Coating bituminous substrates

摘要

The quality of a mastic coating system for bituminous substrates is improved through the use of a topcoat composition and/or tiecoat composition comprising a water-insoluble latex polymer. The latex polymer has a Tg of from -25 DEG C to 20 DEG C and is prepared from a monomer mixture comprising: (a) at least 20 % by weight of at least one hydrophobic monomer selected from the group consisting of (C8 to C24) alkyl (meth)acrylates; (b) 0 or up to 45% by weight of at least one vinyl aromatic monomer; wherein the weight of (a) and (b) together constitute at least 25% by weight of said monomer mix (c) 0 or up to 75% by weight of at least one monomer selected from the group consisting (C1 to C4) alkyl (meth) acrylates; and (d) 0 or up to 5% by weight of at least one monomer selected from acrylic or methacrylic acid; wherein when (b) is not present in the monomer mix the amount of (d) is in the range from 0 or up to less than 3% by weight.. The mastic coating system has increased adhesion and blistering resistance when the coating is exposed to ponded water and may have reduced bleedthrough of chemicals from the bituminous substrate.