Substrate impregnated with sprayed clay, and method for manufacturing same

A method for producing a clay-impregnated substrate, including steps in which:

• a pasty mixture is produced, containing a filler including essentially clay,
• the pasty mixture is sprayed toward a dry, flexible substrate having a fibrous structure,
• then said substrate provided with said mixture is dried, wherein, with a view to preventing the filler from becoming significantly separated from the dried substrate when it is then immersed in distilled water, at ambient temperature:
• the pasty mixture produced is made of phyllitic, non-swelling clay, representing between 30% and 60% by weight of the mixture,
• at least one of the following conditions is implemented:
• the pasty mixture is produced in a tank where an air pressure of between 1.5 and 7×105 Pa is established, and,
• the mixture is sprayed at a distance from the substrate of between 5 cm and 30 cm,
• said substrate toward which the mixture is sprayed is stretched out, and is a nonwoven material having at least one of natural and synthetic fibers obtained by an aerodynamic and dry process, in which the mixture that is sprayed is free of polymerization agent capable of causing polymerization in one of the mixture and the substrate provided with the sprayed mixture,
• said mixture is sprayed so as to impregnate the substrate with it,
• and, before being dried, the impregnated substrate is neither rolled between compression rollers nor scraped in order to further incorporate the mixture into the substrate.