Dry strength composition, its use and method for making of paper, board or the like

Abstract

The invention relates to an aqueous dry strength composition suitable for use in manufacture of paper, board or the like. The composition includes a mixture of a synthetic polymer component, which is a copolymer of acrylamide and at least one anionic monomer, and a cationic starch component. The polymer component has an anionicity of 1-60 mol-%. The synthetic polymer component and cationic starch component provide the composition with a charge density in the range of 0.05-1 meq/g, when measured at pH 2.8, and 0.2-−3 meq/g, when measured at pH 7.0. The invention also relates to a method for making of paper, board or the like, where the dry strength composition is diluted with water, and the solution of the dry strength composition is added to the fibre stock before or after the addition of a cationic strength agent.

Dependencies are inferred from the claim text.