"** *** DESCRIPTION The present invention relates to a synthetic textile support for bituminous sheath, preferably for roof covering.

Current synthetic textile supports for bituminous sheath comprise a couple of non-woven polyester layers between which a plurality of polyester reinforcement parallel threads is interposed in the longitudinal direction of the textile support (US-6131351).

When said textile supports with polyester threads are dipped in the hot bitumen (impregnation step), an elongation of said support is possible with consequent transversal narrowing problems.

In view of the state of the art herein described, object of the present invention is to limit the above mentioned problems in a cheap way.

According to the present invention, said object is attained by means of a synthetic textile support comprising a couple of non-woven polyester layers, characterising in that an oriented polyester film is comprised between said couple of non-woven polyester layers.

"Oriented polyester"means a film composed by threads oriented in the longitudinal direction of the textile support.

The characteristics and the advantages of the present invention will be made evident by the following detailed description of an embodiment thereof, which is illustrated as non-limiting example in the enclosed drawings, in which: Fig. 1 is a plan view showing the synthetic textile support according to an embodiment of the present invention; Fig. 2 is a enlarged sectional view according to the line 11-11 of Fig. 1; Fig. 3 is a enlarged sectional view according to the line III-III of Fig. 1 Figures show a synthetic textile support 1 provided of a couple of non-

woven polyester layers 2 between which an oriented polyester film layer 3 is comprised.

Said polyester film 3 is bound between the layers by needling or by binders or by a thermal fusion.

Layers 2 can be of flock non-woven or continuous thread non-woven with an orientation which is as much isotropic as possible or little anisotropic (in longitudinal direction). For some uses very anisotropic material can however be provided.

When the polyester film 3 has been stuck to the layers 2, the support 1 is ready for bituminous impregnation treatment.

During this treatment the prevailing isotropy of the layers 2 and the presence of the intermediate polyester film 3 allow to limit the elongation of the support 1 and therefore to avoid an excessive transversal narrowing.

However, the good warm rigidity of the support 1 doesn't exclude a good elasticity at non excessive temperature, anyway much lower than ones during the bitumen impregnation step. If for example the support 1 is used for roof covering and so it is posed on the roof, said support can follow the dilatations caused by sunbeam irradiation.

Substantially the present invention allows to provide a support 1 that doesn't have excessive deformation during the work step and that allows to have very good elastic properties when it is posed.

Lower deformations therefore allow a greater dimensional precision of the product obtained and generally an increase of the mechanical properties.

In fact, distortions produce many tension areas where breaks are easier or other bad phenomenons for the use of the support 1 may occur.

Nevertheless the presence of the oriented polyester film 3 doesn't prevent the further presence of polyester reinforcement threads as in US- 6131351 or of glass reinforcement threads as in US-5118550.