EP1111114B1 - Textile mesh with a reduced thickness - Google Patents

Abstract

A textile grill, comprises at least two warp layers and at least one weft layer of nonwoven fabric. An adhesive holds the layers together where they intersect. The grill has a performance level (TP) of ≥ 30, given a specific relationship. A textile grill, comprises at least two warp layers and at least one weft layer of nonwoven fabric. An adhesive holds the layers together where they intersect. The grill has a performance level (TP) given by equation (I). TP = S x 100 divided by ( T x E x C) ≥ 30 (I) C = factor for the adhesive, = 0-1; E = grill thickness (mm); S = surface area of intersection points (mm<2>); and T = quality of the warp and weft fibers (g/km). Independent claims are included for: (a) an industrial product including the above grill; and (b) the manufacture of the grill, comprises impregnating the assembled layers with adhesive and pressing the grill before the adhesive has dried.

Description

The present invention relates to the general technical field of textile grids formed of a network of warp and weft son held in place by bonding at the crossover point of the son, such grids intervening in particular as reinforcements or supports in various industrial applications .

The present invention relates to a textile grid formed by a network of crossed or superposed nonwoven threads comprising at least two sheets of warp threads between which is interposed at least one sheet of weft threads, the warp and weft threads being linked between they at their crossing by a binder creating a series of points of collage.

The present invention also relates to any finished or unfinished industrial product incorporating a textile grid according to the invention.

The present invention also relates to a method of manufacturing a textile grid in which a network of crossed or non-woven superposed yarns is produced comprising at least two sheets of warp yarns between which is interposed at least one sheet of weft yarns, and the network of son is coated with a binder to ensure the connection of the weft and warp threads between them.

It is already known to produce industrially grids formed of a network of nonwoven cross threads, the son being glued together at their cross points by impregnation with a binder, the kind of thermoplastic glue or other. Known grids, such as those illustrated for example in figure 1 , implement at least two sheets of warp A, B, superimposed or shifted, each pair of sheets A, B, having interposed between them at least one web C of weft son. According to these known embodiments, the warp yarns 1 and the weft yarns 2 are linked together at their crossing 3 by a binder 4 creating a series of bonding points in order to obtain a textile grid having a finite and stable structure on the mechanical plane.

Grids made according to this technique are generally satisfactory and serve as reinforcements or supports in very diverse technical fields such as for example without limitation, in the building industry, as a support for parquet and ceramic or wall coverings and carpets, in the paper industry, or as a reinforcing element in synthetic foams or the like.

Nevertheless, it appears that the textile grids known to date suffer from a certain number of disadvantages and in particular from a drawback related to the relatively large and mainly very irregular thickness of the grid. In fact, the method of manufacturing the known grids involves a simple coating of a thermoplastic adhesive or binder, of the PVC or PVA type, for example, without any other complementary operation. As a result, the resulting textile grids have a relatively large thickness whatever the nature, the type, the number of son used leading to a relative lack of flexibility of the grid obtained. In addition, the thickness of the textile grids known today is particularly irregular because of the existence of a relief at the crossing points of the warp 1 and weft son 2. The presence of such irregularities at the level of Textile grids of the prior art obviously have a number of disadvantages on the industrial level, and particularly in certain specific applications.

In addition, it turns out that the conventional textile grids have a certain weakness of the mechanical strength of the network of son bonded at the bonding points or cross between the warp and weft son.

Finally, the prior art textile grids appear to involve a relatively high consumption of the glue or thermoplastic binder used, particularly if it is desired to try to reinforce the mechanical strength of the wire network at the crossing points. . This leads to increase the cost of the products obtained, which is a disadvantage on the industrial level.

