EP1111114A1 - 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 grids textiles formed of a network of warp and weft threads held in place by bonding at the crossover point of the wires, such grids intervening especially as reinforcements or supports in different applications industrial.

The present invention relates to a textile grid formed by a network of threads crossed or superimposed nonwoven comprising at least two plies of threads between which is interposed at least one layer of son weft, the warp and weft threads being linked together at their crossing with a binder creating a series of bonding points.

The present invention also relates to any finished or unfinished industrial product finish 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 superimposed threads is produced nonwoven comprising at least two plies of warp threads between which is interposed at least one ply of weft son, and coated the wire network of a binder to ensure the connection of the weft and chain between them.

It is already known to industrially produce grids formed from a network of nonwoven cross-threads, the threads being glued together at their crossover points by impregnation with a binder, such as glue thermoplastic or other. Known grids such as those illustrated by example in Figure 1, use at least two layers of son chain A, B, superimposed or even offset, each pair of plies A, B, having interposed therebetween at least one ply C of weft yarns. According to these known embodiments, the warp threads 1 and the weft threads 2 are linked between them at their crossing 3 by a binder 4 creating a series of points bonding in order to obtain a textile grid having a finished structure and mechanically stable.

The grids produced using this technique generally give satisfaction and serve as reinforcements or supports in very technical fields varied such as for example without limitation, in the industry building, as a support for parquet and ceramics or coverings wall and carpet, in the paper industry, or as as a reinforcing element in synthetic foams or the like.

Nevertheless, it appears that the textile grids known to date suffer a certain number of drawbacks and in particular a drawback linked to the relatively large and mainly very irregular thickness of the wire rack. Indeed, the method of manufacturing known grids implies a simple coating of a glue or thermoplastic binder, of the PVC or PVA type for example, without any additional operation. It follows that the textile grids obtained have a relatively large thickness whatever the nature, type, number of wires used leading to a relative lack of flexibility of the grid obtained. In addition, the thickness of the textile grids known to date is particularly irregular due to the existence of a relief at the crossing points of the chain wires 1 and grid 2. The presence of such irregularities in the grids textiles of the prior art obviously presents a number disadvantages on the industrial level, and particularly in certain specific applications.

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

Finally, the textile grids of the prior art appear to involve a relatively high consumption of adhesive or thermoplastic binder used, especially if you want to try to strengthen the hold mechanical network of wires at the crossing points. This leads to increasing the cost price of the products obtained, which constitutes an industrial disadvantage.

To try to at least partially remedy the drawbacks listed previously, it has already been envisaged, in particular in patent GB-1463969, to make a textile grid of reduced thickness in which the redistribution of the network of wires is obtained by compression, and in particular by calendering the grid in order to flatten it. The calendered grid obtained actually has a reduced thickness, for example of the order of 200 at 150 micrometers, in comparison with the 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 bonding points between the warp and weft threads, so that the general mechanical resistance to rupture of these points is greatly reduced compared to conventional grids. In addition, the technique of compression by calendering of the textile grid is not accompanied by reduction in the amount of glue used. In total, the textile grids calendered, in addition to the relative complexity and difficulty of obtaining the product on industrially, suffer from a number of disadvantages making their limited or even inappropriate use in certain applications.

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

Another object of the invention aims to propose a new textile grid having general performance characteristics particularly high in terms of mechanical strength, flexibility and size.

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

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

A complementary object of the invention aims to propose a new process manufacturing a textile grid formed by a network of crossed threads or particularly easy to make nonwoven overlays.

