Preparation of liquid polysiloxane-based anti-misting agents for application in release coatings

Abstract

Liquid polysiloxanes are prone to misting in coating processes performed at high roller speeds, and the addition of anti-misting agents is a cost-effective method to address this issue. In this work, a series of mildly cross-linked fluorinated polysiloxane-based viscoelastic fluids were synthetized via the successive hydrosilylation of (perfluorohexyl) ethylene (PFHE) and vinyl-terminated polydimethylsiloxane (PDMS-Vi) with hydride-terminated polydimethylsiloxane (PMHS). As anti-misting agents for high-speed coating process of silicone release agents, their inhibition efficiency can reach 92.1 % with a dosage of 4 wt%. It was also found that the physical properties, rheology, and molecular structure of the agents have various influences on inhibition efficiency depending on the anti-misting mechanisms. Additionally, the agents could significantly reduce the negative impact of coatings, and have no obvious adverse effect on the heat curing process or the transparency. The transparency of the films on the surface of the underlying polyethylene terephthalate (PET) substrate is still in excess of 95 %. Finally, the agents are conducive to improving the thermal stability of the films, and the results show that this type of viscoelastic fluids has the potential to be used in the industrial production of silicone release coatings.