Precipitated calcium carbonate pigment, especially for use in inkjet printing paper coatings

摘要

Novel and innovative PCC pigments, having a reduced production cost, able to be used in a paper coating formulations to manufacture coated high-quality matt papers, in particular for inkjet applications. Process for the preparation of same, using a reduced flow rate of a carbon dioxide-containing gas in the PCC carbonation step, which produces stable, porous, agglomerates of PCC featuring unique properties and structure, this step being followed by an upconcentration step to increase the solids content.

主权项

1. A process for preparing precipitated calcium carbonate (PCC) useful for ink jet printing applications comprising the steps of:
a) preparing a calcium hydroxide slurry by mixing quicklime (CaO) with water; b) screening the calcium hydroxide slurry obtained in step a) to obtain a screened slurry; c) adjusting the temperature of the screened slurry to obtain a temperature adjusted slurry; d) contacting the temperature adjusted slurry with a carbon dioxide-containing gas at a carbonation gas flow rate of below 30 liters per minute at standard temperature and pressure per kilogram calcium hydroxide in the presence of (i) magnesium sulphate and aluminium sulphate, (ii) magnesium sulphate and zinc sulphate, or (iii) magnesium sulphate, aluminium sulphate and zinc sulphate, to obtain agglomerates/aggregates; and e) screening the agglomerates/aggregates obtained in step d) to obtain ultrafine PCC agglomerates having a mean aggregate diameter of 1 to 5 μm, wherein the ultrafine PCC agglomerates comprise ultrafine calcium carbonate particles bound together.