In an attempt to remedy at least in part the disadvantages listed above, it has already been envisaged, in particular in the patent GB-1463969 , to produce a reduced thickness textile grid in which the redistribution of the son network is obtained by compression, and in particular by calendering the grid in order to flatten it. The calendered grid obtained effectively has a reduced thickness, for example of the order of 200 to 150 micrometers, in comparison with conventional grids of the prior art. Such a reduction in thickness by calendering the textile grid is nevertheless accompanied by a partial destruction of the structure of the bonding points between the warp and weft threads, so that the general mechanical strength at break of these points is greatly reduced in comparison with conventional grids. Furthermore, the calendering compression technique of the textile grid is not accompanied by a reduction in the amount of glue used. In total, the calendered textile grids, in addition to the relative complexity and difficulty of obtaining the product on the industrial level, suffer from a certain number of disadvantages making their use limited or even inappropriate in certain applications.

The objects assigned to the present invention therefore aim to remedy the various disadvantages of textile grids of the prior art. mentioned above, and to propose a new textile grid formed by a network of cross threads or nonwoven superimposed which has a reduced overall thickness and regular, as well as a good mechanical strength, while being of a reduced manufacturing cost.

Another object of the invention is to provide a novel textile grid having particularly high general performance characteristics in terms of mechanical strength, flexibility and bulk.

Another object of the invention is to propose a new textile grid of particularly small and regular thickness.

Another object of the invention is to propose a new industrial product incorporating the textile grid according to the invention.

A complementary object of the invention is to propose a novel method of manufacturing a textile grid formed by a network of cross son or superposed nonwoven particularly simple to achieve.

dans laquelle :

S =

Surface des points de collage en mm²,

T =

Titre des fils de trame et chaîne en gr / km,

E =

Epaisseur moyenne de la grille en mm,

C =

Taux de colle compris entre 0 et 1.

The objects assigned to the invention are achieved by means of a textile grid formed by a network of nonwoven cross threads comprising at least two sheets of warp threads between which is interposed at least one sheet of weft threads, warp and weft yarns being bound together at their crossings by a binder creating a series of bonding points, characterized by a performance ratio (TP) of greater than 30, the performance ratio being calculated according to the formula: $$\mathrm{TP}\mathrm{=}\frac{\mathrm{S}}{\mathrm{T\; x\; E\; x\; C}}\mathrm{x}\mathrm{100}$$

in which :

S =

Surface of bonding points in mm ² ,

T =

Title of weft and warp threads in gr / km,

E =

Average thickness of the grid in mm,

C =

Glue ratio between 0 and 1.

• on réalise un réseau de fils croisés non tissés comprenant au moins deux nappes de fils de chaîne entre lesquelles est interposée au moins une nappe de fils de trame,
• on imprègne le réseau de fils d'un liant pour assurer la liaison des fils de trame et de chaîne entre eux au niveau de leurs points de croisement,

caractérisé en ce qu'on assure le pressage du réseau de fils avant que la phase de séchage du liant ne soit terminée.The objects assigned to the invention are also achieved by means of a method of manufacturing a textile grid according to the invention in which:

• a network of nonwoven cross-threads comprising at least two sheets of warp threads between which is interposed at least one sheet of weft threads,
• the thread network is impregnated with a binder to ensure the connection of the weft and warp threads to each other at their crossing points,

characterized in that the pressing of the son network is carried out before the drying phase of the binder is completed.

• La figure 1 illustre selon une vue en coupe partielle, un détail de réalisation de la structure d'une grille textile de l'art antérieur.
• La figure 2 illustre selon une vue en coupe transversale partielle, un détail de réalisation de la structure d'une grille textile conforme à l'invention.

Other particular objects and advantages of the invention will appear in more detail on reading the description which follows and with the aid of the accompanying drawings below, for purely illustrative and non-limiting purposes in which:

• The figure 1 illustrates in a partial sectional view, a detail of the structure of a textile grid of the prior art.
• The figure 2 illustrates in a partial cross-sectional view, a detail of the structure of a textile grid according to the invention.

According to the invention, as illustrated in figure 2 , the textile grid according to the invention is formed by a network of cross threads or superposed nonwoven comprising at least two plies A, B, of warp yarns 1 between which is interposed at least one ply C of weft threads 2.

