EP0315553B2 - Multilayer textile composite made from fibre fleeces having different characteristics - Google Patents

Description

The present invention relates to a method for obtaining a new kind of materials made up of a multilayer textile complex made from usable fibrous webs either as is, or as coating media or reinforcements for reinforcing laminated articles based on resin, waterproof coating consisting of support embedded in a bitumen composition. .

It has been proposed for a long time to carry out multi-layer textile complexes based on non-tablecloths fibrous woven, having different characteristics, these complexes being possibly reinforced by a woven or non-woven core, or any other material, by example a layer of foam and this, for their confer optimal properties according to their applications.

Thus, for example, it has been envisaged to carry out non-woven / fabric complexes and / or combining tablecloths based on different materials, for example a polyester nonwoven and a glass fiber veil.

In all these complexes, the main problem which arises is that of the connection of the different layers textiles together. To date, the main proposals to achieve this connection consist in associating the different layers together by gluing (see US-A-4,539,250 and 4,491,617), by sewing-knitting (US-A-3 044 146) or by needling (see FR-A-2 562 472 corresponding to US Patent 4,576,858).

If bonding techniques allow to obtain complexes whose external faces may be based on materials with characteristics different, for example a face consisting essentially synthetic fibers (polyester, polyamide, etc.), the other side being made up of mineral fibers (glass for example), they have however as disadvantages, due to the presence adhesive, to cause problems when you want impregnate or coat the structure thus produced. So, for example, when you want to use a such complex material as reinforcement a waterproofing coating based on a composition of bitumen, the presence of glue entails risks of aqueous residues in the product, which are very often the origin of the formation of bubbles in the bitumen. Of more, the presence of glue gives the complex produced a certain stiffness or rigidity. Finally, despite progress facts in the field of adhesives, risks of delamination between the layers still remains.

In his French patent 2,562,472 (corresponding US Patent 4,576,858), the Applicant has proposed a new type of material that solves this problem of connection between the layers, and to obtain complex very homogeneous without adding binding materials. According to this document, the different layers of materials are intimately mixed with each other and linked mechanically between them, the connection between the different layers being obtained by needling. This solution allows to realize multilayer complexes various such as for example complexes made up of glass fibers and polyester fibers, optionally combined with additional reinforcing elements, such as in particular non-woven grids. However, it was found that the action of the needles during the association of fibrous layers and more particularly in the event that additional reinforcements (grids woven or not, foam sheets ...) were associated to the said tablecloths, that there could be a deterioration said reinforcements. Furthermore, according to the teachings of this patent, the needling operation makes it possible to implant the fibers of the tablecloths, in particular fibers of glass, across the entire thickness of the other layer for example of a polyester nonwoven, such so that the fibers of the first layer on which the action of the needles protrudes on each side the other layer which therefore serves as a support. Consequently, in the completed complex, the external faces are both made from fibers of the same kind.

We have found, and this is what is the subject of the present invention, a method which allows to obtain a new type of material that like that described in the aforementioned patent, is based on fibrous sheets having different characteristics, said plies being linked together by entanglement fibers from one of the layers through the second which, by appropriate selection, tablecloths fibers that we assemble as well as by the choice of a entanglement technique known elsewhere, implementation works under very specific conditions, namely the technique of "needling" using not needles but to the action of jets of fluid under pressure (air or water) which not only keeps the characteristics (resistance, good connection of the layers between them without adding glue.) of the articles obtained according to the aforementioned patent, but also has the peculiarity of presenting external surfaces which are, if not entirely, but at least in majority, made from fibers of one and the same nature, each side retaining specific properties fibers from each of the original tablecloths entering in the realization of the complex.

• l'une des nappes entrant dans sa composition est à base de fibres discontinues synthétiques, souples, non cassantes, telles que des fibres de polyester, polyamide, polypropylène ..
• l'autre nappe est à base de fibres discontinues minérales relativement raides et cassantes (telles que verre, amiante..) ;
• une partie minoritaire des fibres discontinues synthétiques sont implantées dans l'épaisseur de la nappe à base de fibres discontinues minérales et ce, sans ressortir en surface de cette dernière.

