Abstract: Dyes transfer or color contamination is a common problem in garment laundering. The effects of water hardness, washing temperature, pH value, and polyvinylpyrrolidone (PVP) concentration on the transfer properties of nine different structured direct dyes were studied. The results showed that the flat structure of the direct dyes and the ability of hydrogen bonding have a great influence on color contamination. The increase of water hardness has a positive effect on the transfer of eight direct dyes, while the increase of washing temperature has an inhibition effect on the transfer of seven direct dyes. Increased pH value promotes the transfer of seven direct dyes. And PVP has a significant inhibition on the transfer of all direct dyes. Therefore, reducing water hardness and pH value and properly increasing washing temperature in laundering can inhibit the transfer of most direct dyes.

Key words: direct dyes; dye transfer; water hardness; pH value; washing temperature