Polymer composition

Dry coating binder comprising a polymer which comprises at least 80% by weight of main monomers, wherein the polymer is a S/BA/AA copolymer, wherein the main monomers are styrene (S) and butyl acrylate (BA), and the additional monomer is acrylic acid (AA) or the polymer has main monomers being vinyl esters of carboxylic acids comprising up to 20 carbon atoms and hydrolyzed to alcohols, or the polymer is a mixture of these., and that the particle size of the binder is between 200-400 nm.

Method of improving the surface strength of coated paper, which comprises using a dry coating binder in a paper or board coating composition, wherein the paper coating composition is in powder form and is applied on the paper using dry coating technology, the binder comprising a polymer which comprises at least 80% by weight of main monomers, the main monomers being selected from C1-C20-alkyl (meth)acrylates, C1-C20-hydroxy alkyl (meth)acrylates, C1-C20-alkyl (meth)acrylamides, C1-C20-hydroxy alkyl (meth)acrylamides, vinyl esters of carboxylic acids comprising up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, ethylenically unsaturated nitriles, vinyl ethers of alcohols comprising 1 to 10 carbon atoms, aliphatic hydrocarbons having 2 to 8 carbon atoms and one or two double bonds or mixtures of these monomers, and that the particle size of the binder is between 200-400 nm.