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Page 93 - Shawl Weaving Artisan - TP
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    Textile & Handloom                                                                Exercise 1.6.55
                Shawl Weaving Artisan - Wet Processing

                Dyeing of fiber, yarn and fabric with direct dyes

                Objectives : At the end of this exercise you shall be able to
                •  dyeing the wool fiber, yarn and fabrics with direct dyes
                •  dyeing the cotton fiber, yarn and fabrics with direct dyes.

                   Requirements

                   Tools/equipment’s/Instruments
                   •  Gas stove                         - 1 No.       •  Measuring cylinders               - 1 No.
                   •  Stainless steel beaker            - 1 No.       •  Glass /metal stirring rods        - 1 No.
                   •  Direct dyes( of different shades)   - as reqd.  •  Rubber Gloves.(disposable)        - 1 Set.
                   •  Acetic acid                       - as reqd.    Materials
                   •  Soda ash                          - as reqd.    •  Wool, cotton yarn hanks           - as reqd.
                   •  Common salt                       - as reqd.    •  Wool and cotton fabric            - as reqd.
                   •  Lab thermometer                   - 1 No.
                PROCEDURE

                TASK 1: Dyeing of wool yarn with direct dyes
                Preparation                                           Cooling and rinsing
                1  Take wool yarn hank and weight it to determine the   9  Gradually cool the dye bath to around 40°C to 50°C.
                   amount of dye and chemicals required.
                                                                      10 Rinse  the wool  yarn  thoroughly  with  cold  water to
                2  Then wash the wool yarn in cold water to remove      remove any excess dye.
                   any impurities.
                                                                      Neutralization
                Dyeing                                                11 Mix acetic acid with water (around 1% to 2% of the

                3  Make a paste of dye by add it with water and mix     weight of the wool).
                   the dye with hot water (around 40°C to 50°C) in the   12 Immerse the wool yarn in the neutralizing solution.
                   dyeing vessel.
                                                                      13 Let it treat for 10-15 minutes.
                4  Then  add  salt (sodium  chloride)  to the dye bath
                   (around 10% to 20% of the weight of the wool).     Rinsing and drying
                5  Then add soda ash (sodium carbonate) to the dye    14 Rinse  the wool  yarn  thoroughly  with  cold  water to
                   bath (around 2% to 5% of the weight of the wool).    remove any remaining neutralizing solution.
                6  Then immerse the wool yarn in the dye bath.        15 Gently squeeze out excess  water from  the wool
                                                                        yarn.
                7  Heat the dye bath to (around 80°C to 90°C).
                                                                      16 Then dry the wool yarn in a room temperature.
                8  Maintain the temperature and let the wool yarn dye
                   for 60-90 minutes.

                TASK 2: Dyeing of wool fabric with direct dyes
                For wool fabric dyeing, follow the steps 1 to 16 mentioned
                in TASK 1.

                TASK 3: Dyeing of cotton yarn with direct dyes

                1  Take a cotton yarn hank and weight it to determine   4  Then  add  salt (sodium  chloride)  to the dye bath
                   the amount of dye and chemicals required.            (around  05% to 10% of the weight  of the cotton
                                                                        yarn).
                2  Then wash the cotton yarn hank in a cold water to
                   remove any impurities.                             5  Then add soda ash (sodium carbonate) to the dye
                                                                        bath (around 2% to 5% of the weight of the cotton
                3  Make a paste of dye by add it with water and mix     yarn).
                   the dye with hot water (around 40°C to 50°C) in the
                   dyeing vessel.                                     6  Then immerse the cotton yarn in the dye bath.
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