Abstract: A method of sizing paper by applying a composition comprising an aqueous dispersion of polymeric particles of particle size up to 1 micron, preferably 80-200 nm, wherein the polymeric particles comprise a water insoluble polymer matrix, preferably formed from styrene and 2-ethylhexyl acrylate, characterized in that an oligomer formed from a monomer blend comprising, (a) (meth)acrylamide, and (b) organic mercaptan or an organic sulphone, preferably dodecyl mercaptan or dodecyl sulphone is located at the surface of the particles. Compositions where the oligomer further comprises an ethylenically unsaturated monomer comprising either a tertiary amine group or a quaternary ammonium group, preferably dimethylaminoethylmethacrylate are novel. Advantages of the composition when applied to the surface of paper, include improved water resistance, brightness and printability properties of the treated paper.

Abstract: Polymer particles comprising a hydrophobic organic matrix and located at the exterior free cationic groups and a further polymer which comprises free hydroxy groups. The particles are produced by an aqueous suspension polymerization process wherein the continuous aqueous phase contains a polymerization stabilizer and a dissolved vinyl addition cationic monomer. The polymerization stabilizer can be any suitable polymer that comprises free hydroxy groups. The process results in polymers of average particle size in the range 50 to 150 microns and reduced levels of undesired polymer emulsion or undersized particles. The particles are particularly useful for absorbing water insoluble active ingredients, such as insecticides, insect repellents, fragrances, pheromones for subsequent slow release. The cationic surface character of said polymer particles makes them especially useful for forming stable dispersions or slurries in active concentrates such as perfume bases or detergent concentrates.

Abstract: The invention provides an aqueous polymer dispersion in which the copolymer is formed from70 to 90% by weight alkyl methacrylate provided by 0 to 30% by weight C.sub.1-3 alkyl methacrylate and 50 to 90% by weight C.sub.4-12 alkyl methacrylate;5 to 20% by weight styrene or alkyl styrene;2 to 10% by weight water soluble ethylenically unsaturated monomer;0.5 to 4% polyethylenically unsaturated monomer; and0 to 4% carbonyl containing ethylenically unsaturated monomer. The dispersion of the invention is particularly suitable for incorporation into compositions for coating on wood.