Research Of Organic Silicone Modified Styrene Acrylic Emulsion

With the development of technology and improvement of living standards, consumers have been paying more and more attention to environmental protection and human health. Meanwhile, policies and laws related to environmental protection are gradually implemented and modified. Energy conservation and environmental protection have already became the two important issues that organizations of coating material worldwide are facing. The research and development of water-soluble coating is valued globally. Water is used as medium of water-soluble coating whose main component is emulsion. Emulsion is an important film forming material and usually prepared by emulsion polymerization. Styrene-acrylic emulsion is one of the most common emulsion systems.Prepared by the co-polymerization of styrene and butyl acrylae, Styrene-acrylic shows excellent properties of both of them. Polystyrene performs low water absorption and can be gained at low cost. It, however, shows low impact resistance, stickiness at high temperature and fragility at low temperature. The introduction of acrylics can improve the impact resistance and toughness of polystyrene. Styrene-acrylic emulsion has good pigment affinity, chemical resistance, high glossiness and stain resistance, which is widely used in the surface of wooden furniture, metal surface coating and exterior architectural paint. However, styrene acrylic emulsion also has its own disadvantages including poor water resistance and oxidation resistance, Limiting the broader application of it.. As a result, modification of styrene-acrylic emulsion is necessary to improve its performance.Styrene-acrylic emulsion modified by D4 and A171 were prapared by semi-continuous emulsion polymerization using styrene and butyl acrylate as main monomers, arylic acid as functional monomer, APS as initiator and SDS/OP-10 as emulsifiers. Influence of emulsion polymerization process, types, amount and ratio of emulsifiers, polymerization temperature, addition time of monomers and initiator, ratio of main monomers, amount of organosilicone and concentration of initiators on performance of styrene-acrylic emulsion modified by organosilicone were investigated. The optimum formula was also determined. The emulsion products were characterized by laser particle analyzer, FT-IR, TGA, TEM and SEM. The results illustrate that styrene-acrylic emulsion shows best performance when the amount of D4 and A-171 is 8wt% and 3wt%, respectively. The addition of organosilicone can effectively improves the water resistance and heat resistance of styrene-acrylic emulsion.The impacts of several additives on coating performance were analyzed and optimum formula of coating was identified as follows: flatting agent 0.5wt%, dispersant 1wt%, thickening agent 0.4wt% and coalescent agent 5wt%. The coating prepared by the formula above possesses higher pencil hardness and lower water absorption.