EP0818567A1 - Composite yarn for making elastic knitted support articles - Google Patents

Abstract

The stretch fabric is a warp knit with a warp (16) composed of a stretch core (17) cladded (19) with a yarn of micro fibres. The yarn for the stitches is a combination of an elastic thread (1), a cotton thread (2) and a synthetic filament (3) of micro fibres which are interlaced at intervals with the cotton (2) and stretch (1) threads. The stretch threads are extended by at least 100%.

Description

The present invention relates to an elastic article of compression / knitted compression.

Conventionally, a compression / compression article is characterized by the fact that it exerts physical compression on a outer member of the human body, this compression can be measured according to standardized methods, for example French standard AFNOR G 30.102 - October 1986 (and other standards such as DIN en Germany, BSI in Great Britain, etc.). These measurement methods give as results values expressed for example in mmHg or hPa.

It is generally accepted at present that a low, for be considered a "compression stocking", must exert a minimum compression of 10 mmHg measured according to the AFNOR G standard. 30.102.

Nowadays, compression knitted articles such as socks and stockings are most often knitted using only synthetic yarns, which has the disadvantage of not being not provide satisfactory thermal comfort to the knitted article. In Indeed, such knitted articles do not provide evacuation of the sweating in summer, resulting in a feeling of humidity, and do not create air buffer layer ensuring in winter a thermal insulation effect, therefore protection against the cold.

It has also been proposed to produce such articles according to a weft knit structure, using elastic weft yarn with cotton covering and forming the stitches using a synthetic thread especially polyamide. Weft cotton, mainly in contact with the skin, certainly absorbs sweat, but does not evacuate it, being not or only slightly in contact with the outside air. In addition, cotton does not participate, in this configuration, in the creation of a screen protective against the cold.

The present invention relates to an elastic article of compression / knitted compression offering, in addition to thermal comfort improved, great softness, an original aesthetic aspect as well that a good longitudinal adaptability of the article.

The elastic compression / compression article in accordance with the invention is made in a woven knitted structure, with a weft thread formed of a core of elastic thread with covering by a synthetic thread with microfibers, for example a polyamide yarn 20 dtex / 20 strands, 33 dtex / 34 strands, 44 dtex / 34 strands or 78 dtex / 68 strands, and with a mesh consisting of a composite wire comprising in combination, a wire elastic, synthetic microfiber yarn and cotton yarn, the microfibers of synthetic yarn being linked by interlacing, by intervals, with the cotton thread and with the elastic thread, the latter being at least 100% elongated.

Interlacing of microfibers of synthetic yarn at intervals with cotton thread and with elastic thread, ensures the cohesion of the three constituent materials, which allows knitting these three materials simultaneously and easily, in the form of a composite wire which can have a fairly low total titer in order to obtain a light article.

Preferably, the elastic thread is elongated by at least 200%, advantageously between 200 and 300% and more particularly between around 215 and 265% during said interlacing at intervals.

According to a preferred embodiment, the three wires constituting the composite wire are interlaced at intervals by air jets, by passage of the three constituent wires of the composite wire, the elastic wire being elongated, in a wire interlacing machine of type known in self, comprising a tangentially acting air nozzle, with resonance, on the wires to be assembled.

Preferably, the constituent wires of the composite wire are assembled by interlacing at intervals of less than 4 cm, and more particularly at intervals of less than 2 cm in the case of wires composites for knitting compression articles formed by example of an elastic thread of 22 or 44 dtex, of a combed cotton thread Nm 80 to Nm 224 and a polyamide microfiber yarn from 20 to 78 dtex.

la figure 1 est une photographie agrandie d'un fil composite, le fil élastique étant détendu;

la figure 2 représente le procédé de fabrication du fil composite suivant la figure 1;

la figure 3 représente une structure de tricot tramé conforme à l'invention, réalisée à l'aide d'un tel fil composite;

la figure 4 représente le principe d'un fil de trame guipé utilisé dans le tricot de la figure 3.

