Fixation and after treatments

If a textile print is washed soon after printing and drying, most of the colorant will be washed away. An appropriate fixing technique is therefore necessary. Fixing techniques are seldom completely successful and it is usually necessary to follow fixing with removal of the unfixed dye, thickeners and other auxiliary chemicals by a washing process. The efficacy of the fixing and subsequent washing process is extremely important to the quality of the print, and mistakes made at this stage of the printing process can be very costly.

Pigment prints are fixed to the fabric simply by baking printed fabric. When the fabric has been printed to an adequate temperature the binder forms a continuous film that incorporates the pigment particles and sticks to the fibre surface. At the same time, if the temperature and pH conditions are suitable, cross-linking between the binder molecules is achieved.

Printed dyes are usually fixed by a steaming process, the steam providing the heat and the vehicle for transfer of the dye from the printing paste to the textile fibre.