What is wollastonite?
Wollastonite is a naturally occurring, calcium metasilicate (CaSiO3) mineral with a needle-like particle shape. It is usually white and can withstand temperatures up to 1540°C.
Wollastonite is formed when impure limestone or dolostone undergo high temperature and pressure changes sometimes in the presence of silica-bearing fluids as in skarns or contact metamorphic rocks.
- High brightness
- Low moisture and oil absorption
- Low water solubility
- Low volatile content
- High melting point
- Acicular crystal structure
- Relatively high hardness (4.5 on Mohs’ scale)
- Paint and Coatings
- Adhesives and Sealants
Paint and Coatings
Wollastonite allows formulators to improve the cohesive strength of their coatings to obtain better corrosion and barrier properties, extend in-can stability and improve thermal stability at high temperatures. It has a low binder demand, low viscosity build and can easily be incorporated into both waterborne and solvent borne systems.
Wollastonite’s reinforcing properties, thermal stability, low resin demand and chemical purity make it an ideal reinforcement in thermoplastics, engineering alloys, thermosets and elastomers. Wollastonite also improves knit/weld line strength, prevents splaying during injection molding, and provides enhanced fire resistance characteristics in compounds.
Wollastonite is used to improve physical properties in gaskets, belts, plugs, O-rings, seals and molded parts.
- Wollastonite is an excellent lightweight reinforcing filler for cement boards, fiber-cement boards and fire resistant insulating boards.
- It brings a number of benefits in fiber-reinforced concrete.
Adhesives and Sealants
Wollastonite is a highly effective functional filler in adhesive and sealant applications, including structural, high temperature, pressure sensitive, hot melt, heat activated and UV curable adhesives and sealants.
- Due to its chemical composition, wollastonite acts as a natural frit, has a low loss on ignition and lowers CO2 emissions.
- It is a used as a cost-effective reinforcement for advanced ceramics, whitewares and structural clay bodies.