In unsaturated polyester applications, functional mineral fillers provide viscosity build and surface finish while reducing shrinkage and formulation costs. These applications include reinforced fiberglass showers, boats, and other products using laminated resins and gel coats. They are also used in auto-body fillers, sheet-molding compounds (SMC), and bulk-molding compounds (BMC). These versatile fillers are used in unsaturated polyester cast polymers or cultured marble for bathroom sinks and other building products. Click here for more information on cast polymer applications.
Specialty Minerals Precipitated Calcium Carbonates for Unsaturated Polyesters
Specialty Minerals Inc. (SMI) precipitated calcium carbonates (PCCs) offer the quickest viscosity build and the highest quality surface finish in unsaturated polyesters. These PCC products range from 0.07 micron nano ultrafines to 1.9 micron scalenohedrals and are typically uncoated. Coated versions of most PCC products are available.
- Calofort® U and Multifex-MM® PCCs are 0.07 micron uncoated nano ultrafine PCCs. These PCCs are used where best thixotropic rheology and sag control are desired in systems with more than 10-percent filler loading. They also give the best surface finish, so they are excellent in gel coats. Both are manufactured in SMI’s plant in Birmingham, U.K., and are sold as Multifex-MM® PCC in the U.S., and as Calofort® U PCC in the rest of the world.
- Albafil® PCC is a 0.7 micron uncoated superfine PCC manufactured in Adams, Massachusetts. It is ideally suited for applications requiring viscosity build and surface finish.
- Albacar® 8101, Albacar® 5970 and Calopake® 5970 PCCs are 1.4 and 1.9 micron scalenohedral PCCs with a starburst shape which gives high surface area and high-oil absorption. These PCCs are excellent for producing very thick mixtures and in filling automotive BMC (bulk molding compounds). The Albacar® PCCs are made in Adams, Massachusetts, and the Calopake® PCC in Birmingham, U.K.
Click on a product’s name to download the technical data sheet and click here to read more about SMI PCCs in plastics.
Specialty Minerals Ground Calcium Carbonates for Unsaturated Polyesters
Ground calcium carbonates (GCCs) are excellent cost-reducing fillers for all types of unsaturated polyester products. The smaller-sized grades give better surface finishes while the larger particles with their lower oil absorptions can be loaded to higher levels for better economy. The GCCs recommended for unsaturated polyesters are:
- Vicron® - East GCCs – are high-brightness GCCs with median particle sizes ranging from 3.5 to 10 microns. They are produced in Adams, Massachusetts.
- Vicron® - West GCCs – are high-brightness GCCs ranging in size from 2 to 10 microns. They are produced in Lucerne Valley, California.
Cast polymer/cultured marble applications tend to use coarser GCC or dolomite (calcium magnesium carbonate) fillers. Click here to read more about SMI products for cast polymers.
Click on a product’s name to download the technical data sheet for that product. To read more about SMI GCCs for plastics, click here.
Specialty Minerals Talcs for Unsaturated Polyesters
Talcs provide viscosity build while reducing shrinkage and formulation costs. SMI offers several grades of talc for this application. Two products, Gel Talc and Body Filler Talc, were developed for unsaturated polyester products, using high brightness Chinese talcs. The Talcron® and MicroTuff® talcs, also used in unsaturated polyesters, are produced from local ore in Barretts, Montana.
Talcs are also a major component of unsaturated polyester-based putties used as fillers in auto body repair. Talc improves the sandability of the cured putty and provides a smooth surface, as well as reducing cracking. It also adds viscosity to the product. Two different talcs sizes are generally used, a smaller one about 1.5 microns for viscosity and a larger one about 7 to 8 microns for sanding and filling.
SMI talcs for unsaturated polyesters include:
- Gel Talc – is a 4 to 6 micron talc with low oil absorption added to gel coat formulations to improve surface finish, control viscosity, improve opacity, and reduce shrinkage and costs. Addition rates can range up to 20 percent by weight. It is manufactured in SMI’s plant in Mount Vernon, Indiana.
- Body Filler Talc – is a 7 to 10 micron talc which allows optimum pigment-to-binder ratio, maximizes performance, and reduces cost. Its loading can be as high as 55 percent by weight. This talc also reduces shrinkage and cracking and improves sandability.
- Talcron® talcs – are the Montana talcs for unsaturated polyesters with median particle sizes ranging from 1 to 8 microns.
- MicroTuff® talcs – are Montana talcs similar to the Talcron® talcs but with lower oil absorptions, which allow higher filler loadings.
Download a product data sheet by clicking on the product name of interest. Click here to read more about SMI talcs in plastics.
- Specialty Minerals minerals products for plastics
- Ground calcium carbonate (GCC) in plastics uses
- Precipitated Calcium Carbonate (PCC) in plastics uses
- Talc in plastics uses
- What is Ground Calcium Carbonate (GCC)/Limestone? A mineral introductory webpage
- What is Precipitated Calcium Carbonate? A mineral introductory webpage
- What is Talc? A mineral introductory webpage
- SMI minerals Used in Automotive Parts
- Specialty Minerals Used in Housing and Construction Materials
- Download technical data sheets for Specialty Minerals products
- Request a sample
- Specialty Minerals Plant Locations and Profiles
- Quality and ISO at Specialty Minerals