Solvent-free fatty acid modified polyurethaneacrylic hybrid dispersion (PUA) coatings and their performance

 
A novel solvent-free fatty acid modified polyurethane acrylic hybrid dispersion´PUA´is prepared by the polymerization of acrylic monomers in the presence of a fatty acid modified polyurethane, the acrylic polymers is not grafted to the polyurethane during the polymerization. In addition, a variety of cross-linkable groups can be introduced in the acrylate conveniently (AAEM, Ketone-Hrdrazide, etc.) to obtain higher molecular weight and better chemical resistance. When used in the 1K floor coating applications, it shows rapid hardness development, good scratch resistance and excellent black heel resistance; Furthermore, when the fatty acid modified polyurethane pre-polymer is terminated by hydroxyl, meanwhile, introducing the hydroxyl acrylate monomers(HEA,HEMA) to the acrylic polymers, a hydroxyl-functional solvent-free fatty acid modified polyurethane-acrylic hybrid dispersion(0H-PUA) can be easily obtained, which has a hydroxyl group content, based on resin solid, of 0.5-6wt% with high solid content(~40%),while ordinary OH-PUD to be a gel with high hydroxyl group content. The fatty acid modified OH-PUA resin has a multiple film formation mechanism, which can be cured by NCO/OH linking , oxidation linking and ketone-hrdrzide linking. It can be used in 1K coating applications due to the fast drying rate and good early resistance. Compared with the traditional 2K system of secondary dispersions of hydroxyl-functional polyacrylate, it has lower VOC, faster drying rate and better early resistance. Also, It shows better fullness than OH-PA emulsion. The fatty acid modified OH-PUA resin is an easy and economical solution to balance the performance of waterborne coatings, which can be used in various applications, such as DIY, industrial wood coatings and metal coatings.