The ten parameters of reactive dye dyeing include: dyeing characteristics S,E,R,F values, migration index MI value, leveling factor LDF value, washable factor WF value, lifting force index BDI value/inorganic property value, organic property value (I/O), and solubility.
The ten parameters have significant guiding significance for the main properties of reactive dyes, such as dye uptake rate, directness, reactivity, fixation rate, level dyeing property, reproducibility, compatibility with mixed dyes and color fastness.
1. Directness
S represents the directness of the dye to the fiber, which is characterized by the adsorption rate after 30 minutes of adsorption before adding alkali.
Ii. Reactivity
R represents the reactivity of the dye, which is characterized by the fixation rate 5 minutes after adding alkali.
Iii. Dry dyeing Rate
E represents the exhaustion rate of dyeing, which is characterized by the final color depth and the ratio of the amount used.
Iv. Color Fixation Rate
F represents the dye fixation rate, which is the dye fixation rate measured after the floating color of the dye is washed off. The fixation rate is always lower than the exhaustion rate. The S and R values can describe the loading rate and reaction rate of reactive dyes, which are related to the dye's migration and leveling properties. The E and F values are related to the dye's utilization rate, washability and fastness.
V. Transstaining property
MI: MI=C/B*100%, where B represents the residual dye amount of the dyed fabric after the transfer dyeing test, and C is the dye amount of the white fabric after the transfer dyeing test. The larger the MI value, the better the leveling property. Dyes with an MI value greater than 90% all have good leveling properties.
Vi. Compatibility
LDF: LDF = MI×S/ELDF. When the LDF value is greater than 70, it indicates good leveling property. RCM: Reactive Dye Compatibility Factor, which consists of four elements: S,MI,LDF, and the half-dye time T of reactive dyes in the presence of a base. To achieve a high one-time success rate, the RCM value is generally determined within the following ranges: S in neutral electrolyte =70-80%, MI greater than 90%, LDF greater than 70%, and half-staining time greater than 10 minutes.
Seven. Easy to wash
WF: WF=1/S(E-F). Generally, when the fixation rate of reactive dyes is less than 70%, (E-F) is greater than 15%, and S is greater than 75%, there will be a large amount of floating color that is difficult to remove, and it cannot be used for concentrated dyeing.
Viii. Enhancing Capacity
BDI: Lifting Power Index, also known as dyeing saturation value. To increase depth, the amount of dye is generally increased. However, dyes with poor lifting power do not increase depth as the amount of dye increases to a certain extent. Test method: Taking the apparent color dosage of the dyed fabric measured under the standard chromaticity (such as 2% as the standard) as the benchmark, the ratio of the apparent color dosage of the dyed fabric of each chromaticity with gradually increasing dye dosage to the apparent color dosage of the standard chromaticity.
Ix. I/O Values
I/O value: In organic compounds, the hydrophobic (non-polar) part is called the organic group part, and the hydrophilic (polar) part is called the inorganic group part. The value is obtained by adding the values of different groups and then dividing the group values of polar and non-polar groups by the sum of them. The I/O value represents the distribution of dyes in fibers and dyeing solutions. This is also a very important indicator when choosing the three primary colors.
X. Solubility
The better the solubility of a dye, the wider its application range. There are two methods to enhance solubility: one is to add some specially structured wetting agents to make the dye quickly wet in water, and then use alkyl naphthalene sulfonic acid formaldehyde condensation series dispersants to make the associated molecules of the dye form monomers. The second method is the batch blending of isomers of reactive dyes.
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