Abstract: The present invention relates to method of forming a transparent and gas-permeability decreasing coating by virtue of applying a coating containing at least one polymer dispersion on a sheet of paper, board or similar cellulosic fiber based web in at least one coating step. The method according to the invention is based on the use of a polymer dispersion containing extremely pure talc particles having a degree of purity of 90-100% and a particle size of 90% smaller than 40 &mgr;m.

Abstract: The invention relates to coated board, a process for its manufacture, and containers and packaging formed therefrom. The board comprises at least one polymer-based coat preventing the transmission of liquids and gases, which coat is according to the invention made from a polymer dispersion to which talc particles are added so that talc will constitute 30-80% of the dry weight of the dried coat. The coating is applied onto the board during its manufacture as on-line coating. The board may be, for example, a multi-layer board (2) which has a middle layer (6) containing CTMP or other similar mechanical pulp, on its both sides outer layers (7) formed from sulfate pulp, against these on both sides of the board (2) talc-containing polymeric barrier layers (3), and on one side of the board a heat sealing layer (9) introduced onto the barrier layer (3).