S = Surface des points de collage en mm²,

T = Titre des fils de trame et chaíne 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 crossed threads comprising at least two layers of warp threads between which is interposed at least one layer of weft threads, the warp and weft son being linked to each other at their crossings by a binder creating a series of bonding points, characterized by a performance rate (TP) greater than 30, the performance rate being calculated according to the formula: TP = S T x E x C x 100 in which :

S = area of bonding points in mm ² ,

T = Title of the 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 chaíne 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 chaíne 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 using a method of manufacturing a textile grid according to the invention in which:

• a network of crossed nonwoven threads is produced comprising at least two plies of warp threads between which at least one ply of weft threads is interposed,
• the network of wires is impregnated with a binder to ensure the connection of the weft and warp wires between them at their crossing points,

characterized in that the wire network is pressed 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 attached drawings below, purely by way of non-limiting illustration, in which:

• Figure 1 illustrates in a partial sectional view, a detail of the structure of a textile grid of the prior art.
• 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 FIG. 2, the textile grid according to the invention is formed by a network of crossed or superimposed nonwoven threads comprising at least two plies A, B, of warp threads 1 between which is interposed at least one ply C of weft son 2.

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

Without limitation, the textile grid according to the invention may be formed by a variable number of wires, which can vary for chain wires by 0.5 wire per centimeter to 8 threads per centimeter, and for weft threads can vary by example from 0.5 thread per centimeter to 5 threads per centimeter.

Without limitation, and as is well known to those skilled in the art, all type of textile thread commonly used to date in the production of grids textiles may be used, and for example threads of the Silionne, polyester type, cellulosic, aramids or polyamides.

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

Within the meaning of the invention, any binder or glue commonly used to date in the technical field considered may be used, and in particular any binder or thermoplastic adhesive. Without limitation, the connection and coating of the network son forming the textile grid according to the invention may be formed by synthetic latex (SBR ...), PVAC, plastisols, PVC, alcohol polyvinyl (PVA), conventional iron-on impregnations, polyurethane binders or acrylic binders for example.

According to the invention, it has become apparent that, having regard to the title of the wires weft and warp used, we maintained the structural characteristics of the network of threads of the textile grid according to the invention, such as the surface bonding points, as well as the average thickness of the grid and the rate of glue used or present in the mass of the wires, beyond a value minimum, or in a specific range, we obtained characteristics remarkable behavior of the textile grid.

S = Surface des points de collage en mm²,

T = Titre des fils de trame et chaíne 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 in accordance with the invention can thus be expressed by a TP performance rate greater than 30, the performance rate being calculated according to the formula: TP = S T x E x C x 100 in which :

S = area of bonding points in mm ² ,

T = Title of the 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 by example preferably less than 0.175 mm and regular without existence a notable relief at the crossing of the warp 1 and weft threads 2, while having excellent mechanical strength of the wire network with a at least 30% less glue consumption compared to classic textile grids.

Thus, at the crossings, the thickness of the grid is substantially equal to two times the thickness of the wire alone excluding crossing.

Incidentally, the textile grid obtained has good flexibility as well reduced footprint since, in comparison with textile grids known classics, the footage wound on the same reel perhaps doubled in the case of a textile grid according to the invention.

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

In the same way, according to the invention, the thickness E will be so preferably 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: Chain title + weft title 2

Table 1 below expresses in a comparative manner the measured values, characteristic of a fine grid in accordance with 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 wire networks.

The six exemplary embodiments illustrated in table 1 show grids made from identical warp and weft threads and also identical title, it being understood that within the meaning of the invention, the networks of warp and weft threads of the same grid can be made with threads of a different nature and of different title without as well go beyond the scope of the invention. In such a case, the rate of performance of the textile grid according to the invention is then calculated taking the statistical average of the titles of the warp and frame.

It appears as well as the textile grids of the prior art, in comparison with the textile grid according to the invention, have surfaces of reduced bonding points, higher adhesive ratio and thickness also superior.

In particular, the adhesive content of the textile grid according to the invention is less than 0.35.

In general, grids of the prior art produced with warp and weft yarn composed of 68 tex glass yarn with a binder thermoplastic EVA (ethylvinylacetate) (glue rate 20 to 30%) had a mechanical breaking strength of less than 0.55N, while the breaking strength of grids of the same composition according to the invention, with an adhesive content reduced to approximately 12 to 15 % was close to 0.95N.

The textile grid according to the invention allows the use of glass threads whose title of warp and weft threads 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 collage expressed in square millimeter was carried out by measuring the area covering the warp thread 1 on the weft thread and taking the average value from ten measurement points.

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

The thickness of the grid was measured in accordance with the standard NF G37-102.