As is well known to those skilled in the art, the construction of the network of warp son 1 and weft son 2 is obtained by shifting the warp and weft son without superposition, or on the contrary ensuring a superposition of the wires. In the same way, the network of warp 1 and weft 2 son can be obtained with a crossing of the warp and weft son to 90 ° (square construction) or at a different angular inclination, and for example directional sorting.

By way of non-limiting example, the textile grid according to the invention may be formed by a number of variable threads, which may vary from 0.5 thread per centimeter to 8 threads per centimeter for the warp threads, and for the weft threads that may vary. for example 0.5 thread per centimeter to 5 threads per centimeter.

Without limitation, and as is well known to those skilled in the art, any type of textile yarn commonly used to date in the production of textile grids can be used, and for example son Silionne type, polyester, cellulosic , aramids or polyamides.

According to the invention, the warp 1 and weft 2 son are interconnected at their crossing 3 by a binder 4 creating a series of bonding points at the intersection of the son network.

Within the meaning of the invention, any binder or glue currently used in the technical field in question may be used, and in particular any binder or thermoplastic glue. Without limitation, the bonding and coating of the son network forming the textile grid according to the invention may be formed by synthetic latexes (SBR, etc.), PVAC, plastisols, PVC, alcohol polyvinyl (PVA), conventional heat-sealing impregnations, polyurethane binders or acrylic binders, for example.

According to the invention, it became apparent that, given the strength of the weft and warp threads used, the structural characteristics of the thread network of the textile grid according to the invention such as the surface of the dots were maintained. as well as the average thickness of the grid and the rate of glue used or present in the mass of the yarns, beyond a minimum value, or in a specific range, were obtained remarkable characteristics of the behavior of the textile grid.

dans laquelle :

S =

Surface des points de collage en mm²,

T =

Titre des fils de trame et chaîne en gr / km,

E =

Epaisseur moyenne de la grille en mm,

C =

Taux de colle compris entre 0 et 1.

The structural characteristics of the textile grid according to the invention can thus be expressed by a performance ratio TP greater than 30, the performance ratio being calculated according to the formula: $$\mathrm{TP}\mathrm{=}\frac{\mathrm{S}}{\mathrm{T\; x\; E\; x\; C}}\mathrm{x}\mathrm{100}$$

in which :

S =

Surface of bonding points in mm ² ,

T =

Title of weft and warp threads in gr / km,

E =

Average thickness of the grid in mm,

C =

Glue ratio between 0 and 1.

A textile grid thus characterized has a reduced thickness, and for example preferably less than 0.175 mm and regular without the existence of a significant relief at the crossing of the warp son 1 and weft 2, while having excellent performance mechanics of the yarn network with glue consumption lower by at least 30% compared to conventional textile grids.

Thus, at crossings, the thickness of the gate is substantially equal to twice the thickness of the single wire out of intersection.

Incidentally, the textile grid obtained has a good flexibility and a small footprint since, in comparison with known conventional textile grids, the film wound on the same coil can be multiplied by two in the case of a textile grid conforming to the invention.

The general characteristics of behavior of the textile grid according to the invention are particularly improved when the performance ratio TP is between 45 and 120.

In the same way, according to the invention, the thickness E will preferably be less than 0.150 mm and even more preferably between 0.150 and 0.06 mm.

The value T is obtained by averaging the titles of the warp and weft threads used: $$\frac{\mathrm{String\; title}+\mathrm{<figure-callout\; id="2"\; label="title\; frame"\; filenames="imgf0001.png"\; state="\{\{state\}\}">title\; frame</figure-callout>}}{2}$$

