Study On Preparation And Performance Of Water-based Silicone Release Agent And Fluorinated Polyacrylate Emulsion

Release agents are chemicals used to prevent mold adhesion,which is essential in metal die-casting and polymer forming processes.In this thesis,modified silicone oil that is the recent research hotspot in industries was applied to replace the conventional polyorganosiloxane as the water-based silicone release agent.The mechanical shear emulsification was selected to prepare the water-based silicone release agent.The obtained release agent with excellent performances is expected to be used in aluminum alloy die-casting industries.The research work of this thesis is summarized below:1.The long-chain alkyl silicone oil and phenyl silicone oil were utilized as the main materials with a composite emulsifier and supplemented by other additives.The water phase pre-emulsion was treated by high-speed shear first and then continuously fed materials to produce the water-based silicone release agent.Through experimental explorations,the best preparation condition has been determined as follows:15%mixed silicone oil(the ratio of long-chain silicone oil and phenyl silicone oil is 4:1),compound emulsifier(HLB value is 9.5)with the added amount of 25%of added silicone oil,0.5%thickener,0.2%defoamer,and 0.75%extreme pressure agent.Besides,the added amounts of antioxidant,2,6-di-tert-methyl-p-cresol,and bactericidal preservative are 0.1%and 0.15%,respectively.The shear emulsification time is 15 minutes.The as-prepared samples have been characterized to measure its particle size,surface tension,wettability,stability,high-temperature film formation,and corrosion rate of aluminum alloy sheets.In addition,the batch of samples were tested by a domestic aluminum alloy die-casting manufacturer and compared with commercial products.The performance indicators of the samples prepared in this thesis are equivalent to those of the foreign sample B,and are superior to those of the domestic samples C and D.2.A fluorinated acrylate copolymer emulsion was prepared by using fluorine-containing acrylate as the main raw material,functional monomers and long(short)chain acrylate monomers as copolymer elastomers,and a composite emulsifier.The high-speed shear and free radical copolymerization methods were applied.This project studies the effects of monomers,emulsifiers,co-solvents,initiator types,dosages and reaction time on the performances of polymer emulsions.Using FT-IR,XPS,GPC,TEM,TGA,DSC,surface tension meter,laser particle size distribution meter,etc.,the structures and performances of the prepared polymers were characterized and determined.The results showed that the polymer emulsion could form a uniform film,and the surface fluorine element content(22.8%)was much greater than the theoretical value(14.8%)and the measured value(12.66%).