Silica sols and use of the sols

摘要

PCT No. PCT/SE93/00663 Sec. 371 Date Feb. 3, 1995 Sec. 102(e) Date Feb. 3, 1995 PCT Filed Aug. 11, 1993 PCT Pub. No. WO94/05596 PCT Pub. Date Mar. 17, 1994Silica sols with a high content of microgel and particles with a specific surface area within the range 300 to 700 m2/g, preferably 400 to 650 m2/g. The sols can be prepared by acidification or a water glass solution and alkalization at a certain dry content, alternatively to a certain pH. The sols are particularly suitable for use as additives in papermaking in combination with cationic polymers and especially in combination with cationic acrylamide based polymers.