Table 1 below expresses, in a comparative manner, the measured values, characteristic of a fine grid according to the invention and of a normal grid of the prior art, for the same composition of a network of wires for the same thermoplastic binder for six different compositions of the son networks. Table 1: GRIDS OF THE PRIOR ART GRIDS CONFORMING TO THE INVENTION Wire rack Title thread in gr / 1000m Thickness in mm Glue rate Surface point gluing in mm ² PERFORMANCE RATES Thickness in mm Glue rate Surface point gluing in mm ² PERFORMANCE RATES Grid Silionne 68 tex Chain and weft, EVA glue 68 0.2 0.15 0.16 8 0.1 0.14 0.5 53 Grid PES (polyester) 80 dtex Chain and weft, EVA glue 8 0096 0.38 0.02 7 0063 0.31 0.09 58 Grid PES (polyester) 1100 dtex Chain and weft, EVA glue 110 0.24 0.28 1.23 17 0175 0.11 2.6 123 Grid PES (polyester) 1100 dtex Chain and weft, PVC impregnation 110 0265 0.42 2.45 20 0.17 0.31 3.5 60 Grid Silionne 34 tex Chain and weft, EVA glue 34 0.15 0.22 0085 8 0.08 0.14 0.17 45 Grid PES (polyester) 80 dtex Chain and weft, PVC impregnation 8 0.1 0.53 0028 7 0.06 0.33 0.09 57

The six exemplary embodiments illustrated in Table 1 mention grids made from identical warp and weft threads and of identical title, it being understood that for the purposes of the invention, the warp and weft of the same grid can be made with son of different nature and different title without departing from the scope of the invention. In such a case, the performance ratio of the textile grid according to the invention is then calculated by taking the statistical average of the warp and weft threads.

It thus appears that the textile grids of the prior art, in comparison with the textile grid according to the invention, have reduced areas of gluing points, a higher glue ratio and a thickness also greater.

In particular, the level of glue of the textile grid according to the invention is less than 0.35.

In general, prior art grids made with warp and weft yarns composed of 68 tex glass yarns with an EVA (ethylvinylacetate) thermoplastic binder (glue content 20 to 30%) exhibited a mechanical strength at break less than 0.55N, while the breaking strength of grids of the same composition in accordance with the invention, with an adhesive ratio reduced to about 12 to 15% was close to 0.95N.

The textile grid according to the invention allows the use of glass threads whose title warp and weft son is between 5.5 gr / km and 136 gr / km, while obtaining the advantageous effects of the invention.

The measurement method used to calculate the area of the bonding point expressed in square millimeters was performed by measuring the overlap area of the warp 1 on the weft yarn and taking the average value from ten measuring points .

The method used to determine the linear density or the yarn count is in accordance with standard NF G07-317 (ISO 2060 of 06/95) for yarns other than glass and carbon. For glass and carbon yarns, the method for determining the linear density, expressed in gr / km, was carried out according to the T25-020 standard (ISO 1889 of 08/97).

The thickness of the grid was measured according to standard NF G37-102.

The glue ratio between 0 and 1 is expressed by the relation: $$\mathrm{Glue\; rate}=1-\frac{\mathrm{the\; mass\; of\; the\; wires\; on\; a\; square\; meter}}{\mathrm{the\; mass\; of\; the\; grid\; in\; g\; on\; a\; square\; meter}}$$

Such a measurement is made on the basis of the NF T57-511 standard.

According to the invention, the method of manufacturing a textile grid according to the invention and as described above, implements a series of conventional realization steps well known to those skilled in the art using conventional parameters. manufacturing methods adapted to the nature and the title of the weft and warp threads used, and the nature and the rate of glue used.

Thus, the manufacturing method implements a general step of construction of the son network, followed by a step impregnation and determination of the appropriate level of glue, then by a drying step of the grid obtained.

Devices for the production of such articles are described in numerous patents and in particular in French patents FR-1391900 and FR-2067607 . These devices essentially comprise a rotating element, commonly called fin, which distributes one or more weft son around two rotating wire support elements, spaced apart from each other so as to form between these elements a series of spaced loops which form a web of frames. In these devices, the shaft supporting the fin is hollow and at least one of the weft son is brought to the fin by passing inside said shaft. The rotation of the support elements laterally advances the web of frames, the wire loops forming this sheet remaining parallel to each other. This moving web of webs is then bonded together with one or more webs of warp threads which are brought into coplanar relationship adjacent to it by means of appropriate guides.

• on réalise un réseau de fils croisés ou superposés non tissés comprenant au moins deux nappes de fils de chaîne entre lesquels est interposée au moins une nappe de fils de trame,
• on imprègne le réseau de fils d'un liant pour assurer la liaison des fils de trame et de chaîne entre eux au niveau de leurs points de croisement.

