Insights into the preparation of water-based acrylic interior decorative paint: tuning binder’s properties by self-crosslinking of allyl acetoacetate - hexamethylenediamine

Abstract

In order to study the self-crosslinking mechanism of an acrylic-based copolymer emulsion, the stable, one pack (1 K), room temperature curing copolymer was synthesized by semi-continuous seeded emulsion polymerization using butyl acrylate (BA), styrene, acrylic acid (AA), acrylamide and allyl acetoacetate (AAA) as a monomers and hexamethylenediamine (HDA) as a crosslinker. Fourier transform infrared (FT-IR) spectrogram confirmed that crosslinking reaction between carbonyl groups of AAA and amine groups of HDA can occur during film formation at low temperature, even at ambient temperature. Differential scanning calorimeter (DSC) analysis indicated that glass transition temperature of crosslinked film was increased by 8 °C. Thermogravimetric analysis (TGA) curves verified that crosslinking improved the thermal stability of a film. Also, the prepared films were tested by dynamic mechanical analysis (DMA) for the determination of storage modulus and tangent delta. Crosslinking was enumerated through degree of swelling measurement. It was seen that degree of crosslinking of a film was increased with increase in AAA content. Other properties of acrylic binder were determined by viscosity, solid content, pH, water resistance, gloss, % elongation, particle size, pencil hardness, flexibility and freezing-thawing resistance. Subsequently, white latex paint was prepared using acrylic binder. Physical and performance properties of paint were determined by viscosity, solid content, water uptake, percent elongation at break, pencil hardness, flexibility, impact resistance, dirt pick-up resistance, stain resistance, scrub resistance and coverage capacity. The results confirmed that acrylic binder with 2.0% AAA leads to a good performance and has potential application for interior decorative paints.