FR2477583A1 - Double-wrapped elastic yarn - provides method of forming extensible hem for e.g. clothing - Google Patents

Abstract

Wrapped elastic yarn comprises a core of strongly elastic yarn covered with two layers of wrapping in opposite directions. The outer layer comprises a heat-softenable yarn with thermo-adhesive properties. The thermo-adhesive properties become manifest at a temp. lower than the temp. required to degrade the elastic core and the inner wrappings. The yarn provides a method of forming an extensible hem, by folding fabric around the extended yarn and applying heat, causing the outer wrapping to soften and stick the fabric to the inner wrapping. The method is used partic. for disposable non-woven garments.

Description

EXTENSIBLE WIRE AND EXTENSIBLE COMPLEX ARTICLES OBTAINED FROM
FROM SUCH A WIRE.

 The present invention relates to a new type of extensible wrapped yarn, it also relates to complex extensible articles, at least in certain precisely located areas, obtained from such a wrapped yarn.

 Covered stretch yarns have been known for a very long time and consist of a highly elastic core, based on natural rubber or a synthetic elastomer (for example polyurethane yarns such as those sold under the brands LYCRA, RRODASTIC , GLOSPÂN ...) this core being generally covered with two layers of covering, wound in opposite direction (one in direction S and the other in direction Z). Such yarns are commonly used for the manufacture of woven or knitted articles.

 Furthermore, for many applications, particularly in the clothing sector, we are faced with the problem of obtaining localized expandable zones. Thus, in the field of clothing, it is sometimes necessary to create localized stretch zones, for example at the wrists (in the case of surgical gowns) in order to make the seal tightly sealed. The same problem arises in the case of diapers for babies where it is requested that the article has a certain seal on its edges and adapts perfectly to the body of the user.

The solutions used to date to solve this problem consist, for the oldest, in providing a hem at the end of the vertically, hem in which there is an extendable strip for example a rubber. Another solution consists in bringing back in the desired area, for example by sewing, by gluing ... an extensible ribbon
If the solutions used to date give satisfaction from a technical point of view, it must however be recognized that they are of a high cost and / or are difficult to implement.

 However, we have found, and this is what is the subject of the present invention, a new type of extensible wrapped threads which makes it possible to solve this problem and which, moreover, simplifies the process of manufacturing such articles. having to present local extendable areas for example to ensure a certain seal.

 In general, the invention therefore relates to a new type of extensible gimped yarn of the type comprising a core consisting of a highly elastic yarn, based on yarn of natural rubber or synthetic elastomer, covered with two layers of gimping. wound in the opposite direction, this wire being characterized in that the outer covering layer is constituted by a hot-melt wire having iron-on properties capable of being revealed at a temperature below the degradation temperatures of the extendable friend yarn and the yarn forming the first covering layer.

In a preferred embodiment of the invention, use will be made
- as a highly extensible yarn, an elastomeric yarn based on polyurethane such as that sold under the brand LYCRA,
as a first covering thread surrounding the extensible core, a chemical thread, for example based on polyamide 6 or 66, polyester or the like,
- As external covering yarn a chemical yarn having a melting point lower than the first covering yarn, for example a yarn based on a copolyamide 6 such as that marketed under the name Grillon.

 Advantageously, the wrapped wire according to the invention is produced in the conventional manner on a hollow pin mill, the wrapping operation being carried out while keeping the highly elastic thread under tension and the first wrapping layer being formed with contiguous turns. Advantageously, the second covering layer based on the hot-melt wire, the layer which is deposited in the opposite direction to the first, will be deposited with a lower recovery rate than the previous one.

 If the first covering layer is advantageously made from a multifilament chemical yarn with continuous strands, it is obvious; that this is not limiting and that, if necessary, a yarn could be used to make this first covering layer. fibers based on natural material and / or synthetic fibers.

 Of course, the various constituents of the wire confirms the invention may be different from those mentioned above, in particular depending on the applications envisaged, for example the desired degree of extensibility. However, in accordance with the invention, the external fusible covering wire should always have fusible properties compatible both with the nature of the first covering wire and with the nature of the material which must be made extensible.

 The invention also relates to complex articles having determined zones of extensibility obtained using the above-mentioned wire.

Such articles are characterized by the fact that, in the areas where they must have a certain extensibility, of two superimposed layers of material (for example fabric, nonwoven, film ...) at least one thread
according to the invention being interposed transversely between these two layers and the assembly being heat treated so as to cause the fusion of the external covering wire and the bonding of the internal covering wire by this material with the covering layers.

The invention and the advantages which it brings will however be better understood thanks to the example of embodiment given below example which is illustrated by the appended diagrams in which
FIG. 1 schematically illustrates in perspective a wire produced in accordance with the invention in the energized state,
- Figures 2 and 3 are respectively schematic perspective views illustrating an article made from the wire according to the invention on the one hand in the stretched state (Figure 2) and, on the other hand, in the state relaxed (Figure 3),
FIGS. 4 and 5 are respectively sections along the axis AA of FIGS. 2 and 3,
- Figure 6 schematically illustrates in perspective a made-up article produced in accordance with the invention.

