 wherein the body contains an axiallyextending passage.

3. Apparatus for making a continuous filament yarn as claimed in claim 1 wherein the surface structure of the body is in part both continuous and discontinuous.

4. Apparatus for making a continuous filament yarn as claimed in claim 1 wherein the body possesses an overall taper from one end to the other.

5. Apparatus for making a continuous filament yarn as claimed in claim 4 wherein the gradient of the taper varies between the ends of the body.

6. Apparatus for making a continuous filament yarn which comprises means for extruding a polymeric material into at least one continuous filament, a traverse mechanism arranged to impart a reciprocating movement to the filament, a body having a discontinuous or irregular surface structure and containing an axially-extending passage, said body being arranged to rotate with a peripheral speed sufiiciently high to apply tension to the filament and to wind the filament around its surface in the form of a sleeve, and means for Withdrawing the sleeve from the surface of the body at a slower speed than the peripheral speed thereof, pulling the withdrawn sleeve through the passage in the body thereby everting the sleeve and collecting the yarn that is formed.

References Cited UNITED STATES PATENTS 3,388,545 6/1968 Cannon et a1. 57--l40 JOHN PETRAKES, Primary Examiner U.S. Cl. X.R. 57-34, 157.

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