Shining New Light on Opaque Polymer

By Heather M. Eckenrode, David M. Fasano

An opaque polymer* was developed in the 1970s to provide paint formulators with a light scattering pigment to supplement the use of titanium dioxide (TiO₂). The hollow-sphere structure of opaque polymer provides a controlled and consistent level of air void hiding in paint through the refractive index differential between the internal air void and the outer polymer shell. The encapsulated air voids provide hiding without the loss of resistance properties associated with other raw materials which provide hiding through increased film porosity.

Extensive research and practical experience demonstrate that opaque polymer may be used to economically replace 10 to 20% of TiO₂ in white and pastel architectural paints. Recent and continued increases in TiO₂ price have raised the formulated cost of all paints. As a result, there is growing interest in using opaque polymer at higher levels of TiO₂ replacement in white and pastel acrylics.

This interest extends to using opaque polymer in mid-tone tint bases, primers, and polyvinyl acetate (PVA) paints. Reformulation and performance studies coupled with a new proprietary reformulation tool demonstrate the expanded utility of opaque polymer in these formulation spaces. In addition, technology advances have led to the development of a next-generation opaque polymer that can be used in waterborne as well as solventborne alkyd architectural paints.