The glue ratio between 0 and 1 is expressed by the relationship: Glue ratio = 1- the mass of the grid in g over one square meter the mass of the wires on a square meter.

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

According to the invention, the process for manufacturing a conforming textile grid to the invention and as described above, implements a series of conventional steps well known to those skilled in the art art using conventional manufacturing parameters adapted to the nature and under the weft and warp threads used, and the nature and at the rate of glue used.

This is how the manufacturing process implements a step general construction of the wire network, followed by a step impregnation and determining the appropriate rate of glue, then by a step of drying 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 include a rotating element, commonly called a fin, which distributes one or several weft threads around two rotating fi! s support elements, spaced from each other so as to form between these elements a series of spaced loops that form a web of wefts. In these devices, the shaft supporting the fin is hollow and at least one of the wires weft is brought to the fin by passage inside said shaft. The rotation of the support elements moves the sheet of material laterally wefts, the loops of wire forming this sheet remaining parallel between they. This sheet of moving wefts is then assembled by bonding with one or more layers of warp threads which are brought into adjacent coplanar relationship with 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 chaíne 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 chaíne entre eux au niveau de leurs points de croisement.

Thus, the process for manufacturing a textile grid according to the invention is a process in which:

• a network of crossed or superimposed nonwoven yarns is produced, comprising at least two plies of warp son between which is interposed at least one ply of weft son,
• we impregnate the network of wires with a binder to ensure the connection of the weft and warp wires between them at their crossing points.

The particularity of the manufacturing process according to the invention resides in ensuring the pressing of the network of chain wires and weft before the drying phase of the binder is finished, the glue still in a substantially or completely liquid state or fluid.

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

The manufacturing process can be carried out industrially by continuous 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 classic applications as mentioned previously, namely as reinforcements or stabilization. In addition, the textile grid according to the invention can also be used and incorporated into another element for form an industrial product incorporating the textile grid in accordance with the invention.

In particular, the textile grid according to the invention can be glued or laminated on a woven or non-woven element, such as a veil, to form an industrial product called complex. In such an embodiment, the structural characteristics to take into account for the realization of 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 that of the complex minus that of the nonwoven element.

Claims (12)

Textile grid formed by a network of nonwoven crossed threads comprising at least two plies of warp threads between which is interposed at least one ply of weft threads, the warp and weft threads being linked together at their crossings by a binder creating a series of bonding points, characterized by a performance rate (TP) greater than 30, the performance rate being calculated according to the formula: TP = S T x E x C x 100 in which : S = area of bonding points in mm ² , T = Title of the weft and warp threads in gr / km, E = Average thickness of the grid in mm, C = Glue ratio between 0 and 1. Textile grid according to claim 1 characterized in that the rate performance is between 45 and 120. Textile grid according to one of the preceding claims characterized in that the thickness (E) is substantially regular over the entire surface of the grid. Textile grid according to claim 3 characterized in that the thickness (E) is less than 0.175 mm, and preferably less than 0.150 mm. Textile grid according to claim 4, characterized in that the thickness (E) is between 0.150 mm and 0.06 mm. Textile grid according to one of Claims 1 to 5, characterized in that the adhesive content is less than 0.35. Textile grid according to one of Claims 1 to 6, characterized in that that for glass yarn, the title of the warp and weft threads will be between 5.5 gr / km and 136 gr / km. Textile grid according to one of Claims 1 to 7, characterized in that that the binder is a thermoplastic adhesive. Textile grid according to one of Claims 1 to 8, characterized in that whether it is glued to a woven or non-woven product. Complex industrial product incorporating the textile grid in accordance with one of claims 1 to 9. Method for manufacturing a textile grid according to one of Claims 1 to 9, in which: a network of crossed nonwoven threads is produced comprising at least two plies of warp threads between which at least one ply of weft threads is interposed, we impregnate the network of wires with a binder to ensure the connection of the weft and warp wires between them at their crossing points characterized in that the wire network is pressed before the drying phase of the binder is completed. Method according to claim 11 characterized in that the wire network pressing is carried out at least in part from simultaneously with the drying phase of the binder.

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