As the search continues for lower material costs, without sacrificing performance or processability, hollow glass microspheres are getting more attention. Reducing density with additives is not new, but bubbles are showing advantages.
We have developed a low-density resin formulation that reduces the weight of parts molded of TPO (thermoplastic polyolefin) by up to 20%. It’s a masterbatch bulk resin additive that incorporates hollow glass microspheres to displace resin and reduce part density in molded, thermoformed, and extruded products.
Mandated standards for Corporate Average Fuel Economy (CAFE), along with the drive to reduce industrial emissions and achieve more sustainable production methods, have led to a growing demand for enhanced TPO production methods, hollow glass microspheres additives in our masterbatch material displace hydrocarbon-based resin content and lighten parts to help cut transport fuel consumption.
Use of density-reducing agents for filled TPO raw material is not a new concept. While various filler materials have been used to reduce TPO part density, hollow glass microspheres have significant process and resin displacement advantages over alternate fillers. We’ve found that the addition of hollow glass microspheres yields secondary benefits to TPO components as well, including improved part stiffness, greater dimensional stability, and reduced shrinkage.
Traditional resin-displacement mineral fillers such as cenospheres, asbestos particulate, chopped glass fiber, and calcium carbonate (CaCO3) have considerably less volume per unit weight than hollow glass microspheres. For example, 1 kg of typical hollow glass microspheres material has a volume of 1666.7 cm3, while the equivalent weight of CaCO3 displaces only 370.4 cm3. Thus its resin displacement potential per unit of weight is only a fraction of that of hollow glass microspheres.