SEWING THREAD AND ITS MANUFACTURE
A method of manufacturing textured thread textured thread comprises the steps of: processing textured yarn having a zero or near-zero twist by applying a singles twist thereto; plying at least two textured yarns together by twisting them in a direction opposing the singles twist; wherein the singles twists lie in the range 4 to 20 turns per inch and the plying twist lies in the range 2 to 18 turns per inch.
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1. Field of the Invention
The present invention relates to sewing thread and its manufacture and, more particularly, to the manufacture of what is known as “textured thread”.
2. Description of Related Art
One of the basic elements of manufacture of sewing thread is what is referred to in the art as “yarn”. A simple yarn is produced by combining single fibres or filaments. One way of combining fibres is by applying a twist to them, known as a singling twist (since there is but a single group of fibres that are being twisted together). The application of a twist to filaments to produce a yarn is not essential, however, and fibres may also be combined without doing so. The characteristics of the fibres which are combined to form the yarn play a significant role in the eventual characteristic of a sewing thread for whose manufacture, ultimately, such yarns are used; as do the characteristics of the yarns themselves.
Yarns can be manufactured from a variety of fibres, such as staple fibres which are lengths of fibre; and continuous filaments which are typically made of artificial material by processes such as melt-spinning. Threads are created by ‘plying’ together two or more yarns by twisting the yarns around each other.
One particular kind of thread is known as “textured thread”. This is produced from yarn which has had a ‘texture’ applied to it subsequent to the individual filaments being combined with each other. Texturing can be achieved by, for example, directing an air jet at the yarn shortly after the filaments produced by melt-spinning exit the melt-spinning apparatus (i.e. when it is still soft and susceptible to disruption) or by what is known as “false twisting”. False twisting is a process in which the combined filaments are first twisted and set in that condition by heat (typically steam heat), following which they are then once again untwisted. False twisted yarn has no twist, but a ‘memory’ in the filaments which make up the yarn, introduced by the heating process, nonetheless causes them to behave as if they were twisted. Textured yarn and thread manufactured from textured yarn therefore both have, as a result of this characteristic, a relatively soft ‘handle’ (i.e. feeling to touch) relatively high bulk (i.e. low density) and high elongation (i.e. longitudinal elasticity under tension). Textured thread therefore tends to be of use in certain areas of garments where soft seams are required. It has the advantage of being inexpensive to manufacture primarily because relatively inexpensive raw materials are used. However, its characteristics make it a difficult thread to work with because of its susceptibility to cause sewing faults such as snagging, looping and breaking during sewing operations. Further, it has relatively low strength. Accordingly, textured thread is unsuitable for wider applications, such as apparel stitching (i.e. stitching of panels of fabric to construct garments).
SUMMARY OF THE INVENTIONA first aspect of the present invention lies in an appreciation of the ability to employ textured thread more widely in circumstances where the above-mentioned problems can be overcome. According to a first embodiment of the present invention, textured thread is manufactured by plying yarns having a zero or near-zero twist, the twist imparted to the plied yarns being substantively greater than that previously thought to be acceptable in a textured thread.
A further aspect of the present invention provides a method of producing a textured thread. Yet a further independent aspect of the present invention provides a method of apparel stitching using textured thread having the characteristics of an embodiment of textured thread according to the present invention.
Embodiments of the present invention will now be described, by of example, and with reference to the accompanying drawings in which:
Referring now to
Referring now to
The continuous filament yarn whose manufacture has thus far been described is also known as a flat filament yarn, mimicking to some degree the characteristics of silk filaments and is entirely conventional.