The wire produced in accordance with the invention is obtained in a conventional manner on a covering machine and is composed
- a core 1 based on an elastomeric wire surrounded by two layers of wrapping wound in opposite directions 2, 3.

 According to the invention, the outer covering layer 3 is based on a hot-melt material having fusible properties capable of being revealed at a temperature below the temperatures at which the wires 1 and 2 are liable to degrade.

In an exemplary embodiment, the wire according to the invention will be constituted
- as a highly extensible core thread 1 of a
LYCRA having a title, in the relaxed state of 2500 decitex. Such a wire has a maximum elongation capacity of the order of 600%.

- as covering thread 2 a polyamide 6-based thread of 156 decitex, 34 strands, 0 twist turns; the wrapping twist is 700 turns per meter Z direction, this wrapping being carried out under tension of the core wire which is stretched during this operation by 400%,
- As second wrapping 3 a hot melt cricket wire having a title of 235 decitex and comprising 20 strands; the wrapping tension of wire 3 is 500 turns in direction Z.

 Thanks to such a wrapped yarn, it is possible to produce complex articles having localized stretch zones.

Such items are illustrated in Figures 2, 3, 4, 5 and 6.

 These items are obtained in the following manner.

 In the areas where it is desired to obtain a certain extensibility, for example at the end of a sleeve of a blouse to be thrown, there is interposed between two layers 5, 6 of the material constituting the article a thread conforming to the invention. For example, as illustrated in FIGS. 2 and 3, the material is folded at its end so as to form the two layers 5, 6 and between these two layers is interposed, a wire conforming to the invention maintained under tension, this wire having a width corresponding to that of the flat article. The complex thus formed is subjected to a heat treatment which results in the melting of the hot-melt wire 3 which causes bonding between the first covering wire 2 and the outer layers 5, 6.

When the tension is released (FIGS. 3 and 5) the extensible wire 1 contracts which causes the tightening of the complex 5, 6.

 Using the thread given by way of example previously, it was thus possible to produce disposable articles such as blouses from non-woven tablecloths sold under the brand BIDIM. It was found that the hems produced as described above were perfectly resistant, exhibited very great extensibility and ensured perfect sealing. In addition, it was found that the resistance to repeated elastic traction and return was very good, this mistletoe can be explained by the fact that the covering thread 2 is perfectly linked to the outer layers 5, 6 while it is not not secured to the extensible core 1 and therefore it practically forms a protective sheath around this wire.

Furthermore, the bonding points obtained by means of the covering thread 3 also promote the elastic power taken into account because they do not form a continuous surface but are, on the contrary, spaced from one another.

 Such a material, as illustrated in FIG. 6, can be used to make clothes, for example, as said work coats previously. Thanks to the embodiment described above, for example at the end of a sleeve a highly extendable zone 10 allowing the passage of the hand 11 and which encloses the wrist of the user.

 Of course, the invention is not limited to the applications mentioned above but can also be supported as a multitude of other uses. Thus, one could for example use the wrapped yarn according to the invention to produce sachets comprising, near their opening, an extensible part ensuring automatic closing; any pleated articles, the pleats being obtained automatically by virtue of the power of withdrawal of the extensible element.

Likewise, it is possible, depending on the desired applications, to use more than one wire according to the invention to allow the extensibility and the connection to be given, for example two, three or four wires arranged parallel to each other. next to the others. Finally, by virtue of such an embodiment, it is also possible to produce complex articles, for example textile articles with pockets comprising two external faces connected to one another at spaced intervals, a fibrous sheet which can be incorporated between the connection points.

Thus, diapers for babies could be produced by making a complex consisting of a waterproof sheet superimposed with a fibrous veil, these two elements being connected together or else with a fusible wrapped wire according to the invention, arranged at a spacing corresponding to the width of the layer to be produced, an absorbent fibrous sheet being interposed between the sealed face and the fibrous face.

 In addition to the qualities of extensibility that it makes it possible to communicate, such a wrapped yarn also has the advantage of greatly simplifying the confection given the fact that it is possible, thanks to it, to eliminate sewing zones, the bond being obtained directly by heat sealing.

Claims (3)

 1 / Extensible gimped wire of the type comprising a core 1 consisting of a highly elastic yarn covered with two covering layers 2, 3 wound in opposite directions, characterized in that the external covering layer 3 is constituted by a hot-melt wire having fusible properties capable of being revealed at a temperature below the degradation temperatures of the elastic core wire 1 and of the wire forming the first covering layer 2.  2 / wire according to claim 1 characterized in that  the highly elastic core wire 1 is an elastomeric wire based on polyurethane,  the first covering wire 2 surrounding the extensible core 1 is a chemical wire based on polyamide 6 or 66,  - that the outer covering 3 is a wire based on a copolyamide 6 of low melting point.  3 / Complex articles having zones of determined extensibility, characterized in that they consist, in the zones where they must have a certain extensibility, of two superimposed layers of material, at least one wire according to the invention being interposed transversely between these two layers 5, 6 and the assembly being heat treated so as to cause the fusion of the external covering wire 3 and the bonding of the internal covering wire 2 by this material with the covering layers 5, 6.