FR3042512A1 - TRICOTE TEXTILE GRILLE - Google Patents

Abstract

This knitted textile grid integrates voluminized son (206), the diameter of which is between 1.5 and 5 millimeters, in the production direction and / or in the cross direction or obliquely.

Description

FIELD OF THE INVENTION The invention is in the field of the production of knitted textile structures in the form of grids, more particularly intended to be integrated within composite structures implemented in particular in the field of electrical insulation, but also thermal and acoustic.

PRIOR STATE OF THE TECHNIQUE

The implementation of textile structures in the context of reinforcing elements on the one hand, or as a coating medium for adhesives or electrical insulating materials on the other hand is widely known. Such an integration makes it possible, in a known manner, to confer on the structures in which such textile elements are integrated various forms, on the one hand, and properties, in particular mechanical and insulating properties of a great diversity on the other hand. .

Traditionally, such textile elements are generally made of woven or nonwoven, most of them having a flat surface with few reliefs emerging from the plane constituted by said surface. Due to this limited relief, experience shows that their integration into the structures to be reinforced or isolated is limited, which can lead to uncoupling or delamination, resulting in a significant loss of desired performance, or even deterioration of properties. end products.

In order to overcome these drawbacks, it has been proposed to multiply the textile structures or the stack of several layers, in particular of coating within the same final product. This solution complicates the manufacturing processes, making them more difficult to automate and generating additional costs. The invention proposes a technical solution to overcome or in any case substantially reduce these disadvantages.

SUMMARY OF THE INVENTION The invention thus proposes a textile structure, in this case consisting of a knitted grid, incorporating voluminized son, advantageously of low density, and having a large diameter relative to the constituent son of the constituent support structure of the grid, in order to create relief with respect to the plane in which the support grid is inscribed.

Voluminized wire means son having a diameter much greater than that of the constituent son of the support structure constituting the grid.

Typically, the diameter of voluminized wires is in a range between 1.5 and 5 millimeters. Indeed, the implementation of voluminized son with a diameter of less than 1.5 millimeters is of no interest, since both the desired objective of increasing the relief of the textile structure is not achieved.

If, on the other hand, the diameter of the voluminized wires exceeds 5 millimeters, the risk is incurred during the production of the grid to flatten said wires, thus again affecting the desired objective of giving relief to the textile grid. .

According to the invention, this knitted textile grid is made by the so-called jet mesh technology, in particular on a Rachel multi-barbed machine with or without a framer (Karl-Mayer, Liba, Cornez or others), or on a double-knit stitch loom. needle bed.

The implementation of this jagged mesh technology makes it possible, in a known manner, to integrate additional threads within a textile structure, and in this case such voluminized threads, not only in the production sense and / or in the cross-direction, but also in the form of partial frames, that is to say, to have more complex patterns than a simple grid.

In addition, because of the technology used, it is possible, during the realization of the grid, to move the voluminized son from different angles by adjusting the radius of curvature of the son, their voltage and their flow , so as to obtain evolutions in the form of curves, extending on the one hand, in the plane of the grid itself, and on the other hand, in relief relative to this plane, either because of the inherent relief to the size of the wire itself, either because of the armor used, especially when double needle technology is implemented.

Furthermore, because of the use of voluminized son, one can have a low density, nevertheless generating the thickness required for the application of the grid of the invention, without increasing the weight of the final structure within which such a grid is likely to be integrated.

The voluminized son are advantageously made of fibers of mineral material, and in particular glass fibers or basalt fibers for electrically insulating composites. However, it can be envisaged to use synthetic, polymer-type (polyester) yarns. , polyethylene, polypropylene, aramid or meta-aramid .., or natural fibers such as cotton or lia

As a corollary, the binding yarns, in known manner ensuring the connection between the warp yarns and the weft yarns in order to define the support grid, may be made of glass fibers, polyester fibers or aramid fibers, such as, for example, made of by the company DUPONT DE NEMOURS and marketed under the trademark NOMEX®, in order to give them heat resistance, to optimize the resistance of the textile grid thus obtained to heat treatments or impregnations generating an increase in temperature.

