Nylon (Polyamide) Printing

Printing of Nylon (Polyamide) by Direct Style

Principle

           

Polyamide (Nylon) fabric can be printed with acid, metal complex or reactive dye as per the dyeing procedure.

ð  Printing of nylon is differs from dyeing as below:-

·         Dyes of various classes (Acid/Metal Complex/Disperse/Reactive) can be used in combination with each other.

·         Barriness of the material is minimum.

·         No blocking effect occurs.

·         Colour build up is better.

·         Fastness to water, sea water, perspiration and chlorine is essential.

Ingredients

(1)   Dyes:-

·         Acid dyes, metal complex dyes and reactive dyes are the most suitable for printing of nylon

·         Most of the disperse dyes show poor wet fastness on nylon. They are not satisfactory for printing of nylon.

·         Reactive dyes are used in a limited scale.

(2)   Thickeners:-

·         Thickeners having high solid content are best suitable for this printing.

·         Crystal gum is a very good thickener, as it produces print of good colour value and washed off easily.

·         Alginate thickener produces soft print and they are easily washed off.

·         In general low viscosity alginate is best suitable for hard fabric, while high viscosity alginate is suitable for spun and knitted fabric.

·         Modified locust bean gum prints well and do not become brittle on nylon.

·         British gum produces good colour value and paste does not coagulate.

·         Emulsion thickener produces print of good sharpness and washed off easily.

(3)   Solvent:-

·         As the dyes have limited solubility in small amount of water, Solvents and solution aids are used in the printing paste.

·         Urea, thiodiethylene glycol, glycine A are the most commonly used solvents.

·         Urea also increases colour value.

(4)   Swelling agent:-

·         Because of the smooth cylindrical fibre structure, nylon has low swelling properties.

·         To increase the swelling properties, swelling agents are used.

·         Eg. Resorcinol, Phenol

(5)   Acid Liberating agent:-

·         In order to fixed colour maximum and to provide acidic pH during fixation acid liberating agents are added in the printing paste.

·         Eg. Ammonium sulphate, Ammonium tartrate

Procedure

(1)   Printing with Acid or Metal complex dye

·         The printing paste is prepared as follows:-

5 – 10  parts    Acid or Metal complex dye

      50  parts    Urea

                        30- 50 parts    Thiodiethylene glycol

                              45 parts    Water

                    200-265   parts    Boiling water

                            600  parts    Thickener

                                5 parts    Ammonium sulphate

                          0 – 1  parts    Antifoaming agent

                          1000  parts

·         After printing, fabric is dried and steamed at 103 - 105ºC for 20 – 40 minutes.

·         After steaming, fabric is rinsed with cold water and hot water, soaped with non – ionic detergent.

·         One of the difficulties of nylon printing with acid or metal complex dye is the staining of white ground during washing.

·         This can be preventing by pre-treatment with dye fixing agent before printing or rinsing.

(2)   Printing with Disperse dye

·         The printing paste is prepared as follows:-

5 – 50  parts    Disperse dye

          50-100   parts    Water

                    200-300   parts    Urea

                    400-600   parts    Thickener

                                1  parts    Wetting agent

                          1000  parts

·         After printing and drying, the fixation of print on nylon can be carried out by any one of the following three methods:-

(a)   Pressure Steaming:- The printed fabrics are steamed at a pressure of 0.5 kg/cm² for 30 minutes.

(b)   Superheated steaming:- This method gives the best colour yield and very good feel of the fabric. Fixation with superheated steam is carried out at a temperature 160 – 190ºC for 1 minute.

(c)    Dry heat fixation:- In this method, the fixation is carried out with dry air and 170 – 200ºC for 1 – 2 minute. The feel of fabric becomes harsh in this method.

(3)   Printing with Reactive dye

·         Hot brand reactive dye or Remazol reactive dye can be used for printing of nylon fabric. The printing paste is prepared as follows:-

5 – 50  parts    Reactive dye

    100  parts    Boiling Water

    500  parts    Thickener

      30  parts    Solvent

                              30  parts    Mild oxidising agent

  1000  parts

·         After printing and drying, the fabric is steamed for 20 minutes at 7 psi.

·         Steaming is followed by cold rinse, soaping and washing.