Precipitated Calcium Carbonates and Mineral Fillers for Construction Sealants
Sealants are used in many places in and around residential dwellings, as well as in the construction of office, factory and commercial buildings. For example, sealants fill joints between precast panels and between glass and steel in glass wall curtain buildings. They are also used in factory window glazing and the manufacture of insulating glass windows. In all applications, the ability of a sealant to flow under pressure, but behave near solid after the force is removed, is critical. This is typically called the rheology or shear thinning nature of the sealant products. This critical performance can be delivered by coated Ultrafine Precipitated Calcium Carbonates across the wide range of resin systems found in these products.
Precipitated Calcium Carbonates in Construction Sealants
Precipitated calcium carbonates (PCCs) are the preferred rheological additive and functional filler in higher-performance construction sealants. Building a true thixotropic, shear-thinning structure in the polymer, PCCs control yield value, sag, slump, and extrusion rates. They are often used as the sole thixotrope or to replace part of the more expensive conventional thickeners. In addition, the nano or ultrafine PCCs reinforce the polymer, increasing tensile strength and modulus.
Specialty Minerals PCCs for Construction Sealants
Specialty Minerals Inc. (SMI) manufactures a variety of nano and ultrafine PCCs for construction sealants. They are available for purchase worldwide in a variety of particle sizes and coatings to optimize performance in various resin systems and applications.
Other Minerals for Construction Sealants
SMI also produces ground calcium carbonates (GCCs) in the U.S Many construction sealants contain GCC as a cost-reducing filler. PCC and GCC work well in combination; their ratio can be changed to optimize the high-shear viscosity or extrusion rate of the sealant, physical properties of cured systems and total sealant cost. Barretts Minerals Inc. (BMI) produces talcs, which can improve the durability of sealants, especially those using shorter service life, water-based acrylic, vinyl-acrylic, vinyl acetate-ethylene or polyvinyl acetate emulsions via the platy, hydrophobic and chemically inert properties.