US3496715A

US3496715A - Filament and method of forming same

Info

Publication number: US3496715A
Application number: US707736A
Authority: US
Inventors: Joseph Fitton
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-02-23
Filing date: 1968-02-23
Publication date: 1970-02-24
Anticipated expiration: 1987-02-24

Description

Feb. 24, 1970 J. FITTON 3,496,715

FILAMENT AND METHOD OF FORMING SAME Filed Feb. 25. 1968 fhluiapl Wi d/Lu- United States Patent 3,496,715 FILAMENT AND METHOD OF FORMING SAME Joseph Fitton, Great Howarth House, Wardle Road, Rochdale, Lancaster, England Filed Feb. 23, 1968, Ser. No. 707,736 Int. Cl. D02g 3/02, 1/00; D01d 5/22 US. Cl. 57140 13 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates to filaments in general, and more particularly to the treatment of filaments. Still more specifically, the present invention relates to a met-hod 'of treating filamentary material, and to a novel filamentary material obtained in accordance with this method.

It is well known to crimp filaments and filamentary materials, which latter term designates yarns and similar multi-filament structures. The term filament will hereafter be employed to designate in its broadest aspect all conceivable interpretations, that is multi-filaments, monofilaments and the like.

Once having been crimped, a filament has a given crimp modulus which term is intended to be an indication of the ability of a crimped filament to recover its crimped configuration upon being stretched and released, and this term is related to the crimp rigidity of the filament. Crimp rigidity is measured by extending the filament under a load sufiicient to straighten the filaments or filament so that the crimp is removed, and thereupon allowing the filament to contract under a very much smaller load. The crimp rigidity is considered to be the amount of contraction expressed as a percentage of the fully extended length. In general terms, a yarn or filament having a high crimp modulus also has a high crimp rigidity. It will be readily understood that for many applications thehighest obtainable crimp rigidity, and therefore the highest obtainable crimp modulus, is desirable.

For this reason industry has long sought to devise a means for increasing the crimp modulus of a crimped yarn. This, however, heretofore has encountered difiiculties.

SUMMARY OF THE INVENTION The present invention overcomes these difiiculties.

More particularly, the present invention provides a method of increasing the crimp modulus of a filament.

Still more particularly, the present invention provides a method by which a crimped filament or crimped yarn having a given crimp modulus is processed to produce a crimped filament or crimped yarn having a higher crimp modulus.

The method in accordance with the present invention is relatively simple and requires for its carrying out no substantial technological expenditures, thus adding little if anything to the expense of making the filament or yarn.

In accordance with one feature of the invention I pro- Ice vide a method of increasing the crimp modulus of a filament, which method includes the steps of advancing an elongated filament of given cross section in a predetermined path, and crimping the filament to thereby obtain a plurality of longitudinally arrayed curved filament portions each of which transversely extends of the longitudinal extension of the filament. Thereupon, the filament portions are subjected to deformation of a magnitude requisite for obtaining at all points of each of the filament portions a cross sectional configuration whose major dimension is located in the plane of curvature of the respective filament portion. In other words, the filament is substantially flattened along its longitudinal extension, but in such a way that the major dimension of the resulting cross-sectional configuration is located in the general plane of curvature of each curved filament portion, that is each crimped portion of the filament. It is this increased cross-sectional dimension in the plane of curvature of the crimp to which in accordance with the present invention the higher crimp modulus of filaments treated according to the present method is attributable, because this increases the resistance to and facilitates the recovery from straightening of the filament under load.

The crimp in the yarn or filament may be latent crimp and may be developed, for instance by heating, before the filament or yarn is subjected to such deformation.

The deformation itself may be carried out by suitable pressure-applying means, such as pressure rollers which are in line contact with one another and between which the filament or yarn passes, While pressure is being applied the yarn may be heated, and such heating may occur upstream of the application of pressure or it may occur simultaneously with application of pressure, for instance by heating of the pressure-applying means. I have found it advantageous, in cases where a multi-filament structure such as a yarn is to be treated in accordance with my method, to mechanically or electrostatically spread the individual filaments of the structure in sheetlike fashion transversely of the direction of movement of the structure prior to entry of these filaments into the pressure-applying means.