Advantageously, the openings of the grid constituting the invention, most often more or less close to a square shape, although this accuracy is not limiting, have a diameter or a length of side, and generally at minus a dimension of between 2 and 60 millimeters, in particular to limit the weight and to allow good penetration of resin, when the grid is intended to be subsequently coated.

Advantageously, the voluminized son have a title of between 300 and 4800 Tex for glass. If they are made of synthetic material or based on natural fibers, this title is between 1000 and 7000 dtex. The choice of these different titles is dictated by the desire to reach the volume of said desired son ..

According to the invention, the textile grid has a density of between 100 and 2,000 g / m2. The thickness of the grid is between 0.8 and 10 millimeters to ensure the reinforcement or the desired electrical, thermal or acoustic insulation characteristics.

BRIEF DESCRIPTION OF THE FIGURES

The manner in which the invention can be realized and the advantages which result therefrom will emerge more clearly from the following exemplary embodiments, given as an indication and not a limitation to the accompanying figures.

Figure 1 is a schematic representation illustrating a support grid of traditional invoice, incorporating different modes of binding.

Figure 2 is a schematic representation of a grid according to the invention, incorporating a particular embodiment of integration voluminized son.

FIG. 3a is a diagrammatic representation of another embodiment of the invention in which the voluminized wires are introduced in a transverse frame so as to be superimposed on the base support grid, FIG. 3b is a diagrammatic view of section.

FIG. 4a is a schematic representation of another embodiment of the invention in which the voluminized wires adopt a configuration similar to a sinusoid, of which FIG. 4b is a diagrammatic representation in section.

FIG. 5 is a schematic representation of another embodiment of the invention, in which the voluminised wires are arranged in the production direction, as in FIG. 2, but in superposition of the constituent weft wires of the support grid. .

Figure 6 is a schematic representation of yet another embodiment of the invention wherein the voluminized son are oriented obliquely to the production direction.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 therefore shows a knitted textile grid illustrating the state of the art. This conventionally comprises warp yarns (104) and weft yarns (102, 103) defining, after bonding with the warp yarns, openings (105).

The binding yarns thus ensuring the cohesion of the grid, can provide a link of the catenary type (101a) or knit type (101b), the choice of the binding yarn, and more particularly the armor binding yarn, dependent blockage more or less important that it is desired to print the constituent son of the grid, and therefore corollary, its deformation capacity.

Figure 2 shows a first embodiment of the invention. In this, one introduces in the grid of the type of that described in relation with FIG. 1, voluminized wires (206), in capstan that is to say oriented in the direction of production, between the weft threads (204). .

In this embodiment, these bulky yarns are sandwiched between the yarns under yarns (202, 203) forming sinusoid-like shapes. These voluminized wires (206) are held in position between the partial frames formed by the wires (202) and (203). It is indeed possible to observe in FIG. 2 the passage of said volumetric threads respectively over the wire (203) and below the wire (202). The reference (201) shows the binding threads.

These volumetric threads are typically made of glass fibers, in particular glass rovings with a titer of between 300 and 4800 tex. They have a diameter out of stress of the order of 3 millimeters.

According to Figure 3a, showing another embodiment of the invention, the voluminized son (306) are introduced in transverse frame, in order to superpose or replace some son of the basic structure. It is possible to observe in fact, in FIG. 3b, diagrammatically illustrating a sectional view of FIG. 3a, these wires (306) forming a relief with respect to the general plane constituted by the base grid.

These voluminized son are secured to the base grid by the binding son (301).

In FIG. 4, illustrating another embodiment of the invention, the voluminised wires (406) evolve in a more complex path than in FIGS. 2 and 3a. Indeed, they adopt an alternation of curves by the partial frames and the radii of curvature of the turning zones obtained without tension. This structure is made possible by the setting in game of guide bars, moving laterally, made possible by the jetty mesh technology. The substantially symmetrical arrangements of the evolutions of the voluminised wires (406) with respect to the warp threads (404) are thus observed. The reference numerals (401) denote the binding yarns.

