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: 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: For use in a process for producing a multi-layer coating upon a substrate surface, in which there is first applied to the surface a pigmented basecoat composition and there is then applied to the basecoat film a transparent topcoat composition, a pigmented basecoat composition which is based upon a dispersion in an aqueous medium of crosslinked polymer microparticles which have a diameter of 0.01-10 microns, are insoluble in the aqueous medium and are stable towards gross flocculation, the dispersion having a pseudoplastic or thixotropic character.

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.

Abstract: A process is described for making sterically stabilized non-aqueous dispersions of composite polymer microparticles, in which (1) monomers including at least one crosslinking monomer are polymerized in an aqueous medium at a temperature at least 10.degree. higher than the glass transition temperature of the polymer to be formed, in the presence of a block or graft copolymer stabilizing agent, under conditions such that there is at no time present a separate monomer phase, (2) further monomers, not including any crosslinking monomer, are polymerized in the dispersion thus obtained, the presence of a separate monomer phase again being avoided, and (3) the microparticles are transferred from the resulting dispersion into a non-aqueous medium which is a solvent for the non-crosslinked polymer generated in (2). The microparticles are of value for incorporation into coating compositions the main film-forming constituent of which is compatible with the non-crosslinked component of the particles.

Abstract: A process for producing a multi-layer coating upon a substrate surface, in which there is first applied to the surface a pigmented basecoat composition and then there is applied to the basecoat film a transparent topcoat composition; characterized in that the basecoat composition is based upon a dispersion in an aqueous medium of crosslinked polymer microparticles which have a diameter of 0.01-10 microns, are insoluble in the aqueous medium and are stable towards gross flocculation, the dispersion having a pseudoplastic or thixotropic character.

Abstract: Crosslinked addition polymer microparticles are produced by dispersion polymerization of monomers in an aliphatic hydrocarbon liquid in the presence of a dispersion stabilizer and also of a specified type of amino resin which is insoluble in the hydrocarbon liquid, at least one of the monomers polymerized carrying a group which can react with the amino resin under the conditions of polymerization. Coating compositions having improved application characteristics and/or giving improved film properties are obtained by dispersing the microparticles in combinations of suitable film-forming polymers and diluents.

Abstract: A process is described for making sterically stabilized non-aqueous dispersions of composite polymer microparticles, in which (1) monomers including at least one crosslinking monomer are polymerized in an aqueous medium at a temperature at least 10.degree. higher than the glass transition temperature of the polymer to be formed, in the presence of a block or graft copolymer stabilizing agent, under conditions such that there is at no time present a separate monomer phase, (2) further monomers, not including any crosslinking monomer, are polymerized in the dispersion thus obtained, the presence of a separate monomer phase again being avoided, and (3) the microparticles are transferred from the resulting dispersion into a non-aqueous medium which is a solvent for the non-crosslinked polymer generated in (2). The microparticles are of value for incorporation into coating compositions the main film-forming constituent of which is compatible with the non-crosslinked component of the particles.

Abstract: Improved application characteristics of spray-applied coatings, particularly for automobile bodies, are obtained when the composition applied comprises (A) a film-forming polyester or alkyd resin, (B) a volatile liquid solvent for the resin and (C) polymer microparticles which are stably dispersed in the solution of the resin in the solvent.Improvements observed include increased resistance to "sagging.

Abstract: A process for coating a substrate, especially an automobile body, by spray application whereby improved resistance to "sagging" or "running" on application can be obtained without reduction of the thickness of film which is applied; the process is characterized by the use of a coating composition comprising a film-forming acrylic resin, a volatile organic liquid diluent, a pigment other than a metallic flake pigment, and specified polymer microparticles which are stably dispersed in the combination of the resin and the diluent.

Abstract: A multilayer coating is produced by applying to a substrate as a base-coat composition a pigmented solution in a volatile organic liquid of a film-forming polymer, the solution also containing specified polymer microparticles, forming a polymer film from the base-coat composition, then applying to the film so obtained a transparent top-coat composition and finally forming a second polymer film upon the base-coat film.

Abstract: A method of preparing a stable dispersion in an aqueous medium of particles of polymer in which stabilisation of the particles against flocculation is effected by a steric mechanism. The method comprises (i) forming a sterically stabilized dispersion in a non-aqueous liquid of a first polymer insoluble in the non-aqueous liquid and in water; (ii) polymerizing monomer in the same non-aqueous liquid in the presence of the particles of the first polymer and of a steric stabilizer, so as to form a second polymer which is soluble in the chosen aqueous medium; (iii) transferring the resulting particles to the aqueous medium. There may be prepared in this way aqueous dispersions of polymers incorporating units of water-soluble monomers, which are diffiult to make by known aqueous emulsion polymerization techniques.

Abstract: Coating composition for spray application to a substrate comprising a film-forming polymer, a volatile organic liquid diluent, specified polymer microparticles stably dispersed in the combination of the film-forming polymer and the diluent, and metallic pigmentation also dispersed in the said combination. The composition affords improved control of the orientation of the metallic pigment.