Pigment for sizing paper or board, contains particles comprising amorphous mixture of calcium carbonate and silica

摘要

The pigment particles comprise an amorphous mixture of calcium carbonate and silica. A pigment composition for sizing paper or board comprises an aqueous composition containing (A) calcium carbonate and (B) silica particles. The individual particles comprise a preferably entirely amorphous mixture of (A) and (B). Independent claims are also included for (a) an aqueous pigment composition for sizing paper or board, comprising particles of (A) and (B) prepared by reacting an alkali metal silicate solution containing calcium hydroxide particles with carbon dioxide, (b) a method for preparing the composition by reacting an alkali metal silicate solution containing calcium hydroxide particles with carbon dioxide, (c) paper or board provided with a sizing layer containing the composition, and (d) the use of the composition as a pigment for sizing paper or board.