Polymeric coatings based on acrylic resin latexes from miniemulsion polymerization using hydrocarbon resins as osmotic agents

Abstract

Waterborne acrylic resins with a solid content higher than 40 wt % were obtained by miniemulsion polymerization of methyl methacrylate, butyl acrylate, and acrylic acid using a hydrocarbon coumarone-indene resin (HCR) as osmotic agent. HCR is a cheap polymer widely used for coatings and pressure-sensitive adhesives. The resin leads to a higher hydrophobicity for the acrylic latex film and acts as osmotic agent in miniemulsion polymerization preventing Ostwald ripening, leading to latexes with particle sizes, size distributions, and stability comparable to those obtained using n-hexadecane as osmotic agent. However, the monomer conversion and molecular weight were lower, indicating the occurrence of a chain-transfer reaction. Atomic force microscopy analysis demonstrated that a smooth film surface with phase-separated morphology was formed when using HCR. Faster film hardness development was achieved with HCR comparing with hexadecane. Compared with market standard in a paint formulation, a similar performance was achieved. © 2014 Wiley Periodicals, Inc.