WO2003060211A1

WO2003060211A1 - Covered yarn and method for production thereof

Info

Publication number: WO2003060211A1
Application number: PCT/EP2003/000392
Authority: WO
Inventors: Thomas Vogelsaenger; Steffen MÜLLER-PROBANDT
Original assignee: Temco Textilmaschinenkomponenten Gmbh
Priority date: 2002-01-18
Filing date: 2003-01-16
Publication date: 2003-07-24
Also published as: KR20040079938A; AU2003235634A1; CN1620531A; EP1478795A1; DE10202008A1

Abstract

The invention relates to a covered yarn made from a highly elastic thread and a face yarn wound around the above. On extending the prepared covered yarn the wound thread is stretched and remains untwisted as the elastic thread is wound around the stretched wound thread. Production of the covered yarn is achieved by winding around the highly elastic thread on pre-tensioning the highly elastic thread to a greater degree than the tension in the winding thread on winding. The winding thread is thus turned on winding around the elastic thread, which, on extending the prepared covered yarn, is released such that the wound thread, when the applied stretch of the article made from the prepared covered yarn is reached, remains essentially untwisted and the filaments thereof lie essentially parallel to each other.

Description

WINDING YARN AND METHOD FOR THE PRODUCTION THEREOF

The invention relates to a wrapping yarn which consists of a highly elastic thread and a cover thread wrapping around it, and a method for its production.

Wrapping yarns of this type have a highly elastic thread as the core thread, be it as a monofilament or multifilament, which is covered with a cover thread to protect the highly elastic core thread. While the highly elastic core thread causes the elasticity and the stretch of the wrapping yarn, the cover thread should give the wrapping yarn a desired textile appearance in order to give the end product the appropriate properties and feel. Wrapping yarns of this type are used, for example, for the production of women's stockings and tights.

These items require a good fit and fit on the body or leg so that the stocking is worn in a stretched state. This stretch can be between 200 and 500%. The problem now arises that the strong elongation results in a shift in the position of the core thread and the wrapping thread, so that despite tight wrapping the core thread is sometimes bare without protection. In this state, the core thread can be easily damaged. In addition, the stocking has a bad appearance because the core thread comes to the surface. It is therefore endeavored to apply as many turns as possible to the core thread for a highly qualified thread.

In the conventional winding of an elastic thread, the winding thread is applied to a hollow spindle and rotates with it. To increase Productivity demands higher and higher take-off speeds and thus higher spindle speeds. There is therefore a limit to the size of the spools, because on the one hand longest possible run-off times are to be achieved, on the other hand spools with a weight of 10 kg, for example, not with a spindle speed of 40,000 revolutions / min. can circulate. It has therefore already been proposed to arrange both the cover thread spool and the core thread spool in a stationary manner, the cover thread being looped around the core thread spool and being driven by a disk or a wing for the purpose of being wound (US Pat. No. 2,737,773, DE 4 101 329). The balloon that forms envelops the stationary core thread spool. However, the achievable achievements are not yet satisfactory, so that the wrapping yarn is relatively expensive to manufacture.

The object of the invention is to provide a wrapping yarn which is cheaper to produce and yet has good covering properties.

This object is achieved by the features of the product and the process claim.

The invention is based on the knowledge that, surprisingly, good covering power and coverage of the core thread takes place if the filaments of the winding thread come to lie parallel to one another and are opened with increasing elongation of the finished winding thread, while the highly elastic core thread wraps around the winding thread in a very steep spiral , As a result, the stretched wrapping thread is only slightly looped through the core thread in the stretched state. The open filaments of the stretched wrapping thread are not constricted by this wrapping, so that the wrapping thread can develop very good covering power even when stretched. During production, care must be taken to ensure that the core thread is wound with such an elongation (pretension) that the stretching thread is largely free of rotation when it is in use, so that the filaments essentially lie next to one another, and the core thread attaches to the winding thread wraps around this stretching state in a steep spiral.

It has also proven to be particularly advantageous for the highly elastic core thread to be fed without rotation and for the winding thread to meet the elastic core thread substantially perpendicularly at the winding point. This results in a particularly even and exact winding. In order to obtain an absolutely rotation-free winding thread when stretching, it can be expedient to compensate for the rotation imparted to the winding thread by a counter-rotation by the bobbin take-off or when the winding thread bobbin is rotating. It is also expedient if the wrapping takes place with a pretension of the core thread of approximately 2/3 of the elongation in use of the finished wrapping yarn.

Further details of the invention are described with reference to the figures.

Show it:

Fig. 1: A winding according to the prior art with a parallel structure of the winding thread when winding.

Flg. 2: The wrapping yarn according to FIG. 1 in a stretched state.

Fig.3: A wrapping yarn according to the invention and its structure in see- matic representation in a relaxed state.

Fig. 4: The wrapping yarn according to the invention of Fig. 3, but in a stretched state.

Flg. 5: Microfoto yarn structure - relaxed.

