Printing of Silk With Acid Dye

Theory

Acid dyes are substantive to protein and some polyamide fibers including silk, wool, and nylon 6.6. The fixation processes are like those used for reactive dyes. After steaming with saturated steam, the printed fabrics are washed to remove excess dyes and thickening paste. The printing paste which is applied to textile material consists of dye water, thickener, and hydrocarbon solvent or oil. Once the acid dye printing paste has been applied to the textile material, steaming the printed pattern is necessary. The steam provides the water molecule and heat energy to enable the dye molecules of the printing paste to transfer from the fiber surface into the polymer system.

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Objectives

• To know about acid dye and silk fabric.
• To know about the recipe for printing on silk fabric.
• To know about the process of printing silk with acid dye.

Recipe

Chemicals / Parameters	Required Amount
Acid dye	2 gm
Glycerin	2.5 gm
Acetic acid	5 gm
Thickener	55 gm
Water	As required
Thickener Preparation
CMC	8 ml
Water	92 ml
Total	100 ml
Temperature	100℃
Time	10 minutes

Process Flow

Printing

↓

Drying

↓

Steaming (Temp ✕ Time – 100-105℃ ✕ 2-5 minutes)

↓

Soaping-Detergent-2 g/L (Temp ✕ Time – 70℃ ✕ 10 minutes)

↓

Washing

Working Procedure

1. First, prepared the thickener.
2. Then take the required amount of dyestuff in a bath.
3. Then added the required amount of chemical auxiliaries and thickener.
4. Then continuous stirring is done few minutes for mixing and preparing the print paste.
5. Then selected a block and took a fabric.
6. The block is touched with print paste and pressed upon the fabric.
7. After pressing, the block is put off from the fabric.
8. Then dried, steamed for absorbing dyestuff, and swamped for reducing unfixed dye
9. Then washed it.
10. Finally, the printed fabric is ready.

Functions of Chemicals Required

Acid dye: Acid dye is a dye that is applied to textiles at low pH. They are used to dye wool, silk, and nylon. Generally used to dye protein fibers. It is water-soluble and gives good light fastness. It contains sodium salt or sulphonic acid, so acid dyes are water-soluble. In water and acetic acid, the NH2 functionalities of the fibers are protonated to give a positive charge: NH3+, so that there's an interaction with the negative dye charge, allowing the formation of ionic interactions. Also, Vander Walls bonds, dipolar bonds, and hydrogen bonds are formed between dye and fiber.

Acetic acid: Its function is to control pH in the process.

Glycerin: It acts as a dispersing agent. It increases the brightness of the dye and spread the dye in the paste. Assist the dye fixation and prevent aggregation of the dye.

Thickener: Using CMC for thickener gives the required viscosity to the printing paste. It prevents premature reactions between the chemicals contained in the print paste and holds the ingredients of the print paste on the fabric.

Conclusion

In this experiment, silk fabric is printed with acid dye. The shade of printed fabric is good as required. Acid dyes are suitable for printing silk fabric.

Silk Printing