Physical Properties of High-Solid Coatings with Acrylic Resins Containing Acetoacetoxy Group and Allophanate-Trimer

Copolymers (HSA-98-20, HSA-98-0, HSA-98+20) which are acrylic resin containing 80% solid content were synthesized by the reaction of monomers, including methyl methacrylate, n-butyl acrylate, and 2-hydroxyethyl acrylate with a functional monomer, acetoacetoxyethyl methacrylate (AAEM), which may give improvements in cross-linking density and physical properties of films. The physical properties of prepared acrylic resins, containing AAEM, are as follows : viscosities, 1420 similar to 5760 cps; number average molecular weight, 2080 similar to 2300 g/mol; polydispersity index. 2.07 similar to 2.19; and conversions, 88 similar to 93%. In the next step, high-solid coatings (HSA-98-20C. HSA-98-OC, HSA-98+20C) were prepared by the curing reaction between acrylic resins containing 80% solid content and isocyanate at room temperature. Various properties were examined on the film coated with the prepared high-solid coatings. The introduction of AAEM to the coatings enhanced the abrasion resistance and solvent resistance, which indicated the possible use of high-solid coatings for top-coating materials of automobile. Since the curing by viscoelastic measurement occurred in sequence of HSA-98+20C>HSA-98-OC>HSA-98-20C, it was concluded that the curing rates became faster with incresing T-g values.