Study On The Synthesis Of Organosilicon-modified Acrylic Emulsion And Preparation Of Exterior Paint With High Weather-durability

Waterborns have been experiencing technological growth for the past 30 years, latex paint especially the exterior paint is very popular at present since the environmental concern were highlighted. Using waterborns as exterior coating is an orientation for building coating development, high weather-ability latex paint will be applied widely because of the unique properties.The organosilicon acrylic latex is an exterior paint binder with excellent weather durability and contamination resistance. In order to synthsis the organsilicon-modified latex, a core-shell structure acrylic latex was studied firstly, the influences of emulsifiers such as the concentration of emulsifies, the ratio of anionic to nonionic emulsifier etc on the storage stablitity and Ca²⁺ stability were reserched. The operation parameters such as polymerization temperature, the concentration of initiator and emulsifiers which concerns with the synthetic rate were also investigated.Octamethylcyclotetrasiloxane(D4) was first selected as a modified organosilicon monomer which was used to synthesis of OH^--terminated polysiloxane . During the preparation of OH -terminated polysiloxane, the factors such as composite emulsifiers, initiator, polymerization temperature, were considered. By means of pre-emulsification and ring-opening polymerization of D4, the properties of D4-modified acrylic latex, included blend and grafted modification, were fully investigated, the results show D4 is a good organosilicon monomer, but there were not enough linking points between the polysiloxane and the acrylic latex. The effects of polysiloxane on the acrylic latex performance were obvious, it can improve the weather-resistance through the introduce of silicone, and improve the water-resistance by reducing the latex surface tension.Hydrolyzable organofunctional silanes (OFS) were selected as crosslinker to improve the compatibility between the silicone and organic polymer, the kinetics and fundamental aspects of alkoxy silane hydrolysis and condensation were studied with the gas chromatography (GC). Through the vinyl group and the alkoxy group of the...