FR2858522A1 - Elastic joining procedure for two stretch materials uses foam adhesive pressed between joined edges - Google Patents

Abstract

The procedure consists of employing a foam adhesive (3), e.g. in the form of a double-sided strip, pressed between the overlapping edges of two stretch materials (1, 2) to form a narrow elastic joining strip (4). The pressure applied is between 0.5 and 1.5 bars and at a temperature of 20 - 38 degrees C for materials that stretch in at least one direction and are made from natural and/or synthetic fibres.

Description

METHOD FOR THE ELASTIC BONDING OF TWO EXTENDABLE ETOFS AND ARTICLES

TEXTILES SO OBTAINED

  The present invention relates to the assembly of fabrics and more particularly extensible fabrics, by gluing for the production of textile articles, outerwear, underwear and / or other articles using fabrics or knitwear. having an extension capability in one or two directions.

  Clothes and textile articles are traditionally made using the stitched cut technique. For this purpose, the fabrics or knits, which are in rolls, are cut by means of cutting systems, either manual or computer-assisted, and the flat pieces are then assembled by means of sewing machines, to give clothing or other textile objects in three dimensions.

  Sewing machines, since the nineteenth century, use the technique of thread and needles, the different mechanical movements of the sewing heads to vary the assembly points, and thus the types of sewing. If the seams called lockstitch block the assembly, the majority of other seams retains the possibility of deforming, to maintain the elasticity of fabrics and / or knitwear.

  However, all these seams have the disadvantage of constituting extra thicknesses, beads and hard spots due to the presence of son overlapping overlapping fabrics.

  For about twenty years, bonding techniques have developed. They are used most often to seal on clothing or other items for use in a humid environment.

  Indeed, these assemblies, by design, prevent any elasticity of seams, and if they are made, either by point or net of glue, or by heat input, they generate beads or hard spots, making it very unpleasant wearing near the body of textile articles.

  The invention aims at eliminating the drawbacks of these known assemblies and more particularly proposes a means of assembling two extensible fabrics conferring on the assembly all its expansion capacities included in the assembly zone and without forming in this last of hard points and extra thicknesses other than those resulting from the local superposition of the fabrics.

  To this end, the subject of the invention is a process for the elastic connection of two extensible fabrics, characterized in that it consists in superimposing the parts to be joined between the two fabrics after placing between these parts an adhesive consisting of an acrylic foam and pressing against each other said parts.

  Adhesives consisting of high performance double-sided acrylic foam tapes sold by 3M France under the name 3M VHB, are particularly suitable for the purpose and allow to obtain assemblies without any extra thickness or hard spots and have a remarkable strength the overlapping parts of the fabrics retain their property of extensibility.

  This type of adhesive is mainly recommended for the assembly of rigid substrates made of plastics, glass, metals, concrete, wood and, surprisingly, following tests, this adhesive revealed a very interesting property, in the context of the assembly in superposition of two extensible fabrics, to preserve the extensible character of the assembly zone of the fabrics despite the presence of the adhesive which, migrating in the interstices between fibers ensures perfect adhesion without constituting extra thicknesses and / or hard spots, as can be observed in glue assemblies known in the field of clothing or the like, as was recalled above.

  Other features and advantages will emerge from the following description of embodiments of the invention, a description given by way of example only and with reference to the accompanying drawings in which FIG. 1 illustrates the assembly according to the invention. ; - Figures 2 to 5 illustrate various means of implementing the method of the invention; In FIG. 1 there are shown at 1 and 2 respectively two pieces of fabric partially superimposed along one of their edges, an adhesive 3 being interposed between the fabrics 1, 2 in the superposition zone of said fabrics, consisting of a thin band 4.

  The fabrics 1, 2 are of at least one extensible type and consist of a fabric or knit fabric made from extensible natural or synthetic fibers or blends of these fibers.

  For example, they may be blends of polyamide and elastane fibers, polyester and spandex, cotton and elastane, polyester and polybutylene.

  It may also be mixtures of non-extensible synthetic or natural fibers and synthetic fibers with extensibility properties such as elastane fibers.

  The method of the invention applies to any type of fabric or knit (stitches picked or thrown).

  The adhesive 3 is of a particular type and consists of an acrylic foam.

  The product consists of a double-sided acrylic foam tape marketed by 3M France under the name high performance double-sided foams 3M VHB, and especially the product called acrylic transfer ribbon F-9469PC is particularly suitable for the implementation of the invention.

  Such a ribbon is translucent and has a thickness of 0.13 mm as well as a high shear strength and good resistance to high temperature.

