Preparation And Properties Of High Silica Content Silicone Acrylic Emulsion

Organosiloxane-modified acvlate latex does not also avoid that membrane of acrvlate latex becomes sticky when it is heated and crisp when it is exposed in the cold environment, but obviously improves the coating of weather resistance, stain resistance and water resistance. And thus it is widely used in the field of architectural coatings and has great application value and broad market prospects. Nowadays it is usually prepared with vinyl silicane coupling agent as the silicone materials. However, vinyl siloxane tend to hydrolysis and thus produces gelatin.which restricts the organosiloxane content (mass fraction of organic silicon monomer among the total monomers)and thus makes some effects on modifying of oganosiloxane.Organosilicone-modified acylicate latex was synthesised by two steps with tetramethyl tetravinyl cylotetrasiloxane as organosilicane monomer, and methyl methylacrylate (MMA). butylacrylate (BA), acrylic acid(AA) as acrylate monomer. Vinyl-modified silicone emulsion was prepared by ring-opening hydrolysis reaction.which then participated in the free radical copolymerization with acylicate monomers.Effect of temperature, time of reaction, catalyst, emulsifier on vinvl-modifled siloxane emulsion was svstematicalk studied. The results showed that the conversion rate reached72.78%and the stability was high when DBSA amount of catalyst was5%of the mass of vi-D4. the amount of SDBS/OP-10emulsifier3%of the mass of the silicon monomer, both the mass ratio of2:3. at80℃throughout polymerization6h.With pre-emulsion acrylic monomer dropping method, time of which was2h, and vinyl siloxane emulsion after adding ways time of which was3h, the siloxane-acrylate emulsion was polymerized under the copolymerization temperature of80°C and pH value of6～7according to the following ratio: soft acrylate monomer to hard acrylate one as1:1.2, functional acrylate monomer with amount of1g, anionic emulsifier to nonionic one as2:3with an amount of3%, oxidant initiator to reductant one as3:2with an amount of0.4%, water with an amount of55%of total mass. with siloxane content of20%. The designed experiment enabled an effective control of gelatin and realization of high conversion of monomer with excellent emulsion membrane performance. The IR spectrum of the siloxane-acrylate latex film indicated that copolymerization of vinyl polysiloxane with polyacrylate performed well.