Experiment Name: Printing of 100% cotton woven fabric with vat dye by block method.
Theory: The Printing of textile materials is the application of colour according to a predetermined design. The printing paste which applied to textile material consists of dye, water, thickener and hydrocarbon solvent or oil. After the printing paste is applied, the textile material is usually steamed. Once the acid dye printing paste has been applied to the textile material, steaming of printed pattern is necessary. The steam provides the water molecules and heat energy to enable the dye molecules of the printing paste to transfer from the fibre surface into the polymer system.
Nature of Sample : Pre-treated woven fabric contains 100% cotton fibre.
Apparatus Required :
1. Beakers.
2. Glass Rod.
3. Pipette.
4. Measuring Cylinder.
5. Balance.
6. Tri-pod Stand.
7. Printing Block.
8. Pot.
9. Gas Burner.
Method Of Printing:
We used here block printing method. Block printing is the oldest method of printing which still exists but use is limited to the decoration of scarves and handkerchiefs .
There are two types of block printing exists.
I) Block printing by hand.
II) Block Printing by machine.
Style of Printing: We used here direct style for printing which means the dyes are printed directly at the required places of fabric and leaving the other portion unprinted or white.
Process Sequence:
Collection of pre-treated 100% cotton fabric
.
Preparation of print paste with thickener
.
Application of print paste on pre-treated sample according to printing method
.
Drying at 100deg C for 3-5 minutes
.
steaming at 110deg C for 5 minutes
.
After Treatment
Recipe of Printing:
Vat Dye : 20 parts
Hydrose : 20 parts.
wetting agent : 10 parts
Thickener(CMC) : 750 parts.
Water : As Required.
Function Of chemicals:
Vat Dye: The Particle which produce suitable color on the surface of fabric.
Hydrose: Here it is work as reducing agent. It reduced the insoluble vat dye for further process.
Wetting Agent: Wetting agent is substances that reduce the surface tension of water to allow it to spread drops onto a surface, increasing the spreading abilities of a liquid. Lowering the surface tension lowers the energy required to spread drops onto a film.
Thickener: It maintain proper viscosity for print paste.
Sample attachment and observation:
Comments: Here we see the printed fabric which is printed using block method. Here uneven printing done due to low viscosity of print paste.
Pre-cautions:
All chemicals measure are taken properly.
Temperature maintain properly.
Burner used very carefully.
Viscosity of print paste maintain properly.
Applied even pressure during printing process.
Conclusion:..........................................
