The Adhesive Preparation For External Thermal Insulation Systems Based On Eps

With the approaching of energy crisis and the continuous improvement of environmental protecting, building energy conservation has received more and more attention. As the current mainstream of the construction energy-saving measures, expanded polystyrene (EPS) exterior insulation and finish systems are widely used.Adhesive which attach EPS to wall is the key of system's safety and durability.In this paper, "particle design" method was introduced to synthesize an emulsionadhesive with core-shell structure by using ammonium persulfate (APS) as initiator, sodium dodecylsulfate (SDS) and Alkylphenol polyoxyethylene(10)ether (OP-10) as composite emulsifier. The adhesive was prepared using pre-emulsion and semi-continuous seeded emulsion polymerization technology, which had a soft core of P(VAc/BA) and hard shell of P(St/BA). The test results showed that both the original and water-resistant adhesive strength were qualified to national standards JG149-2003《expansion of polystyrene board thin plastering exterior insulation system》.In this paper, the impact factors of pre-emulsion stability were studied. Through designing an orthogonal experiment of four factors and five levels, the best pre-emulsification process conditions were obtained: emulsifier amount 4%, pre-emulsification temperature 30℃, monomer dropping time 30 min, blender rate 560 r/min, stirring time 25 min. In this paper, hunger-dropping rate of shell pre-emulsion was also determined: results show that under the present system 23.75 g/h satisfy the hunger-dropping.The synthesis conditions of emulsion polymerization which affect emulsion performance and film properties were studied, and better reaction conditions were obtained: reaction temperature 78℃; Emulsifier amount 4%; emulsifier ratio SDS: OP-10 = 3:2; initiator 0.4%; core-shell proportion 8:2; functional acrylic monomers 3%. Under these conditions, the polymerization process was smooth and resulted emulsion was milk-white, which had a good film-form performance at room temperature. Its water-resistant and alkali-resistant performance was also good.The morphology of emulsion particles was characterized by infrared spectroscopy (IR), dynamic mechanical analysis (DMA) and particle size analysis. The results indicated that the emulsion adhesive had two glass transition temperatures, and the complex particle size was significantly larger than that of the core, which confirmed the existence of a core-shell structure.