Abstract: A polyisocyanate mixture which is emulsifiable in water comprising;(i) An isocyanate functional oligomer, which is the reaction product of;(a) a polyisocyanate having tertiary isocyanate groups, and(b) a hydrophilic polyether having a group which will react with tertiary isocyanate groups, and(ii) a polyisocyanate having tertiary isocyanate groups.The polyisocyanate mixtures can be used with suitable filmforming polymers to make aqueous coating compositions.

Abstract: An aqueous coating composition comprising a film-forming material, a metallic pigment, phosphate inhibitor being either an orthophosphoric acid or an organic acid ester of phosphoric acid containing a group of formula (I): ##STR1## a cationic salt of one or more of the following metals: sodium, potassium, magnesium, calcium, strontium, barium, vanadium, cobalt, nickel, copper, zinc or silver; and a water containing diluent.

Abstract: The tendency of metallic pigments, especially of aluminum flake pigments, to react with the aqueous medium of a water-born paint composition with the generation of gaseous material is prevented or reduced by incorporating in the composition an agent containing in the molecule at least one P--OH group, or a salt derivative thereof, which is obtained by reacting a compound containing the grouping --O--PO(OH.sub.2) with one or more epoxide group-containing compounds at least one of which also contains at least one aromatic or alicyclic group.

Abstract: The production is described of a dispersion of polymer microparticles, which may optionally be crosslinked, by dispersion polymerisation in aliphatic hydrocarbon liquid under specified conditions of a monomer mixture which comprises up to 50% of styrene or a substituted derivative thereof and up to 50% by weight of a derivative of maleic acid or fumaric acid which is soluble in the hydrocarbon liquid at the polymerization temperature. The microparticles have a size in the range 100-400 nm and a high refractive index, and are suitable for incorporation in coating compositions which are based on a film-forming polymer, such as a thermosetting acrylic resin or an alkyd resin, containing a significant proportion of aromatic residues, and which are intended to be used either unpigmented or when containing only light-absorbing pigments.