Aqueous dispersion which comprises hydrophobized silicon dioxide particles and in each case one or more dispersing additives, a basic composition, and which is free of colour pigments, inactive fillers and binders, in which the hydrophobized silicon dioxide particles have a methanol wettability of 30 to 60 and are present in the dispersion with a proportion of 0.1 to 50% by weight,—the proportion of water is 30 to 90% by weight based on the dispersion,—the dispersing additive is at least one phosphate ester of an ethoxylated alcohol having 8 to 18 carbon atoms, the proportion of which is 3 to 25% by weight based on the proportion of the hydrophobized silicon dioxide particles,—the basic composition comprises or consists of one or more amines of the general formula RNH2, R2NH and R3N, where R is an alkyl group or a hydroxyl-substituted alkyl group having in each case 2 to 10 carbon atoms, and is present with a proportion of 5 to 30% by weight based on the proportion of hydrophobized silicon dioxide particles,—the dispersion further comprises one or more polyols having 2 to 15 carbon atoms, the proportion of which is 1 to 10% by weight based on the proportion of hydrophobized silicon dioxide particles,—the pH of the dispersion being 9 to 11.