Silica As an Anti-Blocking Agent in PET and BOPET Films

Optimizing performance across a broad range of markets

End-use market expansion

Polyethylene terephthalate (PET) plastic films and sheets are used in a variety of markets, from face shields to food packaging to solar panels and even electronics. PET demand continues to rise because of its unique combination of clarity, high tensile strength, electrical insulating, as well as high properties as a barrier to oxygen, carbon dioxide, and water-vapor.

Lifestyle changes, the rising adoption of e-commerce, and the COVID-19 pandemic have driven an increase in demand for food packaging. As consumer markets become more sophisticated, PET film will also play a strong role in consumer and automotive electronics and solar energy.

Biaxially oriented PET (BOPET) is a polyester film made from stretched PET and is prized for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aroma barrier properties, and electrical insulation. Asia is the largest producer and user of BOPET films and sheets. Local governments are encouraging investment and localization of high-end BOPET film production. 

A common challenge in PET and BOPET film production

Large-scale production of PET and BOPET films is relatively straightforward except for a common problem: blocking. It occurs when PET and BOPET films stick together as a result of being wound on a roll and stacked during storage.

To prevent blocking, polymer film manufacturers add low concentrations of silica particles during production. These anti-blocking additives create a microscopically rough surface that prevents the film layers from sticking together, which facilitates film unwinding and ultimately production.

Environmentally friendly anti-blocking solution

With a state-of-the-art portfolio, Grace’s global silica gel network is well positioned to serve a vast majority of our customers’ end-use applications. 

Grace’s SYLOBLOC^® silica is a noncrystalline, high-purity silica that is not classified as toxic. A trusted processing aid for resin producers, masterbatch, and compounding companies, SYLOBLOC^® silica is consistently produced at the right particle size and pore volume to deliver microroughness that retains optical and physical properties required for end-use applications.

With high dispersibility, SYLOBLOC^® silica ensures maximum anti-blocking efficiency and low trace contaminants and is approved for food contact.

Grace also specializes in particle and material engineering. Contact us and work with our experts to customize silica-based anti-blocking additives for your specific porosity, particle size, and functionality needs.