Printing of Cotton Fabric with Reactive DyesName of the experiment: Printing of cotton fabric with reactive dyes (Block & Flat bed screen printing ). 

Introduction: 

By the term textile printing we mean the localized application of dyes or pigment and chemical by any method, which can produce particular effect of color on the fabric according to the design. In this practical we print cotton fabric with cold brand reactive dyes in block and screen-printing methods in combination method. Block printing method is the oldest printing method. It is used mostly in sarees, handkerchiefs etc. in this printing method we use blocks of different designs. In screen printing a very little screen made by glass fibre is used. There are types of screen-printing, but we have done in our experiment was hand screen-printing. Handscreen-printing is mostly used for sarees to 14-16 colors in on pattern can be produced at a time. 

Style of printing: Direct style. 

Method of printing: Block and screen-printing method. 

Sample: 

One piece of square size bleached, scoured cotton fabric (small) and one piece of square size bleached, scoured cotton fabric (bigger) 

Recipe: 

Dyes = 4gm Urea = 10gm Thickener = 50gm Resist salt=1gm Soda ash=6gm Additional water = as required. 

Preparation of thickener: 

1) 16 gm of starch and 200cc water are taken in bowl. 2) Heat is applied and solution is stirred continuously until a thick viscose solution is obtained. 3) By continuous stirring and boiling a specific viscosity is obtained. 4) The heat application is stopped otherwise viscosity falls down. So temperature is maintained strictly. 

Preparation of printing paste: 

1) At first we take required amount of dyestuffs in a bath. 2) Then little amount of water is added into the bath for mixing these dyes. And start stirring for mixing the three types of dye. 3) Then required amount of urea is added into the dye bath. 4) After then required amount of thickener is added 5) Then continuous stirring is done for few minutes for mixing all the ingredients of print paste. 6) After mixing finally required amount of alkali is added to the dye bath and mix them with the help of stirring. 

Printing process: 

Block printing method: 

1) The fabric which will be printed is placed on the printing table. 2) The printing paste is put on the tray box. 3) The block is selected and it is touched with print paste. 4) Then block is pressed upon the sample fabric. 5) After pressing the block on the sample fabric the block is put off from the fabric. 6) Finally we get the printed fabric of required dyes. 

Screen-printing method: 

1) The fabric is placed on the printing table of flat screen-printing machine. The table is made of soft by laying on it. 2) Then the screen is placed on the sample fabric. 3) The printing paste is taken on the screen perforation. 4) Thus we can find the printed fabric with a smooth wooden strike the paste is spread over the screen with slight pressure. 5) So that the dye particles can penetrate through the screen perforation. 6) Thus we get printed fabric. 

After treatment: 

The printed fabric is steamed for 5-10 minutes in a cottages steamer and washed with cold water for removing unfixed dye and exhausted thickener and then dried. 

Conclusion: 

Printing of cotton fabric with reactive dyes has excellent build up property and maximum fixation. Shade is also bright. By this experiment we have acquire knowledge about process of printing cotton fibres with cold brand reactive dyes in combination shade. The shade of printed fabric is moderately good, as we required. Special thanks to our teacher and his assistants for grate cooperation.