  This adhesive 3 is set up very easily, after separation of its non-stick protective film, on one of the edges of the fabrics 1, 2. After that, a pressure is exerted on the fabrics 1, 2 to the right of the zone 4.

  A simple pressure exerted by hand with a roller is sufficient because the adhesive 3 is very sensitive to pressure. For example, a pressure of the order of 0.5 to 1.5 bar is sufficient, the duration of application of the pressure being very low, almost instantaneous. It should be noted, however, that a higher pressure is likely to improve the contact of the adhesive with the fibers of the fabrics.

  The temperature during the application of the pressure is not critical, the ideal temperature being in the range 20 to 38 C. A temperature above 38 C is not advisable because it would accelerate the process of adhesion to the detriment of diffusion in the assembly zone 4.

  The adhesive, in fact, under pressure, migrates into the mass of the surrounding fibers and occupies virtually the entire area 4 after 72 hours and too high a temperature would fix the adhesive prematurely.

  The maximum strength of the bond is obtained after 72 hours so that it is possible, according to a particularly advantageous advantage of the invention, to possibly undo the assembly in the event of poor workmanship or incorrect positioning of the fabrics, and reassemble correctly before the adhesive is permanently attached. It is then sufficient to reapply the one on the other fabrics and to exert pressure again to reconstitute the bonding.

  It should be noted, moreover, that the fabrics 1, 2 do not require a particular preparation or primer, it is sufficient that their surfaces are clean, dry and uniform. If it turns out that the fabrics are already primed, then it would be necessary to apply, before gluing, an application of pressurized heat to the fabrics in the zone 4 so as to then allow the adhesive 3 to flow. .

  The pressure required for bonding can be carried out as illustrated in FIG. 2 using two plates 5 and 6, one of which, the upper plate 6, is movable and moved facing the other plate by a jack 7, The assembly 3-4 being placed between the trays.

  The bonding pressure can be exerted as illustrated in Figure 3 with the aid of two rollers 8, 9, upper and lower, rotated in opposite directions and pressed elastically towards each other. The gluing is here carried out by the parade, the fabrics 1, 2 being gradually presented in slight superposition between the rollers 8, 9, together with the adhesive tape 3, continuously fed simultaneously with the fabrics 1, 2.

  In Figure 4, there is shown schematically and partially the sewing device of a sewing machine that can be used to assemble the fabrics 1, 2 according to the invention. For this purpose, the fabrics 1, 2 and the adhesive tape 3 are engaged in the same manner as with the device of FIG. 3, between the plate 10 and the presser foot 1 1 of the sewing machine, the assembly being driven by the driving claws 12 of the machine, the needle being of course put out of service.

  In order to properly guide the elements 1, 2 and 3, the conventional S-guide shown in section at 13 in FIG. 5 can be used in order to superimpose in the zone 4 the fabrics 1 and 2 as well as the adhesive tape 3, which is guided by a tubular conduit 14 disposed in the portion S of the guide 13 in the known manner.

  The method of the invention allows for flat layouts without wires or hard spots, the adhesive being very regularly and widely diffused in the mass of the fabric fringes in superposition and not constituting hard clumps.

  This provides an important comfort to wear the garment thus produced.

  The fabrics retain their full extensibility, including at the area of the overlap zone 4.

  Furthermore, the adhesive 3 has a high resistance to water, which allows the manufacture of eg swimwear or sports suits that are worn close to the body, with a negative ease.

Claims (7)

  1. A method of elastic connection of two extensible fabrics (1, 2) characterized in that it consists in superimposing the parts to be secured of the two fabrics (1, 2) after placement between these parts of an adhesive (3) consisting of an acrylic foam and pressing against each other said parts.   2. Method according to claim 1, characterized in that the adhesive (3) is selected from the group of double-sided acrylic high performance foam tapes marketed under the name 3M VHB, by the company 3M France, especially under the reference F -9469PC.   3. Method according to claim 1 or 2, characterized in that the pressure exerted on said parts to be assembled is of the order of 0.5 bar to 1.5 bar.   4. Method according to one of claims 1 to 3, characterized in that the pressure is applied at a temperature of the order of 20 to 38 C.   5. Method according to one of claims 1 to 4, characterized in that the fabrics (1, 2) are selected from the group consisting of fabrics and knits capable of extensibility in at least one direction and formed from natural and / or synthetic fibers.   6. Method according to claim 5, characterized in that the fabrics (1, 2) consist of fiber mixtures selected from the group consisting of polyamide fibers, polyester elastane and polybutylenes.   7. Apparel and textile articles obtained by the process   according to any one of claims 1 to 6.