Brasso Print on Poleyster Cotton Blended Fabrics:

Producing Brasso Printing on A Polyester Cotton Blended Fabrics by Using Disperse Dye.

 Introduction:-

A design with clearly defined borders is created by the artistic arrangement of motifs or motives in one or more colors. Textile printing is the localized application of dyes, pigments, and chemicals to fabric using any process capable of producing a specific color effect on the cloth based on the design.

The etching-out effect is also known as brasso printing. The cellulose component of a polyester/cotton or polyester/viscose blend is burned out of the printed parts in this technique of printing by printing it with a paste containing an acid-freeing agent. As acid-freeing agents, aluminum sulphate and sodium bisulphate are commonly utilized.

Principle of the process:-

Removing cellular components from a printed portion of polyester-cotton blended fabric by using concentrated sulfuric acid.

Blend ratio used:

70/30,52/48,67/33,60/40

Style of Printing:

Direct style.

Method of Printing:

Screen-printing method

Process Sequence:

Prepare a print paste. aluminum sulphate Or Sodium bisulphate

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Printing by screen printing method

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Drying at 110°C

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Fixation by thermofixation the method at 150°C for 2 min at stenter

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Washing

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Drying. Below 80°C

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(If required) Bleaching using (NaOCl) hypochlorite or H2O2

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Washing and drying

Preparation of thickener: [Thickner (6%)-Guar gum].

preparation of a 6 % Guar gum (natural) thickener

Recipe:

Guar gum thickener(1000 gm) Guar gum Powder – 60 gm

Water ————————————————– 940 ml

Total ————————————————– 1000 gm

Screen Printing Method:

1) The fabric is placed on the flat surface of the table, which is composed of soft material.

2) The screen is then placed on the cloth sample.

The printing paste is applied to the perforation on the screen.

4) With a smooth wooden strike, the paste is distributed over the screen with light pressure, allowing us to locate the printed cloth. So that the dye particles can pass through the perforation in the screen.

5) As s result, we have printed fabric.

Screen printing method

Procedure:

1) Print the polyester/cotton blended fabric with the below recipe

Acid liberating agents used are aluminum sulphate [Al2(SO4)3] or Sodium bisulphite [NaHSO4]

Use any one of the following formulation:

Formulation 1;

Sr.No    Ingredients                      Quantity

1   Aluminum sulphate                15-20 gm

2   Citric acid                                 n2-3 gm

3    Urea                                           2-3 gm

4  Con. H2SO4.                               1 ml

5  Water                                           5-10 ml

6 Sodium alginate thickener(6%)   65-70 gm.

Total 100 gm.

Formulation 2:

Sr. No  Ingredients                           Quantity

1   Sodium bisulphate.                    15-20 gm

2   Water                                            5-10 ml

3  Urea                                               2-3 gm

4 Sodium alginate thickener (6%)  70-75 gm

Total 100 gm.

The viscosity of the print paste is very very low, if proper care is not taken then it will be flowing like a water. We should add a minimum quantity of water to paste and a maximum quantity of thickener should be added.

Ideally, Sodium alginate thickener is used however, its viscosity, as well as solid content, is too low so, after preparing paste it will create problems.

1)Hence, we are using guar gum as a Thickener having a higher solid content

2) With the above printing pastes, print the polyester/cotton or polyester/viscose blended cloth.

3) Dry the printed samples between 100 and 110°C

4) Cure the dried fabric for 2-3 minutes at 150°C.

Wash the samples after curing. At the boil, neutralize with soda ash, bleach if necessary, then wash and dry.

Reaction or mechanism of Brasso printing:

During curing the aluminum sulphate or sodium bisulphate realises sulphuric acid (H2SO4) which will remove a cellulosic component from printing paste.

High temperature gives sulfuric acid

Al2(SO4)3 + 3H2O ——> 3H2SO4 + Al2O3 or

2NaHSO4 + 3H2O —–> 2H2SO4 + Na2O

Sample Processing:-

Printing with (aluminum sulphate recipe).

Formulation 1:-

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After drying pass on to stenter at 150°C

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After fixation, the cellulosic component is removed

From the printed portion so, at printed portion only polyester component is remaining

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After washing the above brown color remain on a printed portion. 

So, to remove this brown color bleaching has to be done

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Bleaching with Hypochlorite (NaOCl)

After bleaching the brown color of the fabric is removed

SO, it is difficult to understand the polyester-cotton blended portion and only the polyester portion. So, we have to dye the sample with cold brand reactive dye

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Dyeing with cold brand reactive dye

Dyeing with cold brand reactive dye by using 2% dye solution using padding method

After dyeing, we can easily distinguish between the polyester portion and the polyester-cotton blended portion. In about sample, we can see that the printed portion is not dyed with reactive dye because it’s a polyester component.

Recipe for Bleaching:-

Sodium Hypochlorite – 2 to 3 GPL

Soda ash. – 4 to 5 GPL

Sequestic agent – 1 GPL

Water – 1000 Ml

Recipe for dyeing:

Cold brand reactive dye – 2 % (2 gm in 100 ml)

Soda ash – 10 to 15 ml

Salt – 10 to 15 ml

Use padding technique for dyeing using 2 dip 2 nip process.

Conclusion:-

Conclusion:

The Brasso effect is used to produce modified printing effects. Due to the removal of cellulosic components from printed portions, we can dye polyester with different dyes as well as dyeing the p/c blend will produce combination effects or cross dyeing effects. To get some fancy effect we can use the brasso printing technique.

ref :-https://textilelearner . net & printerest