Referring to the appended schematic drawings, a description will be given below in more detail of the composite yarn used in the knitted article according to the invention, its manufacturing process as well as a woven knitted structure which can be produced with the use of such a composite wire; on the drawings:

Figure 1 is an enlarged photograph of a composite yarn, the elastic yarn being relaxed;

FIG. 2 represents the process for manufacturing the composite wire according to FIG. 1;

FIG. 3 represents a woven knitted structure according to the invention, produced using such a composite yarn;

FIG. 4 represents the principle of a covered weft thread used in the knitting of FIG. 3.

The composite wire as illustrated in Figure 1 consists of a wire elastic 1, made of natural or synthetic rubber, of cotton thread 2 and a synthetic yarn 3 with microfibers, in particular made of polyamide. The three wires 1, 2, 3 are assembled in the form of a composite wire by interlacing of the microfibers of yarn 3, at intervals, with the yarn elastic 1 and cotton thread 2, this interlacing being carried out while the elastic thread 1 is elongated by at least 100% and preferably by at least 200%. As shown clearly in Figure 1, the interlacing microfibers of yarn 3 with the other two yarns 1 and 2 only takes place by intervals, in points 4. It is also recognized in the figure, that the microfiber yarn 3 is inflated between the interlacing points 4, which appears particularly when the elastic thread 1 is relaxed, as this is the case in Figure 1, the cotton thread 2 then describing a shape wavy.

According to FIG. 2, the manufacture of the composite wire illustrated by the Figure 1 is performed on an air jet interleaver commonly called assembly machine or wrapping machine by air jet. Such machines which are marketed for example by ICBT, FADIS or JUIDICI Companies have the particularity to include an air jet nozzle as marketed for example by the HEBERLEIN Company, producing an oriented air jet tangentially to the moving wire, acting with effect of resonance.

• un fil élastique 1 de caoutchouc synthétique de 22 ou 44 dtex
• un fil coton peigné 2 de Nm 159 ou Nm 120, et
• un fil polyamide 3 à microfibres de 44 dtex/34 brins FT, dans les plages données ci-après : 2,15 < ω2ω1 < 2,65 1,15 < ω3ω2 < 1,07 1,20 < ω4ω3 < 1,40 0,880 < ω5ω4 < 0,997

For the production of the composite wire from the three wires 1, 2 and 3, the elastic wire 1 is removed from a reserve by a first call device 7 with positive drive, for example a roller in contact with the winding d 'a reserve coil 6, rotating at a circumferential speed ωl, to then pass it on a second call device 8 with positive drive, for example a roller, rotating at a circumferential speed ω2 greater than ω1. At the same time as the wire 1 which thus undergoes, between the call devices 7 and 8, an elongation corresponding to the difference in the speeds ω1 and ω2, the call device 8 removes two reserves 9 and 10 , respectively wire 2 and wire 3, the three wires 1, 2 and 3 passing from the second call device 8 to a third call device 11 with positive drive, for example a roller, driven at a circumferential speed ω3 greater than ω2. From the call device 11, the three wires pass, through the air jet nozzle 5, over a fourth call device 12 with positive drive, for example a roller rotating at a circumferential speed ω4 greater than ω3, before that the composite thread produced in the air jet nozzle 5 by assembling the three threads 1, 2, 3, by interlacing at intervals the microfibers of the thread 3 with the threads 1 and 2, is wound on a reel 13 by a device positive drive 14, for example a roller in contact with the winding of the coil 13, rotating at a circumferential speed ω5 less than ω4. Preferably, the speed ratios ω1 to ω5 can be chosen in the example of a composite wire composed of

• an elastic thread 1 of synthetic rubber of 22 or 44 dtex
• a combed cotton thread 2 of Nm 159 or Nm 120, and
• a 44 dtex / 34 strand FT polyamide 3 microfiber yarn in the ranges given below: 2.15 < ω2 ω1 <2.65 1.15 < ω3 ω2 <1.07 1.20 < ω4 ω3 <1.40 0.880 < ω5 ω4 <0.997

Figure 3 very schematically illustrates a knitting structure screening screen article according to the invention, in particular of stockings or socks, made with a composite thread according to Figure 1 for stitches 15 and with a weft 16 which will be described in more detail with reference to FIG. 4. FIG. 3 represents the internal face of the woven knit, i.e. the side which, when in use (when worn) found in contact with the skin, the external face being in contact with Ambiant air.

