Protecting materials subject to degradation by atmospheric and polluting agents by means of perfluoropolyethers

Claim 1

A process for protecting marble, stones, tiles and articles manufactured from such materials from the degrading action caused by atmospheric agents and pollutants, which comprises applying to the surfaces of said materials and manufactured articles a protective coating comprising, as essential protective agent, a fluid perfluoropolyether having at least one of the following general formulae: ##STR2## and A--O--(C.sub.2 F.sub.4 --O).sub.m --(CF.sub.2 O).sub.n --B (II) wherein p, q and r are integers, q and r may be equal to zero, the sum p+q+r is an integer from 5 to 250, m and n are integers, n may be equal to zero, the sum m+n is an integer from 10 to 1000, A and B are perfluoroalkyl radicals containing 1 to 3 carbon atoms, said fluid perfluoropolyether being applied as such or diluted with a solvent or mixture of solvents having a boiling temperature below 80° C.