Abstract: The invention discloses a composite material 1 comprising essentially a mixture of hydroexpandable powder and thermobonding powder, sandwiched between two flat solid supports, one at least of which is at least partially hydrosoluble.This material can be used in agriculture, medicine, surgery, in the hygiene field and in the cable, particularly electric cable, industry. In this application, when water penetrates into the cable, the at least partially hydrosoluble support or supports release the hydroexpandable powder which rapidly forms a pad preventing propagation of the water through the cable.

Abstract: The invention relates to a hydroexpansible composite material, the method of preparing same and a composition for implementing this method, as well as to the uses thereof. The composite material includes a solid flat support having, on at least one of its faces, a coating with a high proportion of a hydroexpansible polymer powder fixed to the support by means of a hydrosoluble binder, the coating being essentially formed of:95 to 55% by weight of hydroexpansible polymer powder;5 to 23% by weight of hydrosoluble binder; and0 to 22% by weight of surfactant.This hydroexpansible material may advantageously be used in medicine, surgery agriculture and especially as sealing agent in cables, particularly electric cables.FIG. 2 shows how, in a cable, this material (11, 13) forms a sealing ring (13) about the point of infiltration of the water, thus preventing its longitudinal propagation.