Calprec PR-250 Coated Precipitated Calcium Carbonate Cales de Llierca Extenders / Fillers >> Calcium Carbonate, precipitated Rheology Modifiers / Thickeners >> Mineral >> Precipitated calcium cabonate Acid Absorber / Acceptor SEALANT Calprec PR-250 is a ultrafine coated precipitated calcium carbonate. Its main properties are: high purity, narrow crystal size distribution in the nanometric range, and organic surface treatment. High rheological performance. Rheology modifier filler in sealants. Ultrafine coated precipitated calcium carbonate. Used as rheology modifier filler in sealants. Possesses high purity, narrow crystal size distribution in the nanometric range, and organic surface treatment. Has high rheological performance.