The multilayer textile complex obtained by implementing the method according to the invention is characterized in that:

• one of the sheets used in its composition is based on synthetic staple fibers, flexible, non-brittle, such as polyester, polyamide, polypropylene fibers.
• the other layer is based on relatively stiff and brittle mineral staple fibers (such as glass, asbestos, etc.);
• a minority part of the synthetic staple fibers are implanted in the thickness of the sheet based on mineral staple fibers and this does not emerge on the surface of the latter.

In other words, in the material conforming to the invention, the fibers which provide the connection between the different layers are synthetic fibers re-oriented in the thickness direction of the complex multilayer, re-orientation being carried out in such a way so that it crosses the entire stack formed without however coming out on the outside of the layer to base of mineral fibers, so as not to alter the surface properties of the latter. At most, the ends of the synthetic fibers thus implanted will come to bloom on the surface of the tablecloth based on mineral fibers.

If the material according to the invention can be consisting only of non-fibrous structures woven, of course, we could associate a weave internal reinforcement, such as a textile grid woven or non-woven, a sheet of foam, a felt, film or any combination of these.

The method according to the invention allowing obtaining such a complex, consists of superimposing at least two nonwoven fibrous webs, dry (carding in particular), one of these sheets being made up of staple fibers soft synthetics, not brittle, the other of staple fibers relatively mineral rigid and brittle, and it is characterized by the fact that the stack is subjected of tablecloths thus produced by the action of jets of fluids (air or water) acting on superimposed materials on the surface of the web based on synthetic fibers, so as to re-orient part of the fibers in the thickness direction, the stack being, during the action of the jets, supported by a continuous surface, permeable, preventing synthetic fibers from coming out outside the surface of the base web mineral fibers.

In accordance with the process according to the invention, it is possible to interpose between the two fibrous layers aforementioned any additional element, such as for example a textile grid (woven or not), a fabric, a knitted fabric, a sheet of foam .., these elements being interposed alone or in combination with each other depending desired results and all layers being interconnected by synthetic fibers re-oriented in the thickness direction. It is obvious that these additional layers must be able to be crossed by the fluid jets.

Furthermore, according to one form of implementation of the process according to the invention, form according to which we use as water jets, water jets, it is advantageous before submitting the overlapping materials to the action of said jets, to compress them, to preferably by moistening them so that the operation is achieved by having a stack having the most thin possible compared to the number of layers used in its composition.

The new materials according to the invention have many advantages over to previous multilayer materials, by the fact that flexible synthetic fibers (polyester for example) that penetrate through the fiber-based web stiff (glass), allow to obtain a material unique composite of low thickness and devoid of any addition of glue, allowing many uses such as for example strengthening roofing membranes, laminated structures resin base ..

Furthermore, such a connection between the layers avoids any risk of delamination, the fibrous hooks obtained by the penetration of the jets on the veil in synthetic fibers through the veil layer in mineral fibers, to obtain a composite glue-free laminate, facilitating the penetration of bitumen, resin ..

In addition, the absence of glue reduces the risk of aqueous residues in the product which very often are causing bubbles to form.

Furthermore, the mineral fibers (glass) being arranged on one side of the complex, this allows to make finished products (for example coatings bituminous) meeting the specifications required for fire problems.

The realization of the complex thanks to the connection to means of Jets allows to obtain a product of a great flexibility, impracticable by a connection of different layers in a conventional way, at using an adhesive.

Finally, it was noted, in particular in the case where the tablecloth based on mineral fibers consists of glass fibers, that the fibers of this sheet which are closely linked to synthetic fiber (polyester), have advantageous strength properties at tensile strength, dimensional stability thermal, wear resistance, deterioration as it may be due to example with ultraviolet rays.

• la figure 1 est une vue schématique en perspective, montrant la structure générale du matériau conforme à l'invention et qui comporte dans ce mode de réalisation, une armature inteme additionnelle de renforcement ;
• la figure 2 illustre schématiquement, vu de côté, le processus opératoire d'obtention d'un tel matériau.

