Printing With Direct Dye

In this article, we are going to know about the printing process of cotton fabric with direct dye. The process, the recipe etc. are described as per followed in the lab.

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Theory

By the term textile printing, we mean the localized application of dyes or pigments and chemicals by any method, which can produce a particular effect of color on the fabric according to the design. In this experiment, we print cotton fabric with direct dye in the block. It is used mostly in sarees, handkerchiefs, etc. In printing, the coloring matter used can be either dyestuff or pigments. The binder is decisively responsible for the fastness of the pigment prints during use. For dyestuff, the most important auxiliaries are the thickening agents. The use of printing thickener depends on the printing technique and fabric and dyestuff.

Objectives

To print the cotton by using a block.
To know about the printing process.
To know about the printing auxiliaries.
To know about the recipe.

Recipe

Chemicals/Parameters	Required Amount
Paste Preparation
Direct dye	1 part
Glycerin	3 parts
Na2CO3	2 parts
Thickener	60 parts
Water	As required
Thickener Preparation
CMC (Car boxy Methyl Cellulose)	8 ml
Water	92 ml
Total	100 ml
Temperature	100℃
Time	10 minutes

Procedure Flow Chart

Printing

↓

Drying

↓

Steaming

↓

Soaping

↓

Washing

Working Procedure

1. First, prepared a thickener.

2. Then took 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 prepared 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.

Sample of Printed Fabric

Direct Dye Printed Fabric

Auxiliary Chemical Functions

Direct dye: Direct dyes are molecules that adhere to the fabric molecules without help from other chemicals. It is the primary chemical substance to color the fabric, and it is an anionic dye.

Soda ash (Na2CO3): It maintains a suitable pH for direct dyeing.

Glycerin: It acts as a dispersing agent. It increases the brightness of the dye and spreads the dye evenly 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

Through this experiment, we have acquired knowledge about the process of printing cotton fibers with direct dye. The shade of printed fabric is moderately good as required.