It is clear that my method may be carried out continuously, and that the crimp can be applied in a suitable manner-if it is not already present as a latent crimpsuch as by twist crimping or false twist crimping.

My invention also relates to a novel yarn produced in accordance with the aforementioned method.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic illustration showing apparatus suitable for carrying out the method according to the present invention; and

FIG. 2 is a highly magnified stylized perspective view of a portion of a filament which has been treated in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail it will be seen that FIG. 1 shows a filamentary structure, which here is assumed to be a multi-filament yarn 10; which is advanced in the direction toward the left-hand side of the drawing by means of a pair of feed rollers 11 which rotate in the direction indicated by the arrows associated therewith. Arranged downstream of the rollers 11 is pressure-applying means which here is illustrated as a pair of coacting pressure applying rollers 12. The rollers 11 rotate at a peripheral speed which is greater than that of the rollers 12, which latter also rotate in the direction of the curved arrows which are associated with them, whereas the straight arrows indicate the direction in. which they apply pressure towards one another. Rotating of the rollers 11 at a peripheral speed in excess of that of the rollers 12 results in an overfeed of the yarn between the two sets of

rollers

11 and 12. a i 7 A heater 14 of suitable construction well known in the art is arranged between the

rollers

11 and 12 and in the illustrated embodiment serves to encourage development of the crimp in the yarn 10, which in this instance is assumed to possess a latent crimp; Of course, the yarn can aiso be twist crimped or false-twist erimped if it does not have latent crimp character'istics. How the crimp comes about is of no consequence in accordance with the present invention; the important point is that the yarn be crimped prior to entering between the rollers 12.

Crimping of the yarn in whatever selected fashion of course results in the production of a plurality of longitudinally arrayed curved filament portions, that is a plurality of filament portions on each of the filaments, with each of these portions beirig curved and extending transversely of the longitudinal extension of the respective filament. It is of course well knowri that the. crimps in the individual filaments of a yarn such as the multi-filament yarn 16 illustrated in FIG. 1 will have their planes of curvature disposed in substantially random manner. This is particularly true in the case of latent crimp which develops into an actual crimped state; on being encour= aged by heating with the heater 14. 7

As the yarn 10 enters the nip of the pressure applying rollers 12 of the embodiment illustrated in FIG. 1 the individualfilaments' of the yarn will twist so that the pianes of curvature of substantially all of the crimpsof each of the filaments become aligned with the line of contact between the pressure rollers. It is in this condition that each of the crimped filament portions passes through the nip between the presstire rollers 12. In so doing the cross section of each of the filaments is varied. In other words, the cross section of each of the filaments is flattened with the result that downstream of the rollers 12 the major dimension of the cross-sectional configuration of each filament will lie in the plane of curvature of the crimped portion at any point along the filament. This is illustrated by way of an example in FIG: 2 which, however, is a highly stylized showing not intended to be representative of the actual configuration, but only suggestive thereof. FIG. 2 shows a short length of filament treated in accordance with the present invention and it will be seen that the cross section there is shown to be substantially rectangular. It will, of course, be realized that the actual cross section of filament treated in accordance with the present invention will not be precisely of this shape, but will be rather more of an elliptical section which may have slightly flattened sides. FIG. 2 does, however, serve to suggest that the major dimension of the filament cross section extends, once the filament has been treated in accordance with the present invention, in the plane of curvature of the respective crimped portion, that is the plane of curvature of each crimp.

Also in accordance with the present invention I have found it advantageous if the individual filaments of a multi-filament yarn such as that shown in FIG. 1 are spread transversely of the direction of yarn advancement in sheet-like fashion before they pass into the nip between the pressure rollers 12 or whatever other pressureapplying means is being utilized. This will facilitate realignment of the individual filaments so that the planes of curvature of substantially all the crimps become aligned with the line of contact between the pressure rollers, as pointed out before. Such spreading can be effected either mechanically or electrostatically in a manner which is well known in the art and need not therefore be described fiirther in detail.

on being processed in accordance with the present invention, the yarn 10' is then taken up on a conventional take-up 15, as illustrated in FIG. 1. i

By treating a yarn in accordance with my novel method so that the greatest cross-sectional dimension of each filament of the yarn at any point along the respective filament will lie in the plane of curvature of the respective crimped portions of each filament, the crimp resistance to straightening of the individual filaments is considerably increased, and hence the crimp modulus of the yarn is also increased. It is clear that this represents a significant advance in this field and provides the type of special filament, or special yarn, which has long been sought in this industry but which heretofore has .not beenavailable.

