'H' Dyes have low reactivity and needs a slightly higher temperature, usually about 80°C and higher PH about 11 is required to fix the dyes. It is substantively towards substrates is low. These dyes are mainly suitable for textile printing because of relative inertness of dye towards alkali at room temperatures, which allows formulation of stable print paste containing both dye and an alkali. The fabric to be printed must be properly desized to make absorbent. Mercerisation of cotton fabrics and causticization cellulose fabrics yield brilliant and deep prints. Hot brand dyes also known as 'P' dyes.
1. Most suitable for use silicate, hot silicate pad-batch and steaming printing.
2. Brilliant and deep printing shade. Good wash fastness.
3. Both one phase and two phase method can be used.
4. Good soluble and high level of fixation is possible by yielding fast and hues.
5. They have good all around fastness and wash-off properties.
Key to Abbreviations
ND = Non Dischargeable
D = Dischargeable
G = Good
M = Medium
F = Fair
P = Poor
S = Suitable
NS = Non Suitable
L = Less Suitable