Fig. 6: Gran structure microphotograph - stretched.

Flg.7: A device for producing the wrapping yarn according to the invention.

Wrapping yarns 10 are usually produced in such a way that the wrapping thread 1 is wound around the elastic core thread 2. Such a structure is shown in FIG. 1, in which the wrapping thread 1 is wound around the core thread 2 in a parallel structure. To compensate for the moment that arises, the elastic thread 2 can also be given a rotation before the winding thread is wound around it (US 2,737,773, US 4,509,320). When this wrapping yarn structure is stretched, the wrapping thread 1, which is in itself rotationless, receives twists (FIG. 2) by pulling the wrapping loops apart, as a result of which the wrapping thread 2 is combined and compressed and loses volume, such a production method is described, for example, in US Pat. No. 4,509,320. The individual filaments 11, which were still lying parallel next to each other during the winding, are turned around one another when stretched. The winding thread 1 closes the more the unwinder yarn 10 is stretched, so that the core thread 2 loses its embedding in the winding thread 1. The result of this is that the opacity of the winding thread 1 decreases considerably as a result of the lower volume. Significantly more turns are required to be able to do this even when stretched Use of the article made from the wrapping yarn 10 takes place to achieve good opacity and thus a satisfactory grip and appearance. Therefore, at least 1200-1700 turns / meter are usually provided for a quality yarn.

Figure 3 shows a yarn structure according to the invention in a schematic representation in the relaxed state. The winding thread winding around the core thread 2

I loosely loops around the core thread 2 in tight turns and has a twist in the opposite direction to the winding. That in the relaxed state, the winding thread 1 is combined by this counter-rotation, so that the individual filaments 11 appear bundled. If, on the other hand, this wrapping yarn 12 is stretched, as is used in the article, then the counter-rotation is canceled, the wrapping thread 1 opens, the filaments

I I lie approximately parallel to one another, so that the yarn structure of the stretched wound yarn 12 appears more voluminous (FIG. 4). With increasing elongation of the finished wrapping yarn 12, the opened filaments 11 are successively stretched and come to lie parallel to one another. They are open, while the elastic core thread 2 wraps around the winding thread 1 in a very steep spiral.

The astonishing and surprising thing here is that this more parallel position of the filaments 11 of the wrapping thread 1 results in a substantially better covering power and also a better grip than if the winding thread 1 wraps around the core thread 2 more frequently and in the stretched state the wraps around the core thread 2 Filaments 11 are twisted together and constricted by the core thread. The fact that the winding thread 1 is open also results in a softer grip than if the winding thread 1 receives rotation when stretched and the filaments 11 are thus bundled. FIGS. 5 and 6 show the yarn structure according to the invention as a microphotograph in the relaxed and in the stretched condition. In the relaxed state (FIG. 5), the core thread 2 lies in the stretched state in the winding thread 12, while the winding thread 1 loops around this core thread 2 in a spiral. The filaments 11 of the winding thread 1 are slightly twisted around each other. The more the wrapping thread is stretched, the more the twisting of the wrapping thread 1 dissolves.

The wrapping yarn 12 is shown in FIG. 6 in the stretched use stretch. It is clearly visible how the filaments 11 of the wrapping thread 1 are stretched and approximately parallel to one another and how the core thread 2 wraps around them in a steep spiral.

The better covering ability of the open winding thread 1 has the result that the same covering effect can be achieved with significantly fewer turns. While typically 1200-1700 turns / meter were required for a quality yarn, in a yarn structure according to the invention, at most 80% of the usual turns or less is sufficient to achieve the same covering effect. Investigations were carried out and tests were carried out which allowed the windings to be lowered to 750 / meter without the quality of the opacity being impaired. The handle of such a yarn in the end product is better. Apparently, this surprising effect is also due to the fact that the wrap angle is steeper due to the smaller number of turns / meter and thus the winding thread 1 is less constricted by the elastic core thread 2 in the stretched state.

Lowering the wraps to 80% and even to 50% means a considerable reduction in production costs, which is why these yarns can be produced with a cost saving of at least 30%. The wrapping yarn according to the invention is expediently produced in such a way that the elastic core thread 2 is fed from a stationary bobbin 6 under such a stretch that the wrapping thread 1 is essentially stretched and free of rotation when the article produced from the wrapping yarn 12 is stretched for use (Fig. 7). If a winding device is used in which the winding thread bobbin rotates, the winding thread 1 receives a rotation by this rotation, which is not resolved by the stretching and prevents the winding thread from opening in the stretched state. In this case, it is necessary to give the winding thread 1 an opposite twist in the amount of the number of wraps, which is reversed again by the wrapping.

If the winding thread is fed from a stationary winding thread spool, it is not necessary to give the winding thread a counter-rotation. The rotation caused by the thread being pulled off the bobbin is negligible. It has proven to be expedient for an exact winding that the winding thread 1 is fed essentially at the winding point 7 perpendicular to the thread path of the elastic thread 2. The core thread 2 does not receive a pre-twist, but is fed without rotation. It is immaterial whether the coils 6, 21 are unwound overhead or circumferentially.