Thus, the method of manufacturing a textile grid according to the invention is a method in which:

• a network of crossed or non-woven nonwoven threads comprising at least two sheets of warp threads between which is interposed at least one sheet of weft threads,
• the son network is impregnated with a binder to ensure the connection of the weft and warp threads to each other at their crossing points.

The peculiarity of the manufacturing method according to the invention lies in the fact of ensuring the pressing of the warp and weft yarn network before the drying phase of the binder is finished, the glue being still in a substantially or completely liquid or fluid.

Advantageously, the pressing of the son network is carried out at least partly simultaneously with the drying phase of the binder.

The manufacturing process can be carried out industrially continuously using conventional elements involving reels, pressing elements and drying elements including a series of cylinders.

The textile grid according to the invention can be used as such in the various conventional applications as mentioned above, namely as reinforcing or stabilizing elements. In addition, the textile grid according to the invention can also be used and incorporated into another element to form an industrial product incorporating the textile grid according to the invention.

In particular, the textile grid according to the invention can be glued or glued on a woven or non-woven element, such as a veil, to form a so-called complex industrial product. In such an embodiment, the structural characteristics to be taken into account for producing the grid will be identical to those of simple grids, the thickness E of the complex grid being that of the grid itself, equal to the thickness of that of the grid itself. of the complex minus that of the nonwoven element.

Claims (12)

1. Textile mesh formed by an array of nonwoven crossed yarns, which comprises at least two plies of warp yarns between which at least one ply of weft yarns is interposed, the warp and weft yarns being linked together at their intersections by a binder, creating a series of bonding points, characterized by a performance factor (TP) greater than 30, the performance factor being calculated using the formula: $$\mathit{TP}\mathit{=}\frac{\mathit{S}}{\mathit{T}\mathit{\times }E\mathit{\times }C}\times \mathrm{100}$$

   

   
   in which:

   S = area of the bonding points in mm² ;

   T = linear density of the warp and weft yarns in g/km;

   E = average thickness of the mesh in mm; and

   C = adhesive content between 0 and 1 and adhesive content being equal to: $$\mathrm{adhesive\; content}=1-\frac{\mathit{mass\; of\; the\; yarns\; persquare\; metre}}{\mathit{mass\; of\; the\; meshing\; per\; square\; metre}}\mathrm{.}$$

   
2. Textile mesh according to Claim 1, characterized in that the performance factor is between 45 and 120.
3. Textile mesh according to either of the preceding claims, characterized in that the thickness (E) is approximately uniform over the entire surface of the mesh.
4. Textile mesh according to Claim 3, characterized in that the thickness (E) is less than 0.175 mm and preferably less than 0.150 mm.
5. Textile mesh according to Claim 4, characterized in that the thickness (E) is between 0.150 mm and 0.06 mm.
6. Textile mesh according to one of Claims 1 to 5, characterized in that the adhesive content is less than 0.35.
7. Textile mesh according to one of Claims 1 to 6, characterized in that, for glass yarns, the linear density of the warp and weft yarns is between 5.5 g/km and 136 g/km.
8. Textile mesh according to one of Claims 1 to 7, characterized in that the binder is a thermoplastic adhesive.
9. Textile mesh according to one of Claims 1 to 8, characterized in that it is bonded to a woven or nonwoven product.
10. Complex industrial product incorporating the textile mesh according to one of Claims 1 to 9.
11. Process for manufacturing a textile mesh according to one of Claims 1 to 9, in which:

    - an array of nonwoven crossed yarns comprising at least two plies of warp yarns, between which at least one ply of weft yarns is interposed, is produced; and

    - the array of yarns is impregnated with a binder so as to ensure that the weft and warp yarns are linked together at their points of intersection,

    characterized in that a pressing operation is carried out on the array of yarns before the phase of drying the binder has been completed.
12. Process according to Claim 11, characterized in that the pressing of the array of yarns is carried out at least partly at the same time as the phase of drying the binder.

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