Method of adsorption of cationic and anionic polymers on the surface of particles and paper or nonwoven products containing such particles

The present invention provides a method of producing a particle or group of particles intended for use in making paper- and/or nonwoven products and having a coating of at least two, preferably at least three, thin layers of alternating cationic and anionic polymers located outside each other, in which the particle or group of particles is treated in consecutive steps with solutions of the alternating cationic and anionic polymers. The amount of the respective polymer to be added in each step is controlled by charge measurements of the treatment solution or a liquid containing the particles or group of particles and the polymer solution, after the treatment in each step in order to determine that substantially all polymer is adsorbed to the particle surface. The present invention also relates to a paper- or nonwoven product containing fibers and/or fillers produced according to a method of the invention. The present invention also encompasses paper products containing increased amounts of wet strength agent and tissue paper having improved wet strength.