PAPER STRENGTH ENHANCEMENT BY SILICATE/STARCH TREATMENT

摘要

Alkaline dry silicate compositions are disclosed for use as additives in conventional paper or board making to impart significantly improved strength to paper or paper board. The particle size and moisture content of dry alkaline silicate compositions according to the present invention are selected such that these compositions are sparingly soluble in water at temperature conditions encountered in the wet end of a paper or board making machine, but are rapidly soluble under the higher temperature conditions encountered in the drier section of such a machine. In consequence, there results effective penetration of the web of paper or board by the alkaline silicate composition and any selected additives thereto. One particularly useful additive is starch, particularly starch in the form of uncooked starch particles, which imparts a synergistic strengthening effect. In another aspect, the present invention is an improvement to the conventional process for preparing paper or board, comprising the step of adding compositions as aforesaid in particulate form to the aqueous slurry of cellulosic fibres prior to formation of a web of paper or board.