The invention, the advantages which it brings and the different applications that such a material can receive, will however be better understood thanks to the exemplary embodiments given below by way of indication but not limiting, and which are illustrated by the two accompanying figures. in which:

• Figure 1 is a schematic perspective view showing the general structure of the material according to the invention and which comprises in this embodiment, an additional internal reinforcement;
• FIG. 2 schematically illustrates, seen from the side, the operating process for obtaining such a material.

Figure 1 illustrates in general, in edgy perspective, the material structure according to the invention which consists of fibrous sheets (1, 2) having different characteristics, these plies being linked together by entanglement of fibers (3) from one of the layers (1) through the second (2).

According to the invention, one of the layers, (1) in this case is based on synthetic fibers flexible, not brittle while the other layer (2) is, for its part, based on mineral fibers relatively rigid and brittle, such as for example glass fibers, asbestos, carbon ..

In order to obtain a material according to the invention in which the outer faces (4, 5) of the complex retain the characteristics of fibrous webs (1, 2) of origin, the association of the layers between them is made so that it is fibers synthetic, flexible, which are brought to penetrate inside the tablecloth based on mineral fibers. To do this, we use the entanglement technique or entanglement designated by technicians by the expression "hydraulic intermingling" and the principle of which is shown diagrammatically in FIG. 2 and which generally involves submitting the superimposition of fibrous layers on the action of jets fluid from nozzles (6). The overlapping tablecloths (1) and (2) are, in accordance with the invention, brought below the nozzles (6) by means of a conveyor belt (7) enabling them to be kept at flat during the intermingling operation. During this operation, the tablecloth on which is exercised directly the fluid jets is the sheet (1) made up of synthetic fibers while the web (2) is, as to her, held on the support mat (7). Thanks to a such mode of implementation, under the action of the jets of fluid from the nozzles (6), part (3) of the fibers of the web (2) is re-oriented to penetrate inside the ply (2), the end (8) of said fibers thus re-oriented coming at most to flower the lower surface (5) of the ply (2) which is in contact with the support mat (7).

By doing this, the upper surface (4) of the sheet (1) has small perforations which are practically invisible given the made of the orientation of the fibers and which are distributed chance, this upper surface being of course made entirely of synthetic fibers, the surface (5) tablecloth based on mineral fibers retaining its original properties, by example its fire-resistant characteristics in the case where the fibers of the sheet (2) are glass-based.

Of course, the properties will depend on the chosen material.

If the material according to the invention can be consisting only of fibrous sheets thus bound between them, it is however preferable, in particular to communicate to the complex of characteristics mechanical tensile strength both in the long way that in the cross direction, to incorporate between the two layers (1, 2) an additional reinforcement (9) constituted for example by a textile grid (woven or no), a fabric, a knit. based on a material that can be either identical to one of the materials constituting the tablecloths (1, 2) is different. Of course, the structure of this additional reinforcement must be such that the fibers (3) of the ply (1) which are re-oriented can cross it under the action of the jets of fluid (6).

Example 1 :

• pour la nappe fibreuse (1) à base de fibres synthétiques souples, un voile de polyester obtenu par cardage à partir de fibres de 6,6 Dtex, coupe 50 mm pesant 150 g/m2 et ayant une épaisseur moyenne de 5 mm;
• pour la nappe (2) à base de fibres minérales, un voile de fibres de verre ayant une longueur de 50 mm, un diamètre de 14 microns, pesant 75 g'm2 et ayant une épaisseur moyenne de 2 mm.

A material according to the invention is produced from the following two components:

• for the fibrous web (1) based on flexible synthetic fibers, a polyester veil obtained by carding from fibers of 6.6 Dtex, cut 50 mm weighing 150 g / m2 and having an average thickness of 5 mm;
• for the web (2) based on mineral fibers, a veil of glass fibers having a length of 50 mm, a diameter of 14 microns, weighing 75 gm 2 and having an average thickness of 2 mm.

These two layers (1,2) are superimposed and brought back on an installation of the type illustrated in FIG. 2, so that the tablecloth (1) is located opposite fluid jets (6). Before treatment with jets of fluid (6), the complex formed is preferably subjected to the action of means (10) (not shown in the figure 2) allowing it to be compressed and, in the case where the fluid jets are water jets, to moisten the tablecloths thus compressed.