FIG. 7 shows, for example, a device with which the wrapping yarn according to the invention can be produced. The winding thread 1 is drawn off overhead from a fixed bobbin 21 and guided through the inside of the bobbin 21 via a thread brake 14. Through the thread guide 22 of the bobbin holder 23, the wrapping thread 1 leaves the axis of the bobbin 21 and is fed to a wrapping wing 9, which is fastened on the spindle 8 and is driven by it. An opening is located in the spindle 8 just below the winding wing 9. voltage provided, through which the winding thread 1 strikes the core thread 2 in an approximately radial direction and winds around it by the rotation of the winding wing 9. The core thread 2 is likewise drawn off from a bobbin 6 which is arranged coaxially with the winding thread bobbin 21 and is mounted on a bobbin holder 61 which is arranged in a rotationally fixed manner with respect to the spindle 8. The core thread 2 passes through a thread brake 14, which is used to set the desired core thread tension or its extension, through the axis of the bobbin 6 to the winding point 7, where the core thread 2 is combined with the winding thread 1. The wrapping yarn 12 consisting of wrapping thread 1 and core thread 2 is fed by means of a thread take-off 4 through the hollow axis of the spindle 8 via a traverse 51 to the winding 5.

With regard to the stretching of the core thread 2 during the wrapping, it is important to pay attention to the later use stretch with which the wrapping yarn 12 is to be used. It has been found through experience that the winding stretch of the core yarn 2 must be less than the working stretch in order to achieve the structure according to the invention in the winding yarn 12 in the article. In various applications, e.g. B. in the manufacture of stockings and tights, it has been found that a stretching of around 200% is expedient for an elongation in use of 300%. Depending on the intended use of the end product, the exact parameters can be determined experimentally. What is important here, however, is the knowledge that there is a connection between the stretching of the wrapping and the stretching in use and thus the volume can be significantly influenced.

Claims

Patent claims

1. Wrapping yarn, which consists of a highly elastic thread and a winding thread, characterized in that at one

Elongation of the finished wrapping yarn (12; 13), the wrapping thread (l) is stretched and free of twist and the elastic thread (2) wraps around the ^» stretched wrapping thread (1).

2. Wrapping yarn according to claim 1, characterized in that the wrapping thread (1) is a multifilament thread and the individual filaments (11) lie substantially parallel to one another in the stretched state during use, while the elastic core thread (2) wraps them in a steep spiral ,

3. Yarn according to one of claims 1 or 2, characterized in that the wrapping yarn (12) has at least 20% less wrapping than normal in the relaxed state.

4. Yarn according to claim 3, characterized in that the wrapping yarn (12; 13) has about 600 to 850 wraps / meter in the production stretch.

5. Yarn according to one or more of claims 1 to 4, characterized in that the core thread (2) is wound by a plurality of winding threads (1; 3).

6. Method for producing a wrapping yarn, which consists of a highly elastic thread and a thread wrapping around it, wherein the wrapping takes place with a pretension of the highly elastic thread which is greater than the tension of the wrapping thread during the wrapping, characterized in that the wrapping thread (1; 3) receives a rotation when the finished wrapping yarn (12; 13) is wound, which dissolves again when stretched and that the wrapping thread (1) is largely free of rotation when the article produced from the wrapping yarn (12) expands and its filaments (11; 33) lie essentially parallel to one another.

7. The method according to claim 6, characterized in that the wrapping thread (1) is fed substantially at the wrapping point (7) perpendicular to the thread path of the elastic core thread (2).

8. The method according to any one of claims 6 or 7, characterized in that the wrapping thread (1; 3) is fed from a stationary bobbin and receives a twist when winding the elastic core thread (2), which occurs when the finished wrapping yarn (12 ; 13) dissolves again.

9. The method according to one or more of claims 6 to 8, characterized in that the highly elastic core thread (2) is fed without rotation.

10. The method according to one or more of claims 6 to 7 and 9, characterized by the fact that on the winding thread (1; 3) before the winding a counter-rotation is applied in the amount of the intended winding, which is after the winding when stretching (stretching ) of the finished thread (12; 13) dissolves again, and the thread (1; 3) is fed from a rotating bobbin.

11. The method according to claim 10, characterized in that the winding thread (1; 3) for the winding with counter-rotation is presented.

12. The method according to one or more of claims 6 to 11, characterized in that the core thread (2) is wound with the thread (1; 3) under a pretension of about 2/3 of the elongation in use of the winding thread (12; 13).

13. The method according to claim 12, characterized in that the pre-winding of the core thread (2) is about 200% for an elongation of use of about 300%.

14. Wrapping yarn according to one or more of the preceding claims, characterized in that the yarn is elastic and is used for the production of stockings and / or tights (hosiery).