Yarn made from filaments treated in accordance with my present invention, and fabric made from such yarn, should not only have particularly good recovery characteristics from extension, but can also be expected to exhibit excellent flexibility and draping characteristics as well as superior cover and opacity.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of filamentary structures differing from the types described above;

While the invention has been illustrated and described as embodied in a method for increasing the crimp modulus of a crimped filament, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.

What is claimed as new and desired tobe protected by Letters Patent is set forth in the appended claims:

1. A method of processing a filament, comprising the steps of advancing in a predetermined path an elongated filament having a given cross-section and composed of a plurality of longitudinally arrayed curved filament portions each of which extends transversely of the longitudinai extension of said filament; and subjecting said filament portions to deformation requisite for obtaining at all points of each of said filament portions a cross-sectional configuration having its major dimension in the plane of curvature of the respective filament portion.

2. A method as defined in claim 1, wherein the step of subjecting said filament to deformation comprises engaging and subjecting each filament portion to pressure from opposite sides of the plane of curvature of the respective portion.

3. A method as defined in claim 1, wherein the step of subjecting said filament to deformation comprises arranging two pressure-applying surfaces transversely of said path in line contact with one another, aligning the plane of curvature of each filament portion with the line of contact between said surfaces, and advancing each filament between said surfaces.

4. A method as defined in claim 1; and further comprising the step of heating each filament portion while subjecting the same to said deformation.

5. A method as defined in claim 1; and further comprising the initial step of crimping said filament preliminary to said step of subjecting the filament to deformation, to thereby obtain said curved filament portions.

6. A method as defined in claim 1, wherein said filament is possessed of latent crimp; and wherein the step of crimping said filament comprises developing the latent crimp of said filament prior to deformation of said filament portions.

7. A method as defined in claim 6, wherein the step of developing the latent crimp in said filament comprises heating said filament.

8. A method as defined in claim 6, wherein the step of developing the latent crimp of said filament comprises overfeeding said filament so as to permit the latent crimp thereof to develop.

9. A method as defined in claim 1, wherein the step of crimping said filament comprises false-twist crimping said filament.

10. A method as defined in claim 1, wherein all of said steps are performed continuously.

11. A method as defined in claim 1; and further comprising the steps of advancing additional similar filaments in said predetermined path simultaneously with the firstmentioned filament; orienting the filament portions of all of said filaments on entry of each portion into a predetermined increment of said path so that the plane of curvature of each curved filament portion at least temporarily coincides with a given plane; and subjecting all of said filament portions to said deformation while their respective planes of curvature coincide with said given plane.

12. A method as defined in claim 11; and further comprising the step of spreading said filaments transversely of their direction of advancement in said path prior to subjecting said filament portions to said deformation.

13. As a novel article of manufacture, a yarn comprising a plurality of elongated crimped filaments each of which includes a plurality of longitudinally arrayed curved filament portions extending transversely of the longitudinal extension of the respective filament, each of said filament portions having its major cross-sectional dimension in the plane of curvature of the respective filament portion.

References Cited UNITED STATES PATENTS 2,601,771 7/1952 Cameron.

3,065,519 11/1962 Starkie.

3,162,995 12/1964 Comer et a1. 57-140 XR 3,196,602 7/1965 Jenkins et al. 57-34 XR 3,332,226 7/ 1967 Rosenstein 57-140 3,358,345 12/1967 Daniel 28-12 3,404,522 10/ 1968 Stoll et a1. 57-34 3,412,192 11/1968 Clapson 28-12 XR 3,421,193 1/1969 Taylor 28-7215 DONALD E. WATKINS, Primary Examiner US. Cl. X.R.