The pressure of the fluid jets will vary in depending on the thickness of the number of overlapping layers, this pressure being generally understood between 30 and 150 bars and, in this case, around of 70 bars.

At the end of the installation, a complex consisting of two different fibrous layers perfectly bonded to each other and the fibers (3) of the tablecloth (1) which have been driven through the sheet (2) does not protrude relative to the surface (5) of this tablecloth.

Such a material can be used in many applications and in particular as support coating, for example to make a reinforcement of bitumen chappe.

Example 2 :

We repeat example 1 but interpose between the two layers (1, 2) a grid (9), based on glass (silione) with four wires and four wefts per centimeter, each thread having a title of 51 Tex. This grid weighs 50 g / m2.

After treatment in accordance with the invention, obtains a complex structure having exactly the configuration given in Figure 1 and in which one of the faces (4) is based on polyester fibers, the other face (5) being, for its part, based on glass fibers.

Such a material is particularly suitable for be used as a bitumen support allowing to realize a single layer waterproofing coating so to obtain a coating having excellent characteristics dimensional stability, resistance to static and dynamic punching.

The material described above can be easily stored and handled. Furthermore, the properties of each layer is preserved, which is particularly interesting when you want, for example get one side fire and the other side insulating. In addition, the intermingling operation causes obviously, channels inside the complex which promote the penetration of resins, bitumens, or any other material that we would like associate with such a complex.

So if in the example above, each of the tablecloths (1, 2) consisted of the same type of fibers, it could be envisaged to include in these tablecloths various additives or mix them with other fibers. For example, we could incorporate inside the web based on thermoplastic fibers, hot-melt fibers whose properties could be revealed later, fibers capable of curling or revealing other properties, allowing better cohesion (bimetallic fibers for example).

Claims (8)

1. A process making it possible to obtain a multilayer textile complex which involves superposing at least two nonwoven fibrous fleeces (1,2) produced by dry means, one of these fleeces (1) being composed of non-brittle flexible discontinuous synthetic fibers and the other (2) of relatively rigid and brittle discontinuous mineral fibers, characterized in that the stack of fleeces(1,2) so produced is subject to the action of jets of fluid (6) acting on the superposed materials on the surface (4) of the fleece (1) based on synthetic fibers, so as to reorient some of the fibers (3) in the direction of thickness, during the action of the jets (6) the stack being supported by a permeable continuous surface (7), preventing the synthetic fibers (3) from protruding outside the surface (8) of the fleece (2) based on mineral fibers.
2. A process as claimed in claim 1, characterized in that the stack of fleeces is compressed before the action of the jets of fluid and is subjected to this action, at the same time being maintained in this compressed state.
3. A process as claimed in claim 2, characterized in that the jets of fluid are liquid jets, the compressed fleeces also being moistened before the action of the said jet.
4. A process as claimed in one of claims 1 to 3, characterized in that between the abovementioned fibrous fleeces (1,2) is interposed an additional reinforcing element (textile net, knit, foam, etc.), all the layers being connected to one another by means of the synthetic fibers (3) reoriented in the direction of the thickness.
5. A multilayer textile obtained by using the process as claimed in one of claims 1 to 4, said omplex being based on fibrous fleeces (1,2) having different characteristics, the said fleeces being connected to one another as a result of the interlacing of the fibers of one of the fleeces (1) with those of the second fleece (2), characterized in that :

   one of the fleeces (1) involved in its composition is based on non-brittle flexible synthetic fibers, such as discontinuous fibers of polyester, polyamide, polypropylene, etc. ;

   the other fleece (2) is based on relatively rigid and brittle discontinuous mineral fibers (such as glass, asbestos, etc.);

   a minor proportion (3) of the discontinuous synthetic fibers is implanted in the thickness of the fleece (2) based on discontinuous mineral fibers, without protruding at the surface of the latter.
6. A multilayer complex as claimed in claim 5, characterized in that it possesses an inner reinforcing structure (9).
7. A complex as claimed in claim 6, characteriezed in that the inner reinforcing structure (9) is a (woven or nonwoven) textile net, a fabric, etc.
8. A complex as claimed in claim 6, characterized in that the reinforcing structure is a foam sheet or a felt.

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