The invention relates to the use of mixed aromatic vinyl-1,3-diene polymers stabilized by a protective colloid and present in the form of aqueous polymer dispersions or polymer powders redispersible in water as adhesives for porous substrates. The polymer dispersions and the polymer powders are obtained by emulsion polymerization of a mixture containing a) between 20 and 80 % by weight of one or more aromatic vinyls, b) between 19.9 and 79.9 % by weight of one or more 1,3-dienes, c) between 0.1 and 15 % by weight of one or more comonomers from the group comprising N-methylolacrylamide, N-methylolmethacrylamide and the N-(alkoxymethyl)-acrylamides and N-(alkoxymethyl)-methacrylamides with a C1-C6-alkyl rest. The sum of the above percentages adds up to 100 % by weight. Emulsion polymerization is carried out in the presence of one or more protective colloids and without emulsifier and possibly followed by drying of the resulting aqueous polymer dispersion.