Study on Ambient Curable Emulsion Coatings with Primary Amine/ Epoxy Type as Crosslinking Agents

Abstract: An unsaturated primary amine (UPA) was synthesized by using maleic anhydride and ethylene diamine using THF as the solvent. The structure of the UPA product was confirmed by FT-IR and H1-NMR techniques. In the first part of the thesis, the feasibility of emulsion copolymerization for UPA, styrene and (meth)acrylate was investigated. And the latex particles prepared were characterized by FT-IR. The effects of the dosages of UPA and emulsifiers including Iegpal CO-436, MS-1 and OP-10/SDS on the stability of emulsion system were investigated. The core-shell latex particles were prepared, in which primary amine group was located both in the core (labeled with C_(UPA)S) and in the shell (labeled with CS_(UPA)), respectively. The prepared emulsion polymer acted as the first component of ambient curable two-component emulsion coatings. The second component was prepared by emulsifying ethylene glycol diglycidyl ether in water. The two components were blended with a certain molar ratio and the composite emulsion obtained was dried to form a film under ambient temperature. The effects of the location of primary amine group in the core-shell latex particles, as well as UPA dosage and annealing time, on the tensile strength of the emulsion films were studied. The effect of UPA dosage on the water resistance of polymer films prepared from C_(UPA)S emulsion was studied. The heat resistance of the crosslinking films and non-crosslinking films from C_(UPA)S emulsion was also investigated. The tensile strength of emulsion films increases with increasing annealing temperature. For the CSUPA emulsion films the tensile strength increases firstly and then decreases with increasing UPA dosage; for the CUPAS emulsion films the strength of emulsion films deceases with increasing UPA dosage. And the tensile strength of the films from the C_(UPA)S emulsion exhibits more excellent than films that of films from the CS_(UPA) emulsion. Water resistance was improved with the increasing UPA dosage. The heat resistance of the C_(UPA)S emulsion films is better than that of the non-crosslinking emulsion films. In the second part of the thesis, the one-component ambient curable latex particles were prepared successfully by using a localization technology, in which the crosslinking functional group primary amine was located in the core part of the latex particle, while the epoxy in the aqueous phase, respectively, with a shell of crosslinking copolymer using ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent laying in between isolating the two crosslinking groups. The effects of UPA and EGDMA dosages as well as annealing temperature, on the tensile strength of emulsion films were all investigated. The effects of UPA and EGDMA dosages on water resistance and organic solvent resistance of emulsion films were also discussed. The formation of interpenetrating network(IPN) was suggested during the film forming by diffusion of poly(glycidol methacrylate) chains from the water phase into two neighbor polymer emulsion, as well as the interdiffusion of polymer segments across the boundary between the adjacent cells. The experimental results show that the tensile strength of emulsion films firstly increases and then decreases with the increase of the UPA and EGDMA dosages. The water resistance is improved with increasing the UPA and EGDMA dosages. The organic solvent resistance, however, is less sensitive to the amount of UPA used…
Key words: Core/shell latex particles; Ambient cure; Primary amine/epoxy group; Localization technology; IPN structure

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