Overtræksmateriale

Compositions adapted to form coating and impregnant films comprise an aqueous dispersion of (1) at least one water-insoluble addition polymer containing units of a vinyl ester, an acrylate or methacrylate ester, or a mono- or di-ethylenically unsaturated hydrocarbon, (2) at least one water-soluble ammonium salt of a copolymer of monoethylenically unsaturated monomers comprising an a ,b -ethylenically unsaturated carboxylic acid and having a molecular weight such that the viscosity of a 35% by weight aqueous solution of the copolymer salt, after standing for 1 week, is 5 to 100 c.p.s. at pH 6.5-7.5 and 25 DEG C., and (3) at least one anionic or nonionic surfactant, at least one of components (1) and (2) comprising at least 1/4 %, based on the weight of the respective component, of polymerized mers containing a ureido or thioureido group. Component (1) may be a homopolymer or copolymer of a vinyl ester of a C1- 18 aliphatic carboxylic acid, an ester of (meth)acrylic acid with a C1- 18 alcohol, or an unsaturated hydrocarbon such as ethylene, propylene, isobutylene, styrene, vinyl toluene, a -methyl styrene, butadiene or isoprene. Copolymers of mixtures of these compounds may be used; other suitable comonomers include vinyl or vinylidene chloride, chlorotrifluoroethylene, tetrafluoroethylene, vinyl ethers and thioethers, nitriles and amides of acrylic or methacrylic acid, and acrylic, methacrylic, itaconic, aconitic, citraconic, crotonic, maleic, fumaric and methacrylic dimer acids. Long lists of monomers, from which the (thio)-ureido mers are derived, are listed; preferred compounds contain a cyclic N,N1-ethylene-, N,N1 - methylethylene - or N,N1 - propylene - (thio)ureido group. Component (2) may be derived from an unsaturated carboxylic acid as exemplified above. Suitable anionic surfactants include alkali metal and ammonium salts of fatty alcohol sulphates, sulphates or sulphonates of polyethoxy-phenols, and dialkyl sulphodicarboxylates. Suitable nonionic surfactants include polyethoxyphenols and -bisphenols, polyethoxy mercaptans, polyethoxy fatty acids, polyethoxy fatty alcohols and polyethoxy etherified or esterified polyhydroxy compounds. When used as paints, the composition may include an organic or inorganic pigment, e.g. oxides, sulphides, silicates &c. of titanium, lead, zinc, antimony, zirconium, barium, calcium and magnesium, and an extender such as calcium carbonate, whiting, talc, barytes, magnesium and aluminium silicates, diatomaceous earth,