Chemical skills of various dyes

1. Direct dyes:

Direct dyes have relatively good heat-resistance stability. Direct dyes can be dissolved by adding soda ash and soft water. When mixing materials, first use cold soft water to make dyes into a slurry, then boil soft water and stir to dissolve, heat water to dilute, and add water to the specified level after cooling. liquid volume.

2.Reactive dyes:

This type of dye is not heat-resistant and easy to be hydrolyzed at high temperature. It is advisable to use cold soft water to make a slurry. Then, according to the hydrolytic stability of different dyes, use soft water of appropriate temperature to dissolve, heat soft water to dilute, and add soft water to the specified liquid volume after cooling.

Low temperature type (X type): use cold water or 30-35 ℃ warm water (basically eliminated)

High temperature type (K type, HE type, etc.) with 70-80 ℃ hot water

60-70℃ hot water for medium temperature type (KN, M type)

Use 90 ℃ hot water for low solubility

3. Vat dyes:

The dissolving process of vat dye is a reduction reaction process. When dissolving, the dissolving temperature should be determined according to the reducing conditions of the reducing agent used. For example, the commonly used reducing agent for vat dyes is hydrosulfite, and the optimum temperature for use in the solution is 60 °C. If the temperature is too high, it will cause a large amount of hydrosulfite to decompose.

(1) Full bath method:

Put the dye into the dyeing cup, add red oil and a small amount of warm soft water and mix thoroughly, then add the specified amount of caustic soda and insurance powder, add soft water to the required bath volume, and restore at 55 ° C.

(2) Dry cylinder method:

Put the dye into the dyeing cup, add red oil and a small amount of warm soft water and mix thoroughly, then add two-thirds of the amount of caustic soda and hydrosulfite, so that the amount of dye liquor is one-third of the total amount, according to the reducing conditions of the reducing agent used to determine the temperature of dissolution. Add the remaining caustic soda and insurance powder to the dye cup, and add soft water to the desired bath volume.

4. Sulfur dyes:

Accurately weigh the required amount of dye into a beaker, make a slurry with cold soft water, add the pre-dissolved sodium sulfide dye solution, and boil for 10 minutes. Heated soft water for dilution, and after cooling, add soft water to the specified amount.

5. Disperse dyes:

If the temperature is too high, disperse dyes are easy to crystallize. When mixing materials, it is advisable to use cold soft water to mix the slurry first, then use cold soft water below 40 °C to make the material, and add soft water to the specified liquid volume.

6. Acid dyes:

Acid dyes have relatively good heat resistance stability. When acid dyes are made into materials, first use cold soft water to make dyes into slurry, then boil soft water and stir to dissolve, heat soft water for dilution, and add soft water to the specified liquid volume after cooling.

7.Cationic dyes:

Cationic dyes have relatively good heat-resistance stability. When compounding, first use concentrated acetic acid (solubilizer) to make the dye into a slurry, then dissolve it with boiling soft water, heat it for dilution, and add soft water to the specified volume after cooling.