Abstract: A process for preparation of a polymer product comprising the steps of i) feeding an aqueous mixture comprising a monoethylenically unsaturated monomer or a mixture of monoethylenically unsaturated monomers into a first reactor device (2) through at least one inlet; ii) partially polymerising the monomer or monomers and transferring the polymerising monomer or mixture of monomers from the inlet to an outlet (3) of the first reactor device (2) to provide a partially polymerised product; iii) flowing the partially polymerised product out of the outlet (3), in which no more than 60% of the monomer or mixture of monomers has been polymerised in the partially polymerised product as it exits the outlet (3) of first reactor device (2), and transferring it to a further reactor device (5), in which the further reactor device (5) has an inlet and an outlet (6); iv) continuing the polymerisation in the further reactor device (5) and removing the polymer product from the outlet (6) of the further reactor device (5), char