| With the consistent technology improvement and increasing market needs, coating industry is developing rapidly. Nowadays, an increasing number of people pay attention to environment and healthy related issues, while traditional solvent-based coatings, which contain large amounts of volatile organic compounds(benzene, toluene, formaldehyde and etc.), cannot fulfill market demand. Therefore, it is imminent to develop the modern green paint. However in water glass painting field, due to high finish of glass surface and large surface tension of water, the adhesion between painting and glass is very poor, which cause low hardness, poor wear resistance and many other shortcomings.The first part of this paper used silicone to modify acrylic resin by emulsion polymerization. It was a chemical process in which silicone monomers were introduced on the molecular chain of acrylic resin; as a result, chemical bonds were created between these two resins which had extremely different polarity; thus a hydroxyl-containing silicone acrylic emulsion has been successfully synthesized. In the second part, combined with amino resin, such modified resin was used as main film-forming resin to prepare an aqueous glass painting. And the influence of different content on coating properties was investigated and the best ratio was defined. Details are listed as follows:(1) A chemical method, semi-continuous-seed emulsion polymerization, was employed to introduce the silicone monomers onto the molecular chain of acrylic resin, aiming to synthesize a modified acrylic emulsion with silicone and hydroxyl. According to the infrared analysis, silicone monomer has been successfully connected to the acrylic resin molecular chain. And when the amount of organic silicone monomer(Grade 172) was 7%, the HLB value of the emulsifier system was 16(contents was 1%), the ratio of soft and hard monomer was 1:2 and reaction temperature was at 70℃ for 4 hours, the best emulsion could be prepared, whose conversion rate could reach 98%, gel fraction was less than 1%, and the average particle size was 120nm; what’s more, the particle size distribution was smaller than 0.1, which also had a good stability and adhesion.(2) In the second part of this paper, combined with the amino resin, the modified resin was used as the main film-forming resin to prepare aqueous glass paint. The factors which affected coating’s properties were studied. Infrared analysis and thermal gravimetric analysis showed that after the crosslink reaction, hydroxyl group in the matrix resin had completely reacted with the amino resin, the coating’s heat resistance had a significantly improvement than the one without crosslink. Using RB747 amino resin as the curing agent, when the ratio of matrix resin and amino resin was 4: 1, the ratio of dye(Fe2O3) and resin was 0.8, leveling agent(Grade: G70) was 0.2%, defoamer(Grade: 532) was 0.1%, and the paint was baking for 30 minutes at 150℃,coating had good properties, of which adhesion level was 1, hardness was 3H and water resistance was up to 5 days. |
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