As a result, as shown in FIG. 4b, a relief of the resulting structure is obtained, more important than in FIG. 3b, inherent not only in the diameter of said volumised wires, but also in the armor used.

FIG. 5 illustrates another embodiment of the invention, in which the voluminised wires (506) are, again, oriented rectilinearly in the direction of production. These threads are mounted in capstan, but inserted between the tie-wire columns (501) of the basic structure

FIG. 6 is an embodiment illustrating a more complex path of the voluminised wires (606), in this case alternating obliques with respect to the production direction. The reference (601) shows the binding threads.

To do this, on a loom Rachel 4 bars, the glass rovings are mounted in capstan on the bar 3, the partial frames are mounted in bar 2 and 4, and the binding wire being mounted in bar 1

During manufacture, the binding yarns form a chain or possibly a bonding of simple knit type that will allow holding all the partial frames. The various elements constituting the grid, in this case, partial weft, binding yarns, capstan, intersect at the crossing level called nodes, at which the binding takes place effectively, and conferring on the structure a mechanical strength. .

The bonding of the basic structure using jetty mesh technology and the choice of binding (chain, knitting, etc ...) make it possible to bind the bulky threads without constraining them too much, so that they retain a volume so that the structure itself has the desired relief.

The variants described in connection with FIGS. 3 and 4 remain flexible, even after coating, because of the implementation of binding which reduces the volume periodically at the junction points and gives a possibility of a smaller radius of curvature at the locations link.

At the level of the binding stitches by the binding yarn, the tension applied on the binding yarn is adjustable, in a manner known in the context of the technology implemented with a stitching knit. This adjustment of the tension is ensured by the donors of threads which adjust the length of yarn absorbed. This adjustment thus makes it possible to apply and control a low voltage, which has the consequence of preserving the relief on the textile given by the voluminised wires, while ensuring lower radii of curvature for the son impregnated with resins.

In addition, during the passage of the rovings in the knitting machine, the latter are guided and prepositioned, typically with the help of tubes placed at the guide rods.

Because of the choice of voluminized fibers on the one hand, and the technique used, in this case, mesh technology thrown on the other hand, the thickness of the grid thus obtained can be greater than 80% or 300% compared to a conventional grid.

It is thus conceivable that, because of the technology used, a fabric structure with a relief exacerbated in a simple manner, capable of being integrated into reinforcement or electrical insulation structures for example, or thermal or acoustic, is obtained. ..

Claims (10)

claims 1. knitted textile grid integrating in the direction of production and / or in the cross or oblique direction voluminized son (206, 306, 406, 506, 606), whose diameter is between 1.5 and 5 millimeters. 2. knitted textile grid according to claim 1, characterized in that the grid is obtained by the technology knit discarded with or without a stroller. 3. knitted textile grid according to claim 1, characterized in that the grid is obtained by the technology meshed discarded double loom. 4. Knitted textile grid according to one of claims 1 to 3, characterized in that the voluminized son are made of mineral fiber material, including glass fiber or basalt fiber. 5. knitted textile grid according to claim 4, characterized in that the voluminized son have a title between 300 and 4800 tex, 6. Knitted textile grid according to one of claims 1 to 3, characterized in that the voluminized son are made from synthetic fibers, in particular of the polymer type, selected from the group comprising polyester, polyethylene, polypropylene, aramids or meta-aramid. 7. knitted textile grid according to one of claims 1 to 3, characterized in that the voluminized son are made from natural fibers, especially selected from the group consisting of cotton and linen. 8. knitted textile grid according to one of claims 6 and 7, characterized in that the voluminized son have a title between 1000 and 7000 dtex. 9. knitted textile grid according to one of claims 1 to 8, characterized in that the binding son (201, 301, 401, 501, 601) are made of glass fibers, polyester fibers or aramid fibers . 10. knitted textile grid according to one of claims 1 to 9, characterized in that it defines openings, one of which 4ps dimensions & u less has a length of between 2 and 60 millimeters.