METHOD FOR PRODUCING PAPER, BOARD OR THE LIKE AND AGGLOMERATE

摘要

The invention relates to a method for producing paper, board or the like. In the method is obtained an aqueous filler dispersion, comprising particles of at least one first filler, the filler dispersion having a floc size distribution with original mean chord length value. The particles of the first mineral filler are brought into a contact with a cationic pre-treatment agent, which is capable of initiating flocculation of the filler particles in the dispersion, whereby a pre-treated filler dispersion comprising flocs, which comprise first mineral particles, is formed. The pre-treated filler dispersion is combined ed with a stock of fibres. The floc size distribution of the filler dispersion is changed with the pre-treatment agent, which is a natural and/or synthetic polymer, so that the mean chord length value increases at least with 2% from the original mean chord length value. The invention relates also to an agglomerate comprising at least one first mineral filler particle, a plurality of second mineral filler particles attached to at least one first filler particle by a pre-treatment agent, which is a natural and/or synthetic polymer. The average particle size by weight of the first mineral filler particles is 1.5-4.0 μm, the average particle size by weight of the second mineral filler particles is 0.5-2.4 μm, provided that the second mineral filler particles are smaller than the first mineral filler particles, and the mean chord length of the agglomerate is <40 μm.

主权项

1. Method for producing paper, board or the like, comprising
obtaining an aqueous mineral filler dispersion, comprising particles of at least one first mineral filler, the filler dispersion having a floc size distribution with an original mean chord length value, bringing a cationic pre-treatment agent, which is capable of initiating flocculation of the filler particles in the dispersion, into a contact with the particles of the first mineral filler, and forming a pre-treated filler dispersion comprising flocs, which comprise first mineral particles, combining the pre-treated filler dispersion with a stock of fibres,characterised in changing the floc size distribution of the filler dispersion with the pre-treatment agent, which is a natural and/or synthetic polymer, so that the mean chord length value increases at least with 2% from the original mean chord length value.