Abstract:

A kind of epoxy resin was chain-extended hy polyamide , cationic-modified , hlended with curing agent of polyurethane , and then emulsified hy means of phase inversion. Thus，an epoxy-polyurethane emulsion was prepared. The viscosity and stahility of the emulsion were then investigated with such difIerent parameters as the solvent dosage and mixing ratio , the relative molecular mass of the modified epoxy resin , the water soluhility and the curing agent dosage. It is found from experiments that the mass fraction of the solvent in resin has a critical value of 8.8%. When the solvent dosage is more than 8.8% , the phase inversion is difficultωoccur and the prepared emulsion is unstahle. On the contrary , this is possihle when the dosage is less than 8. 8%. Moreover, it is indicated that , as the water-soluhle solvent of ethylene glycel mono-hutyl ether is partly suhstituted hy the hydrophohic solvent of xylene , the viscosities of the resin and the emulsion hoth greatly decrease ，that the modified epoxy resin is easily soluhle when the polyamide dosage is 6.0% - 6.5% that of epoxy resin and the neutralization degree is 65 % , and that the prepared emulsion is very stahle in a curing agent dosage of 15. 0% - 20. 0% .

Key words: epoxy-polyurethane emulsion, phase inversion, viscosity, stahility