Synthesis And Performance Of Two-component Acrylic Resins For Coatings

With increasingly stringent environmental laws and regulations on coating industry, the issues on the pollution in the process of coating preparation and use receive full attention. Compared with the traditional solvent-based coatings, high-solid coatings and water-borne coatings can greatly reduce the volatiles organic content(VOC),which lessen the environmental pollution effectively. In this paper, the structure and properties of high-solid acrylic resins and water-borne acrylic resins were studied in detail.The high-solid acrylic resins were prepared by solution polymerization using dropwise addition with monomer mixture and initiator solution synchronously. The influence of initiator, reaction temperature, the amount of chain transfer agent and copolymer composition on the coating resins properties was studied. The hexamethylene diisocyanate (HDI) trimer was employed as curing agent for preparation of acrylic coating film. The structure and properties of the film were characterized by fourier transform infrared spectroscopy (FTIR) and thermal gravimetric(TG) respectively. The results show that the styrene component in the copolymer formula can reduce the viscosity of the polymerization system dramaticlly, and can enhance the solid content in solution polymerization. By the control of initiator dosage, polymerization temperature and the ratio of reaction monomer, the ideal hydroxyl acrylic resin with70%solid content were prepared successfully. The optimal reaction conditions were as follows:reaction temperature95℃,3.0%initiator-to-monomer.In the preparation of water-borne acrylic resin, solution polymerization was firstly explored to synthesize the polymer having double-ended double bonds group and acrylic acid (AA), and the prepared acrylic resin copolymer with branched structure was consisted with acrylic monomers and functional monomer (AG). After salt forming reaction, the copolymer was crosslinked by amino resin (HMMM) to form interpenetration polymer network. The influence of the amount of acrylic monomer, the degree of neutralization and neutralization temperature on water-borne acrylic resin was investigated, and the properties of the coating film prepared by crosslinking reaction were studied.The results indicated that the water-borne acrylic resin modified by GMA could be prepared under the optimal condition:the neutralization temperature is50℃～60℃, the the degree of neutralization is70%～80%and the content of AA is8%～10%. GMA modified water-borne acrylic resin having branch structure result in wild molecular weight distribution. And it with the amino resin (HMMM) crosslinking curing of the paint film is better than the performance of the linear structure of crosslinking curing film. The visual inspection of coating film is flat and smooth, the hardness of film is4H, the adhesion strength is level2and the water-resistant level is3d.