Calprec PR 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 is a ultrafine coated precipitated calcium carbonate. Its main properties are: high purity, very small particle size in the nanometric range with narrow crystal size distribution, and organic surface treatment. Rheology modifier filler in sealants. Ultrafine coated precipitated calcium carbonate. Used as rheology modifier filler in sealants. Possesses high purity, very small particle size in the nanometric range with narrow crystal size distribution, and organic surface treatment.