* * * * * DESCRIPTION The present invention refers to a synthetic textile support for bituminous roofing sheaths.

In roofing techniques the use of bituminous sheaths having a synthetic textile support is known. The synthetic textile support consists of two non- woven layers of polyester flock or continuous fibers. Between the two layers, reinforcing material of various kind that ranges from glass filaments to glass film, to polyester fiber film with discontinuous short filaments and so on is interposed.

In EP 0862667, in the name of the Applicant, a synthetic textile support is illustrated consisting of two layers of non-woven polyester fiber mat, between which a plurality of continuous reinforcing filaments, made of polyester filaments, is interposed that are arranged in parallel as regards one another, in the longitudinal direction of the textile support.

In this way a synthetic textile support is obtained, that solves both the problem of the transversal stretching of the product during the stage of impregnation with bitumen and the problem of assuring an adequate resistance of the bituminous sheath to the heat excursion that the sheath can undergo.

However a support thus made has as a limit the number of filaments that can be inserted between the two layers.

In fact, the number of filaments that can-be used cannot be higher than a certain quantity, since there are problems of physical space insufficiency for the extrusion heads of the same filaments.

In addition the insertion of the reinforcing filaments is a complication for the production process and the equipment being used.

In view of the state of the art described, scope of the present invention is to obviate to the problems of the known technique.

According to the present invention, such scope is attained by means of a synthetic textile support for bituminous sheaths, comprising a first and a second layer of continuous filament mat, characterised in that it additionally comprises between said first and second mat layers a third mat layer made of continuous filaments arranged in the longitudinal direction of said textile support.

Owing to the present invention it is possible to provide a fabrication process in which the three layers, making up as a whole the roofing sheath, are more integrated with each other.

Owing to the present invention it is possible to provide a process for the fabrication of the coating layers that is more resistant to heat stresses and traction stresses as compared with the processes of the known art.

Owing to the present invention a process for the fabrication of the coating layers is obtained that turns out to be simpler to be made as compared with the processes of the known art.

The characteristics and the advantages of the present invention will become evident from the following detailed description an embodiment thereof, that is illustrated as non limiting example in the enclosed drawings, in which: Figure 1 schematically shows an embodiment of the process for the production of the textile support according to the present invention; Figure 2 schematically shows the textile support in a plan view according to the present invention; Figure 3 shows the textile support in section along line III-III in Figure 2.

According to what schematised in Figure 1 a first layer 1 with continuous filaments 2 is manufactured by extrusion of a melt polyester polymer from a first series of extrusion heads A and placed on a conveyor belt 3.

With equal procedure a second layer 5 and a third layer 6, the latter with

continuous filaments 7 arranged in longitudinal direction, interposed between said first layer 1 and said second layer 5, are also obtained.

In particular the layer 5 is obtained by extrusion from the same melt polymer from a second series of extrusion heads B, as well as the layer 6 is obtained by extrusion of the same or different melt polymer from a third series of extrusion heads C.

In this way a multi-layer textile support 4 is obtained (shown in Figures 1 and 2), consisting of the superimposition of the three layers, respectively 1,6 and 5.

The textile support according to the invention is therefore made up of two layers 1 and 5 of continuous filament mat, between which a third layer 6 is interposed as a sandwich which is made of the same materials of the other two layers 1 and 5 or of different material, but in any case still as a continuous filament, this time arranged in the longitudinal direction.

In this way a multi-layer textile support is obtained that is more homogenous as compared with the known products, and that can be made with different characteristics and shapes as compared with the known ones.

In addition, with the interposition of said third layer 6 a greater filament density is obtained, so as to provide a resistance of the multi-layer support higher than what provided by the known art.

Finally a support thus made is obtainable with a simpler process and equipment as compared to what provided by the known art, because the series of heads A, B and C necessary for the creation of the multi-layer complex have the same technical characteristics.

The textile multi-layer support according to the present invention serves to the formation of supports for bituminous roofing sheaths