Synthesis And Application Of Silicon-modified Polyacrylate Microemulsion In Electrostatic Flocking

Silicon-modified polyacrylate microemulsion with core-shell structure was successfully synthesized by seed emulsion polymerization and two step polymeric process. Firstly, the vinyl-silicone seed microemulsion was prepared. Then, on the basis of the seed microemulsion, several acrylate monomers were added to polymeric system to synthesize silicon-modified polyacrylate microemulsion with core-shell structure. At the same time, the structure and performance of copolymer were analysed. Lastly, the polymerization product was applied into electrostatic flocking and the flocking results were evaluated.During the synthesis of silicone seed emulsion, the stabile vinyl-silicone microemulsion was sucessfully synthesized by D₄ open-ring polymerization under the catalysis of dodecylbenzenesul-fonic acid with nonionic surfactant XP70 as emulsifier and KH570 as grafting reagent. The effects of the amount of nonionic emulsifier, the amount of catalyst, the amount of D₄ monomer and KH570 on polymerization reaction and emulsion stability were systemically investigated. The optimum reaction conditions were acquired when the amount of XP70 was 1.2%,catalyst was 2.4% ,D₄ monomer was 20% and the KH570 was added two hours later after D₄ and the amount was 4%.During the synthesis of silicone-acrylic microemulsion with core-shell structure, the APS was selected as the initiator, methyl methacrylate as the hard monomer, butyl acrylate and ethyl acrylate as the soft monomers, and acrylic acid as the functional monomer. The effects of the polymerization temperature, reactive time, the amount of emulsifier, initiator, cross-linking monomer,the Tg of the copolymer and the silicone seed emulsion on polymerization emulsion properties were systemically investigated. At the same time, the performance of polymerization emulsion was evaluated by conversion rate, coagulation rate, particle size, stability, water absorption of the emulsion film and film formation. The experimental results showed that the better silicone-acrylic microemulsion with core-shell structure can be prepared when the polymerization temperature was 80℃, the reaction time was 2h, the amount of emulsifiers was 2.5% and the mass ratio of anionic emulsifier to nonionic emulsifier was 1:2,the amount of initiator was 0.5%, pre-emulsion dropwise time was 30min, the Tg of copolymer was -20℃, the amount of DAAM was 3% and silicone seed emulsion was 15%.The structure and performance of copolymer were analysed by FTIR、DSC、TG、NMR and rheological. The test results showed that the graft copolymer was successfully prepared by the copolymerization of vinyl-polysiloxane and polyacrylates. The silicone-acrylic microemulsion had better stability, film formation and heat resistance than polyacrylate emulsion, whose average particle size was about 80nm.With regard to the application of acquired electrostatic flocking adhesive, the effects of different coating weight, baking temperature, baking time and the amount of silicone seed emulsion on flocking results were discussed using the method of flocks moving up respectively. The experimental results showed that the excellent flocking results were acquired after the application of silicone-acrylic electrostatic flocking adhesive, especially in environmental protection, low baking temperature, flocking fastness and handle etc .The better flocking product can be prepared when the coating weight was 250g/m², the baking temperature was 80℃, the baking time was 4min and the amount of silicon seed microemulsion was 15%.The terminal electrostatic flocking fabrics had high flocking fastness, soft feel, good antistatic and crease recovery properties, whose flocking fastness≥6100 times, bending length is 1.80cm,half life is 0.62s and the rank of appearance after laundering is 4-5,in line with the high-class products of FZ/T64011-2001 standard.