DIRECT DYES FOR TEXTILE DYEING
Sinardirect dyes :
These types of direct dyes used for dye cellulose fibers and its blend by exhaustion and padding methods, and also can be applied to rayon, silk, etc. and have particularly an excellent Wet fastness. These dyes are excellent for exhaustion dyeing of cellulose fibers. By adopted SDC method, Sinardirect colors are classified as follows:
• Class A: Self-levelling dyes:
These Direct Dyes have good migration property and level easily. They may dye evenly at first but further dyeing at a higher temperature will bring about even distribution of the dyes.
Class B: Salt controllable dyes:
These are dyes of poor migration power or poor levelling properties. They must be applied in a level manner by gradual addition of the salt because of the diffusion rate of the dye in the fibre is relatively slow, and the exhaustion takes place in proportion to the diffusion of the dyes.
Class C: Temperature controllable dyes:
These dyes are not self levelling and highly sensitive to salt. Owing to these dyes strong affinity, the exhaustion cannot adequately be controlled by addition of salt alone. It is necessary to raise the temperature slowly while making small addition of salt.
The dyeing procedure depends on the respective specific conditions. The dyeing diagram is therefore only suitable as a guide. We recommend using a buffer mixture to control the pH to the constant value required particularly where water conditions vary after treatment; when dyeing with Sinardirect Fast Black B H/C and Black L, add soda ash the start (pH 8-9) and refer to group 2 for Salt amount.