Referring now to
As mentioned previously, it is known to produce “textured” yarn which, in turn, may then be used to manufacture ‘textured’ sewing thread. One way in which textured yarn is manufactured is by imparting high pressure air to the yarn formed of continuous filaments. The air serves to disrupt the regularity of the yarn before it has entirely cooled, thereby to impart the requisite “texture” to it. Another manner of providing a texture is to impart what is known as a false twist. The continuous filament yarn is first twisted and then is set into that condition by steam heat; thereafter, it is once again untwisted. The result is that the final twist in the yarn is zero but the filaments of the yarn have a memory of their original, twisted configuration (hence the term ‘false’ twist). This false twist causes the individual filaments within the yarn to tend to twist, loop and snarl within its body thereby resulting in a relatively soft and bulky yarn having the requisite textured properties. Referring once again to
Traditionally, thread manufactured of textured yarn, although having desirable properties of high bulk and high levels of elongation (that is to say elastic longitudinal expansion under tension) and a soft handle, has proved to be unsuitable for the majority of uses such as apparel sewing (that is to say the joining of fabric panels as part of a manufacture of a garment). Typically, reasons for this include low relative strength of such thread, together with a tendency to cause sewing defects such as breaking during sewing, snagging within the machine, skipping a stitch or the bobbin chase failing to catch the thread properly.
The inventors of the present invention have observed that the limitations on the use of textured threads arise, inter alia, from the characteristic of limited cohesion between individual filaments of the textured yarn from which the thread is made. Such limited cohesion allows the fibres of the yarn to open up and/or separate from each other during sewing. This, in turn, can result in broken filaments and may even result in total failure of the thread as a whole. The inventors have realised that it is possible to apply twist levels to textured yarn which are greater than those in the prior art and therefore serve to avoid the problems which arise from low fibre cohesion; yet, at the same time, maintain a sufficiently low degree of twist within the yarn to enable yarns to be plied together at a sufficiently low counter-torque (i.e. acting antagonistically to the torque applied by the twist in the individual yarns) that the resultant thread retains the desirable characteristics of textured thread. Further, the inventors have appreciated that, in processing the yarns to make this new textured thread, the tensions which are applied are preferably sufficiently low to avoid elongating the yarns to such an extent that the resultant, plied thread takes on more of the characteristics of traditional, flat filament yarn which lacks the bulk and soft handle of textured thread. This ‘squaring of the circle’, previously considered to be impossible, results in textured thread which is suitable for needle sewing and therefore can be used for apparel stitching, where previously this was not thought to be possible.
Referring now to
Alternatively, for heavier thread sizes, two separate steps are typically performed. Thus, the stretch and twist step 512 is then followed at step 516 by winding of the twisted singles yarn onto a spool (usually known as a ‘pirn’). Thereafter, the two or more singles yarns are then plied together at step 518 on a separate machine. In either case, both plying steps 514 or 518 are followed by a further winding step 520 of the resultant griege thread. The griege thread is then dyed at step 522 in the conventional manner used for other polyester yarns, that is to say autoclaving for natural white thread, and conventional package dyeing for other colours. The dyed thread has lubricant applied to it in the conventional manner and is lubricated and finish wound onto a user package at step 524.
Referring now to
The twist imparted to the yarn at step 512 is lower than that which is typically applied to continuous, flat filament yarn. It has been found that applying such levels of twist causes the resultant thread to exhibit very few, if any textured characteristics, or to a very small degree. Accordingly, the levels of twist applied are greater, than those applied in conventional textured thread manufacture but lower than those applied when creating thread from continuous, flat filament yarn.
Conventionally, textured thread is manufactured by plying several textured filament yarns together. Typically, the yarns are given very low amounts of twist; typically in the region of ½ to 1 turn per inch; the degree of twist imparted upon plying multiple yarns together to create thread is necessarily related to that twist level (in order for the plied thread to have a neutral overall torque, or at least a stable construction) and so is correspondingly low. Conventional wisdom has consistently held that it is not possible to impart any greater levels of twist to create textured thread for a variety of reasons, amongst which is the belief that doing so causes the thread manufactured from textured filament yarn to lose the very characteristics for which it is used in the first place.