The outward-facing areas, that is to say, are indicated by "a" not in contact with the skin, and in "b" the areas in contact with the skin. The cotton of the composite yarn being in contact with the skin only in areas b, so very punctually, absorbs the sweat from the skin surface. By capillarity, this humidity propagates on the entire cotton thread. The latter, mainly located on the outer face of the knitted fabric, composed mainly of mesh yarns, effectively evaporates perspiration. We get from this makes optimal comfort in summer.

In addition, the fibrils of the cotton yarn and the unitary filaments of the cotton yarn mesh microfibers create a protective screen against drafts cold air in winter, constituting a buffer layer of air which insulates the ambient air legs, which ensures good comfort in winter.

FIG. 4 represents a preferred embodiment of the wire weft 16 of the weft knit according to FIG. 3. The weft thread 16 comprises a core 17 constituted by an elastic thread, made of natural rubber or synthetic, surrounded by double wrapping, i.e. an inner wrapping 18 in one direction and outer wrapping 19 in the opposite direction, consisting of a microfiber yarn, for example a polyamide 20 yarn dtex / 20 strands, 33 dtex / 34 strands, 44 dtex / 34 strands or 78 dtex / 68 strands.

This double covering with external covering by microfibers has for aim to make it comfortable to wear, in the case of compression articles developing a high pressure level. Indeed, the contact of the inner face of the knitted fabric with the skin being done mainly with the screens (zones A according to FIG. 3), contact with the skin is ensured, for the weft, by a surface covered with microfibers. This ensures a gentle contact, important especially for articles of high pressure restraint, as it facilitates donning articles, for example in the case of stockings or socks.

It goes without saying that the embodiment shown and described has not been given as an illustrative and nonlimiting example and that many modifications and variants are possible within the framework of the invention.

Thus, the composite yarn can be produced in particular with different titles of the elementary threads, variations being possible in this case with regard to the gear ratios over the different stages of wire assembly, to allow adaptation optimal under the conditions of use (knitting) of the yarn. Thread synthetic 3 with microfibers could also consist of synthetic materials other than polyamide.

Claims (7)

Knitted elastic compression / compression article, characterized by the fact that it is made in a knitted structure woven with a weft (16) formed of a core (17) in elastic wrapped yarn (19) per thread with microfibers and with a mesh wire (15) consisting of a wire composite comprising, in combination, an elastic thread (1), a thread cotton (2) and a synthetic thread (3) with microfibers, the microfibers of the thread synthetic (3) being linked by interlacing at intervals (4) with the cotton thread (2) and with the elastic thread (1), the latter being extended by minus 100%. Article according to claim 1, characterized in that the microfibers of synthetic yarn (3) are linked with cotton yarn (2) and with the elastic thread (1), the latter being elongated by at least 200%. Article according to claim 2, characterized in that the microfibers of synthetic yarn (3) are linked with cotton yarn (2) and with the elastic thread (1), the latter being elongated between 200 and 300%. Article according to claim 3, characterized in that the microfibers of synthetic yarn (3) are linked with cotton yarn (2) and with the elastic thread (1), the latter being elongated between 215 and 265%. Article according to any one of the claims previous, characterized in that the microfibers of the yarn synthetic (3) are linked by interlacing at intervals by air jet with the cotton thread (2) and with the elastic thread (1). Article according to any one of the claims previous, characterized in that the microfibers of the yarn synthetic (3) are linked with cotton thread (2) and with elastic thread (1) by interlacing at intervals of less than 4 cm, the thread elastic (1) being elongated. Article according to claim 6, characterized in that the microfibers of synthetic yarn (3) are linked with cotton yarn (2) and with the elastic thread (1) by interlacing at intervals less than 2 cm.

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