Calofort SM Precipitated calcium carbonate Specialty Minerals Rheology Modifiers / Thickeners >> Mineral >> Precipitated calcium cabonate PU - Prepolymers Polyvinyl Chloride (PVC) SEALANT Calofort SM pcc is widely used in polyurethane sealants, mastics and PVC plastisols where slump resistance and viscosity control are important requirements. In a sealant or plastisol formulation, CALOFORT SM pcc can allow partial or total replacement of more expensive thixotropic aids. Precipitated calcium carbonate. Used in sealants, mastics and PVC plastisols. Provides slump resistance and viscosity control. Can allow partial or total replacement of more expensive thixotropic aids.