Application of colloidal unimolecular polymer (CUP) particles in coatings

Colloidal unimolecular polymer (CUP) particles were prepared by the process of water reduction on copolymers containing hydrophobic and hydrophilic monomers at definite ratio using free radical polymerization. The CUPs are formed by the effect of hydrophilic /hydrophobic interactions of the polymer with a change in the solvent environment around them. Once formed these colloidal particles are thermodynamically stable with collapsed hydrophobic groups forming a spheroidal core and hydrophilic charges on the surface stabilizing the particle by the charge repulsion. CUPs contain only the charged CUP particles, water and counterions with all the functionality on the surface for further chemistry. CUP suspension with amine functional groups on the surface can react with epoxy groups and therefore can be used as a crosslinker for 2K epoxy coating. The cured films had comparable properties with commercial amine crosslinker at reduced VOCs. New regulations which reduce the level of volatile organic compounds (VOC) for architectural latex coatings usually necessitate a sacrifice in performance. The use of glycol has been shown to aid in both freeze thaw and wet edge retention. Loss of this VOC will therefore compromise both. With small particle size, CUPs offer a large amount of surface area with the large amount of non-freezable surface water. The presence of non-freezing surface water make CUPs a candidate as an additive for the wet edge retention and freeze thaw stabilizer for architectural paints. The use of CUP as wet edge retention additive and freeze thaw stabilizer is good alternative for the glycols used in paints and therefore lowers the VOC of architectural latex paints --Abstract, page iv