According to an embodiment of the present invention, textured continuous filament yarn is spun into a sewing thread which is then capable of being used for apparel stitching and other, similar uses previously thought improper in textured thread. An embodiment of the present invention produces a textured thread suitable for sewing is manufactured by a method which comprises the steps of: creating a continuous filament yarn having a false twist thereby imparting texture to the yarn; imparting a further twist in the range of between 5.5 and 18.7 turns per inch to the false twisted continuous filament yarn, the twist being in a first rotational direction; generating a thread by plying two or more textured continuous filament yarns with each other in a second rotational direction, and having a twist within the range 3.9 to 17 turns per inch.
Details of specific values and ranges of twisting and plying combinations for different thread weights (expressed both in terms of denier, tex and decitex parameters) are illustrated in this table both in turns per inch (TPI) and turns per metre (TPM) in
Referring now additionally to
Textured thread created in this way has a number of advantages. Textured filament yarn is relatively inexpensive as a raw material and its manufactured into textured thread requires relatively fewer manufacturing steps than would be the case for a thread which would be required to perform equivalent functions, such as a corespun thread. Further because lower levels of twist are imparted than for thread made of conventional, flat filament continuous yarn, the thread has a lower profile when used for apparel stitching (which, of course, textured yarn was never previously suitable for). The relatively higher levels of elongation of the resultant thread when compared with conventional continuous flat filament thread is also an advantage when used for the seams of active wear garments, which frequently require a higher stretch due to the character of the fabric employed.
Claims
1. A method of manufacturing textured thread textured thread comprising the steps of:
- processing textured yarn having a zero or near-zero twist by applying a singles twist thereto;
- plying at least two textured yarns together by twisting them in a direction opposing the singles twist;
- wherein the singles twists lie in the range 4 to 20 turns per inch and the plying twist lies in the range 2 to 18 turns per inch.
2. A method according to claim 1 wherein the textured yarn is produced with a false twist.
3. A method according to claim 1 wherein the textured yarn is produced by the application of pressured air.
4. A method according to claim 1 wherein the textured yarn is processed at a speed which is lower than for standard continuous filament thread of the same weight.
5. A method according to claim 4 wherein, for thread weights of between 18 and 120 Tex, the textured yarn is processed at between 82 and 95% of the speed at which continuous filament yarns of the same weight are processed.
6. A method according to claim 4 wherein the textured yarn is processed at a tension which is lower than for standard continuous filament yarns of the same weight.
7. A method according to claim 6 wherein, for thread weights of between 18 and 70 Tex, the plying step takes place at a tension of between 65% and 40% of the tension for continuous filament thread of the same weight.
8. A textured thread comprising a plurality of textured yarns plied together, wherein each textured yarn has a twist of 4 to 20 turns per inch and the textured yarns are plied together with an opposing twist of 2 to 18 turns per inch.
9. A textured thread according to claim 8 wherein the textured yarns have a false twist.
10. A textured thread according to claim 8 wherein the textured yarns were created by the application of pressured air.
11. A method of manufacturing apparel comprising the steps of stitching two panels of fabric together using a textured thread comprising a plurality of textured yarns plied together, wherein each textured yarn has a twist of 4 to 20 turns per inch and the textured yarns are plied together with an opposing twist of 2 to 18 turns per inch.
12. A garment comprising a plurality of panels of fabric, at least two of which are stitched together by a textured thread comprising a plurality of textured yarns plied together, wherein each textured yarn has a twist of 4 to 20 turns per inch and the textured yarns are plied together with an opposing twist of 2 to 18 turns per inch.
Type: Application
Filed: Oct 7, 2011
Publication Date: Nov 7, 2013
Applicant: COATS PLC (Middlesex)
Inventors: William C. Stuckey (Hendersonville, NC), Bernhard Kobsa (Tepepan)
Application Number: 13/878,102
International Classification: D02G 3/28 (20060101); D02J 1/08 (20060101); A41D 31/00 (20060101); D02G 1/02 (20060101);