Minerals found in plastics include talc and calcium carbonates. Specialty minerals found in plastics include precipitate calcium carbonate, antiblock talcs, reinforcing talcs and ground calcium carbonates.
Talc and calcium carbonates are most often found in plastic products. They provide functionalities such as faster molding cycles, dimensional stability, surface finish, sandability and thickening. Other functionalities of these minerals include added impact strength, increased resin performance and sound deadening. These minerals also help to make products more affordable by replacing more expensive resins.
Precipitate calcium carbonate are highly functional additives and provide impact strength in rigid systems. Calendared stock, thermoforming, siding, fencing and PVC resin are common uses for this mineral. Antiblock talcs are used in polyoelfin and film applications. Reinforcing talcs are ultra fine and fine talcs that are used in thermoplastic olefine, engineering resins for stiffness and reinforced polyoelfins. Ground calcium carbonates offer economy and resin extension.
The choice of which mineral to use in a plastic product depends upon which performance enhancements are desired. Ground calcium carbonate provides moderate dimensional stability and is a major filler. Precipitated calcium carbonate provides minor dimensional stability and stiffness, major impact strength and is a major filler. Talc provides major antiblocking, dimensional stability and stiffness, nucleation, filler and minor impact strength.