Polyester microfiber has usually greater dye uptake than normal denier polyester fiber in same dyeing condition. In spite of this high dye uptake dyed microfiber fabric has not only low visual colour depth but also poor washing fastness property. In order to study high colouring dyeing technology and high washing fastness of polyester microfiber, dyeing property of polyester microfiber was investigated according to the dye solubility and particle size of used disperse dyes in aqueous dye solution. After disperse dyeing, dyed fabric with disperse dye was redyed with a vat dye without reduction clearing in order to obtain a high washing fastness property. The result were as followings ; A small particle sized disperse dyes such as C. I. Disperse Blue 56 and Red 60 showed high rate of initial exhaution compared with a large particle sized disperse dyes like C. I. Disperse Blue 165 and Red 343. In study of dyeing property of polyester microfiber with C. I. Vat Blue 1, polyester microfiber could achieve high dye uptake at a given optimum vatting process conditions. On the other hand, in consecutive dyeing with disperse and vat dye, K/S value of polyester microfiber with a small particle sized disperse dye increased without reduction clearings, but K/S value of polyester microfiber with a large particle sized disperse dye decreased with reduction clearings.
